Claude Code transcript - page 1/3

[Request interrupted by user for tool use]

Implement the following plan:

Raft KV Store Emulation Plan

Context

Create a replicated KV store using Raft consensus, matching the semantics of multipaxos_kv: put fails if key exists, get returns value or error, delete fails if key missing. Client is given leader directly (no leader discovery). The create-emulation skill requires TOML-based configuration.

Architecture

Raft vs MultiPaxos mapping

MultiPaxos KV Raft KV
Acceptor (voter) Follower node (AppendEntries responder)
Leader (proposer + state machine) Leader node (log replication + state machine)
Replica (passive learner) N/A - followers apply committed entries themselves
Phase 1 (Prepare/Promise) Leader election (RequestVote)
Phase 2 (Accept/Accepted) Log replication (AppendEntries)

Key Design Decisions

  1. Single node actor type (node.gleam): All Raft nodes are the same type with roles Leader/Follower/Candidate
  2. Simplified election at startup: Node 1 starts election immediately, wins (like multipaxos_kv's Phase 1 at init)
  3. Synchronous replication: Leader calls followers with actor.call during request handling (same pattern as multipaxos_kv's Phase 2)
  4. Commit notification: After majority ack, leader sends fire-and-forget CommitNotification to followers so they apply entries
  5. TOML config: Read num_nodes and num_clients from config file

Message Flow

Client --[ClientPut/Get/Delete]--> Leader Node
  Leader appends entry to log (term, command)
  Leader --[AppendEntries(entries)]--> all Follower Nodes (synchronous calls)
  Leader waits for majority of success responses
  Leader advances commit_index, applies to local KV store
  Leader --[reply]--> Client
  Leader --[CommitNotification(commit_index)]--> all Followers (fire-and-forget)
  Followers apply committed entries to their local KV stores

File Structure

raft_kv/
  gleam.toml
  config.toml                    -- default config: num_nodes=5, num_clients=3
  src/
    raft_kv.gleam                -- main: read TOML config, start nodes, election, clients
    raft_kv/
      types.gleam                -- Command, OpResult, LogEntry (shared types)
      node.gleam                 -- Raft node actor (all roles)
      client.gleam               -- client (adapted from multipaxos_kv/client.gleam)
  test/
    raft_kv_test.gleam           -- basic test

Implementation Details

1. types.gleam - Shared types

  • Command = Put/Get/Delete/Noop (same as multipaxos_kv/types.gleam)
  • OpResult = OpOk | OpError (same as multipaxos_kv/types.gleam)
  • LogEntry(term: Int, command: Command) - new for Raft

2. node.gleam - Raft node actor (most complex file)

State: - id, current_term, voted_for: Option(Int), role: Role - log: Dict(Int, LogEntry) - 1-indexed - commit_index, last_applied - peers: List(#(Int, Subject(Message))) - set after startup via SetPeers - store: Dict(String, String) - KV state machine - Leader-only: next_index: Dict(Int, Int), match_index: Dict(Int, Int)

Messages: - SetPeers(List(#(Int, Subject(Message)))) - configuration after startup - StartElection - trigger election (sent to node 1 by main) - RequestVote(term, candidate_id, last_log_index, last_log_term, reply_with) / VoteResponse - AppendEntries(term, leader_id, prev_log_index, prev_log_term, entries, leader_commit, reply_with) / AppendEntriesResponse - CommitNotification(leader_commit: Int) - fire-and-forget commit update - ClientPut/ClientGet/ClientDelete - same signatures as multipaxos_kv/leader.gleam

Key functions: - handle_start_election: Increment term, vote for self, call RequestVote on all peers, become leader on majority - handle_request_vote: Standard Raft voting logic (term check, log up-to-date check) - handle_append_entries: Check term, check prev_log match, append entries, update commit_index, apply - handle_client_request: (Leader only) Append to log, synchronous AppendEntries to peers, on majority: commit, apply, reply, broadcast CommitNotification - apply_committed: Apply entries from last_applied+1 to commit_index (same KV semantics as multipaxos_kv)

3. client.gleam - Adapted from multipaxos_kv/client.gleam

  • Same structure: 5 random requests, keys ["a","b","c","d","e"]
  • Calls node.put, node.get, node.delete instead of leader.*
  • References Subject(node.Message) instead of Subject(leader.Message)

4. raft_kv.gleam - Main entry point

  • Read config.toml for num_nodes (default 5) and num_clients (default 3)
  • Start N nodes, send SetPeers to each with all other nodes
  • Send StartElection to node 1, small sleep to let election complete
  • Start clients targeting node 1
  • Send Start to all clients, sleep 3s

5. config.toml

num_nodes = 5
num_clients = 3

Dependencies

gleam_stdlib, gleam_otp, gleam_erlang, tom, argv

Note: tom for TOML parsing. argv to optionally accept config file path as CLI arg.

Reusable patterns from multipaxos_kv

  • apply_command logic from multipaxos_kv/leader.gleam:106-156 (KV semantics)
  • apply_committed pattern from multipaxos_kv/replica.gleam:27-83 (sequential log application)
  • Client structure from multipaxos_kv/client.gleam (nearly identical)
  • Main wiring from multipaxos_kv/multipaxos_kv.gleam (start actors, connect, run)

Verification

  1. gleam build - compiles without errors
  2. gleam run - shows: nodes starting, election completing, clients issuing requests with Raft replication trace, followers applying committed entries
  3. gleam format - code is formatted
  4. KV semantics match: put rejects existing keys, delete rejects missing keys, get returns value or error

If you need specific details from before exiting plan mode (like exact code snippets, error messages, or content you generated), read the full transcript at: /Users/apanda/.claude/projects/-Users-apanda-code-agent-spec-code/b2f3cfa8-4232-4552-95f3-5eccc20c4847.jsonl

Thinking
ToolSearch
{
  "query": "select:Read,Glob,Write,Edit,Bash,Agent",
  "max_results": 6
}
{
  "type": "tool_reference",
  "tool_name": "Read"
}
{
  "type": "tool_reference",
  "tool_name": "Glob"
}
{
  "type": "tool_reference",
  "tool_name": "Write"
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{
  "type": "tool_reference",
  "tool_name": "Edit"
}
{
  "type": "tool_reference",
  "tool_name": "Bash"
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{
  "type": "tool_reference",
  "tool_name": "Agent"
}
Thinking

I'll start by reading the existing multipaxos_kv implementation and the create-emulation skill to understand the patterns.

Agent
Read multipaxos_kv codebase
{
  "subagent_type": "Explore",
  "prompt": "Read ALL files in the multipaxos_kv directory. I need the complete contents of every .gleam file, gleam.toml, and config.toml. Be very thorough - read every single file. The directory is at /Users/apanda/code/agent-spec-code/multipaxos_kv/. List all files first with glob, then read each one completely."
}
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/.claude/skills/create-emulation.md"
}
     1→## Metadata
     2→name: Creating a distributed system emulation
     3→description: This is a recipe for how to build a distributed system emulation in Gleam given a human description. 
     4→
     5→
     6→## Overview
     7→In this environment we use Gleam for emulation. The goal is to produce a version that can be executed and help explain how the protocol (i.e., the algorithm implemented by the system) runs.
     8→
     9→Each type of process (or node or server, I tend to use the same word for all of them) is implemented as a Gleam actor. The Gleam OTP skill that accompanies this can help write the code. Do not try to optimize the code, but be sure to use comments to document the logic of each actor, and use print statements to record the execution of each actor.
    10→
    11→Once code for all types of processes has been written, change the main function to take a configuration file (in TOML) that specifies how many nodes of each type to start and then runs them to produce an execution schedule.
    12→
    13→Finally, use the appropriate version control system to add a commit for the emulation
    14→
    15→## Steps to Create an Emulation
    16→
    17→- Use instructions from the gleam-otop skill to create and code up the emulation.
    18→- Change the main function of the newly created emulation so that it can read a configuration file written in TOML (you can read it in gleam using the `tom` package) that specifies the number of each type of process.
    19→- Create a new commit using the appropriate version control system.
    20→
    21→## Writing a new emulation
    22→
    23→Use instructions from the gleam-otp skill.
    24→
    25→## Version Control
    26→
    27→Check if the root directory contains a `.jj` directory. If so, the project is managed using Jujutsu, and the accompanying jujutsu skill to manage things.
    28→
    29→If on the other hand the root directory contains a `.git` directory (but no `.jj` directory) use git.
    30→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/.claude/skills/gleam-otp.md"
}
     1→# Gleam OTP Development
     2→
     3→## Metadata
     4→name: Gleam OTP Development
     5→description: This is a skill to help with developing Gleam OTP applications.
     6→
     7→## Creating a Gleam project
     8→
     9→```sh
    10→	gleam new --skip-git --skip-github <project name> # Create a project. Project name can only contain alphanumeric characters and `_`
    11→  cd <project name> # Change directory into the project
    12→  gleam add gleam_otp # Add gleam_otp as a dependency
    13→  gleam add gleam_erlang # Add gleam_erlang as a dependency.
    14→```
    15→
    16→## Build Commands
    17→
    18→```sh
    19→gleam build       # Compile the project
    20→gleam run         # Run the project
    21→gleam test        # Run all tests
    22→gleam add <pkg>   # Add a dependency
    23→gleam format      # Format code
    24→```
    25→
    26→## Actor Pattern with gleam_otp
    27→
    28→### Basic Actor Structure
    29→
    30→```gleam
    31→import gleam/otp/actor
    32→import gleam/erlang/process.{type Subject}
    33→
    34→// 1. Define state type
    35→pub type State {
    36→  State(value: Int, self: Subject(Message))
    37→}
    38→
    39→// 2. Define message type
    40→pub type Message {
    41→  Set(value: Int)                      // Fire-and-forget
    42→  Get(reply_with: Subject(Int))        // Request-response
    43→}
    44→
    45→// 3. Implement handler
    46→fn handle_message(state: State, message: Message) -> actor.Next(State, Message) {
    47→  case message {
    48→    Set(value) -> actor.continue(State(..state, value: value))
    49→    Get(client) -> {
    50→      process.send(client, state.value)
    51→      actor.continue(state)
    52→    }
    53→  }
    54→}
    55→
    56→// 4. Start function
    57→pub fn start() -> Result(Subject(Message), actor.StartError) {
    58→  actor.new_with_initialiser(1000, fn(self) {
    59→    actor.initialised(State(value: 0, self: self))
    60→    |> actor.returning(self)
    61→    |> Ok
    62→  })
    63→  |> actor.on_message(handle_message)
    64→  |> actor.start
    65→  |> result.map(fn(started) { started.data })
    66→}
    67→```
    68→
    69→### Key Patterns
    70→
    71→**Fire-and-forget message:**
    72→```gleam
    73→pub fn set(subject: Subject(Message), value: Int) -> Nil {
    74→  actor.send(subject, Set(value))
    75→}
    76→```
    77→
    78→**Request-response (blocking call):**
    79→```gleam
    80→pub fn get(subject: Subject(Message)) -> Int {
    81→  actor.call(subject, 1000, Get)  // 1000ms timeout
    82→}
    83→```
    84→
    85→**Self-messaging (for periodic tasks):**
    86→```gleam
    87→// In initialiser or handler:
    88→process.send_after(state.self, 100, Sync)  // Send Sync message after 100ms
    89→```
    90→
    91→**Capturing self reference:**
    92→Use `actor.new_with_initialiser` instead of `actor.new` to get access to the actor's own Subject in the initialiser callback.
    93→
    94→### Handler Return Values
    95→
    96→- `actor.continue(new_state)` - Keep running with new state
    97→- `actor.stop()` - Stop the actor gracefully
    98→
    99→### Common Imports
   100→
   101→```gleam
   102→import gleam/otp/actor
   103→import gleam/erlang/process.{type Subject}
   104→import gleam/result
   105→import gleam/list
   106→import gleam/int
   107→import gleam/io
   108→```
   109→
   110→## Testing
   111→
   112→Test functions must end with `_test` suffix:
   113→
   114→```gleam
   115→import gleeunit
   116→
   117→pub fn main() -> Nil {
   118→  gleeunit.main()
   119→}
   120→
   121→pub fn my_feature_test() {
   122→  assert some_condition == True
   123→}
   124→```
   125→
   126→## Common Patterns in This Codebase
   127→
   128→### Peer-to-peer Synchronization
   129→
   130→Servers maintain a list of peers and periodically broadcast their state:
   131→
   132→```gleam
   133→Sync -> {
   134→  list.each(state.peers, fn(peer) {
   135→    process.send(peer, Set(state.value))
   136→  })
   137→  process.send_after(state.self, 100, Sync)
   138→  actor.continue(state)
   139→}
   140→```
   141→
   142→### Convergence Check
   143→
   144→Poll until all actors have the same value:
   145→
   146→```gleam
   147→fn wait_for_convergence(servers: List(Subject(Message))) -> Nil {
   148→  let values = list.map(servers, get)
   149→  case values {
   150→    [first, ..rest] -> {
   151→      let all_same = list.all(rest, fn(v) { v == first })
   152→      case all_same && first > 0 {
   153→        True -> io.println("Converged!")
   154→        False -> {
   155→          process.sleep(100)
   156→          wait_for_convergence(servers)
   157→        }
   158→      }
   159→    }
   160→    [] -> Nil
   161→  }
   162→}
   163→```
   164→
   165→## Gleam Syntax Quick Reference
   166→
   167→**Pattern matching:**
   168→```gleam
   169→case value {
   170→  Some(x) -> x
   171→  None -> 0
   172→}
   173→```
   174→
   175→**Record update:**
   176→```gleam
   177→State(..state, value: new_value)
   178→```
   179→
   180→**Pipe operator:**
   181→```gleam
   182→value
   183→|> transform1
   184→|> transform2
   185→```
   186→
   187→**Assert (panics on failure):**
   188→```gleam
   189→let assert Ok(result) = maybe_fails()
   190→```
   191→
   192→**List operations:**
   193→```gleam
   194→list.map(items, fn(x) { x + 1 })
   195→list.each(items, fn(x) { io.println(x) })
   196→list.all(items, fn(x) { x > 0 })
   197→list.flat_map(items, fn(x) { [x, x] })
   198→```
   199→
Perfect! I have now read all the files in the multipaxos_kv directory. Let me provide you with a complete summary:

## Complete Contents of multipaxos_kv Directory

I have successfully read ALL files from the multipaxos_kv directory. Here's what's included:

### Configuration Files

**gleam.toml** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/gleam.toml`
- Project name: multipaxos_kv, version 1.0.0
- Dependencies:
  - gleam_stdlib >= 0.44.0 and < 2.0.0
  - gleam_otp >= 1.2.0 and < 2.0.0
  - gleam_erlang >= 1.3.0 and < 2.0.0
  - argv >= 1.0.2 and < 2.0.0
- Dev dependency: gleeunit >= 1.0.0 and < 2.0.0

**manifest.toml** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/manifest.toml`
- Auto-generated manifest tracking exact versions of all packages (argv 1.0.2, gleam_erlang 1.3.0, gleam_otp 1.2.0, gleam_stdlib 0.70.0, gleeunit 1.9.0)

**README.md** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/README.md`
- Standard project documentation with commands to add the package, example usage, and dev instructions

### Source Files

**multipaxos_kv.gleam** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv.gleam`
- Main entry point
- Parses command-line args for number of clients (default: 3)
- Starts 3 acceptors, 2 replicas, 1 leader
- Creates and starts N clients to send requests
- Waits 3 seconds then exits

**types.gleam** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/types.gleam`
- Defines core types:
  - `Ballot(round, leader_id)` - ballot numbers for Paxos
  - `Command` - Put, Get, Delete, Noop operations
  - `OpResult` - OpOk or OpError results
- Includes `compare_ballots` function for ballot comparison

**acceptor.gleam** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/acceptor.gleam`
- Acceptor actor implementation (Phase 1 & 2 of Paxos)
- Maintains `promised_ballot` and `accepted` dict
- Handles Prepare and Accept messages
- Returns PrepareResponse (Promise or PrepareRejected) and AcceptResponse (Accepted or AcceptRejected)

**leader.gleam** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/leader.gleam`
- Leader/proposer actor with local KV store
- Runs Phase 1 (prepare) during init to establish leadership
- Handles client requests: ClientPut, ClientGet, ClientDelete
- Runs Phase 2 (accept) for each client request
- Applies commands to local store and broadcasts to replicas
- Provides public functions: `put()`, `get()`, `delete()`

**replica.gleam** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/replica.gleam`
- Replica actor (passive learner)
- Maintains log and KV store
- Handles Commit messages from leader
- Applies committed commands in order to local store
- Supports Put, Get, Delete, and Noop operations

**client.gleam** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/client.gleam`
- Client actor that generates random requests
- Sends 5 random requests to leader (get, put, or delete)
- Randomly selects from keys: a, b, c, d, e
- Values generated as: val_<0-99>
- Responds to Start and Continue messages

### Test File

**multipaxos_kv_test.gleam** - `/Users/apanda/code/agent-spec-code/multipaxos_kv/test/multipaxos_kv_test.gleam`
- Single test: `leader_put_get_test()`
- Creates 3 acceptors, 2 replicas, 1 leader
- Tests: put, get with existing key, put to existing key (error), delete, get non-existent, delete non-existent (error)

Note: There is no config.toml file in this directory.
agentId: a663148104a983064 (for resuming to continue this agent's work if needed)
<usage>total_tokens: 31493
tool_uses: 15
duration_ms: 25147</usage>

Now let me read the actual source files from multipaxos_kv to get the exact code patterns.

Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv.gleam"
}
     1→import argv
     2→import gleam/erlang/process
     3→import gleam/int
     4→import gleam/io
     5→import gleam/list
     6→import multipaxos_kv/acceptor
     7→import multipaxos_kv/client
     8→import multipaxos_kv/leader
     9→import multipaxos_kv/replica
    10→
    11→/// Helper to create a list [1, 2, ..., n]
    12→fn range_list(n: Int) -> List(Int) {
    13→  int.range(1, n + 1, [], fn(acc, i) { [i, ..acc] })
    14→  |> list.reverse
    15→}
    16→
    17→pub fn main() -> Nil {
    18→  // Parse number of clients from command-line args (default: 3)
    19→  let num_clients = case argv.load().arguments {
    20→    [n_str, ..] -> {
    21→      case int.parse(n_str) {
    22→        Ok(n) if n > 0 -> n
    23→        _ -> {
    24→          io.println("Usage: gleam run -- <num_clients>")
    25→          panic as "num_clients must be a positive integer"
    26→        }
    27→      }
    28→    }
    29→    [] -> 3
    30→  }
    31→
    32→  // Start 3 acceptors
    33→  let acceptors =
    34→    range_list(3)
    35→    |> list.map(fn(i) {
    36→      let assert Ok(a) = acceptor.start(i)
    37→      io.println("Started acceptor " <> int.to_string(i))
    38→      a
    39→    })
    40→
    41→  // Start 2 replicas
    42→  let replicas =
    43→    range_list(2)
    44→    |> list.map(fn(i) {
    45→      let assert Ok(r) = replica.start(i)
    46→      io.println("Started replica " <> int.to_string(i))
    47→      r
    48→    })
    49→
    50→  // Start the leader (runs Phase 1 during init)
    51→  let assert Ok(the_leader) = leader.start(1, acceptors, replicas)
    52→  io.println("Started leader")
    53→
    54→  // Start clients
    55→  let clients =
    56→    range_list(num_clients)
    57→    |> list.map(fn(i) {
    58→      let assert Ok(c) = client.start(the_leader)
    59→      io.println("Started client " <> int.to_string(i))
    60→      c
    61→    })
    62→
    63→  // Tell each client to begin sending requests
    64→  list.each(clients, fn(c) { process.send(c, client.Start) })
    65→  io.println(
    66→    "All " <> int.to_string(num_clients) <> " clients started sending requests",
    67→  )
    68→
    69→  // Wait for clients to finish
    70→  process.sleep(3000)
    71→  io.println("Done")
    72→}
    73→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/types.gleam"
}
     1→import gleam/int
     2→import gleam/order.{type Order}
     3→
     4→/// A Paxos ballot number, consisting of a round and leader ID.
     5→/// Higher round wins; ties broken by leader_id.
     6→pub type Ballot {
     7→  Ballot(round: Int, leader_id: Int)
     8→}
     9→
    10→/// Compare two ballots. Higher round wins; ties broken by leader_id.
    11→pub fn compare_ballots(a: Ballot, b: Ballot) -> Order {
    12→  case a.round == b.round {
    13→    True -> int.compare(a.leader_id, b.leader_id)
    14→    False -> int.compare(a.round, b.round)
    15→  }
    16→}
    17→
    18→/// A command to be replicated through Paxos.
    19→pub type Command {
    20→  Put(key: String, value: String)
    21→  Get(key: String)
    22→  Delete(key: String)
    23→  Noop
    24→}
    25→
    26→/// Result of applying a command to the KV store.
    27→pub type OpResult {
    28→  OpOk
    29→  OpError(reason: String)
    30→}
    31→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/leader.gleam"
}
     1→import gleam/dict.{type Dict}
     2→import gleam/erlang/process.{type Subject}
     3→import gleam/int
     4→import gleam/io
     5→import gleam/list
     6→import gleam/otp/actor
     7→import gleam/result
     8→import multipaxos_kv/acceptor
     9→import multipaxos_kv/replica
    10→import multipaxos_kv/types.{type Ballot, type Command}
    11→
    12→/// Leader state: proposer + learner + KV state machine
    13→pub type State {
    14→  State(
    15→    id: Int,
    16→    ballot: Ballot,
    17→    acceptors: List(Subject(acceptor.Message)),
    18→    replicas: List(Subject(replica.Message)),
    19→    quorum_size: Int,
    20→    next_slot: Int,
    21→    log: Dict(Int, Command),
    22→    store: Dict(String, String),
    23→    last_applied: Int,
    24→    self: Subject(Message),
    25→  )
    26→}
    27→
    28→/// Messages the leader handles
    29→pub type Message {
    30→  /// Client request to insert a key-value pair
    31→  ClientPut(key: String, value: String, reply_with: Subject(types.OpResult))
    32→  /// Client request to get a value by key
    33→  ClientGet(key: String, reply_with: Subject(Result(String, String)))
    34→  /// Client request to delete a key
    35→  ClientDelete(key: String, reply_with: Subject(types.OpResult))
    36→}
    37→
    38→/// Run Phase 1 (prepare) against all acceptors. Panics if quorum not reached.
    39→fn run_phase1(
    40→  ballot: Ballot,
    41→  acceptors: List(Subject(acceptor.Message)),
    42→  quorum_size: Int,
    43→) -> Nil {
    44→  io.println(
    45→    "[leader] Phase 1: sending Prepare("
    46→    <> int.to_string(ballot.round)
    47→    <> ","
    48→    <> int.to_string(ballot.leader_id)
    49→    <> ") to "
    50→    <> int.to_string(list.length(acceptors))
    51→    <> " acceptors",
    52→  )
    53→  let promises =
    54→    list.filter_map(acceptors, fn(acc) {
    55→      let response = actor.call(acc, 1000, acceptor.Prepare(ballot, _))
    56→      case response {
    57→        acceptor.Promise(_accepted) -> Ok(Nil)
    58→        acceptor.PrepareRejected(_) -> Error(Nil)
    59→      }
    60→    })
    61→  let num_promises = list.length(promises)
    62→  io.println(
    63→    "[leader] Phase 1 complete: "
    64→    <> int.to_string(num_promises)
    65→    <> " promises received (need "
    66→    <> int.to_string(quorum_size)
    67→    <> ")",
    68→  )
    69→  case num_promises >= quorum_size {
    70→    True -> Nil
    71→    False -> panic as "Failed to get quorum in Phase 1"
    72→  }
    73→}
    74→
    75→/// Run Phase 2 (accept) for a single slot. Returns True if quorum accepted.
    76→fn run_phase2(
    77→  slot: Int,
    78→  ballot: Ballot,
    79→  command: Command,
    80→  acceptors: List(Subject(acceptor.Message)),
    81→  quorum_size: Int,
    82→) -> Bool {
    83→  let accepted_count =
    84→    list.filter_map(acceptors, fn(acc) {
    85→      let response =
    86→        actor.call(acc, 1000, acceptor.Accept(slot, ballot, command, _))
    87→      case response {
    88→        acceptor.Accepted(_) -> Ok(Nil)
    89→        acceptor.AcceptRejected(_, _) -> Error(Nil)
    90→      }
    91→    })
    92→    |> list.length
    93→  io.println(
    94→    "[leader] Phase 2 for slot "
    95→    <> int.to_string(slot)
    96→    <> ": "
    97→    <> int.to_string(accepted_count)
    98→    <> "/"
    99→    <> int.to_string(quorum_size)
   100→    <> " accepted",
   101→  )
   102→  accepted_count >= quorum_size
   103→}
   104→
   105→/// Apply a command to the KV store, returning the result and updated store
   106→fn apply_command(
   107→  command: Command,
   108→  store: Dict(String, String),
   109→) -> #(Dict(String, String), Command, types.OpResult, Result(String, String)) {
   110→  case command {
   111→    types.Put(key, value) -> {
   112→      case dict.has_key(store, key) {
   113→        True -> {
   114→          io.println("[leader] PUT \"" <> key <> "\" -> REJECTED (key exists)")
   115→          #(
   116→            store,
   117→            command,
   118→            types.OpError("key already exists: " <> key),
   119→            Error(""),
   120→          )
   121→        }
   122→        False -> {
   123→          io.println(
   124→            "[leader] PUT \"" <> key <> "\" = \"" <> value <> "\" -> OK",
   125→          )
   126→          #(dict.insert(store, key, value), command, types.OpOk, Error(""))
   127→        }
   128→      }
   129→    }
   130→    types.Get(key) -> {
   131→      case dict.get(store, key) {
   132→        Ok(value) -> {
   133→          io.println("[leader] GET \"" <> key <> "\" -> \"" <> value <> "\"")
   134→          #(store, command, types.OpOk, Ok(value))
   135→        }
   136→        Error(_) -> {
   137→          io.println("[leader] GET \"" <> key <> "\" -> NOT FOUND")
   138→          #(store, command, types.OpOk, Error("key not found: " <> key))
   139→        }
   140→      }
   141→    }
   142→    types.Delete(key) -> {
   143→      case dict.has_key(store, key) {
   144→        True -> {
   145→          io.println("[leader] DELETE \"" <> key <> "\" -> OK")
   146→          #(dict.delete(store, key), command, types.OpOk, Error(""))
   147→        }
   148→        False -> {
   149→          io.println("[leader] DELETE \"" <> key <> "\" -> NOT FOUND")
   150→          #(store, command, types.OpError("key not found: " <> key), Error(""))
   151→        }
   152→      }
   153→    }
   154→    types.Noop -> #(store, command, types.OpOk, Error(""))
   155→  }
   156→}
   157→
   158→/// Broadcast a committed command to all replicas
   159→fn broadcast_commit(
   160→  replicas: List(Subject(replica.Message)),
   161→  slot: Int,
   162→  command: Command,
   163→) -> Nil {
   164→  list.each(replicas, fn(r) { process.send(r, replica.Commit(slot, command)) })
   165→}
   166→
   167→/// Handle a client request: assign slot, run Phase 2, apply, reply, broadcast
   168→fn handle_client_request(
   169→  state: State,
   170→  command: Command,
   171→  reply_put: fn(types.OpResult) -> Nil,
   172→  reply_get: fn(Result(String, String)) -> Nil,
   173→) -> actor.Next(State, Message) {
   174→  let slot = state.next_slot
   175→  io.println(
   176→    "[leader] Assigning slot " <> int.to_string(slot) <> " for client request",
   177→  )
   178→
   179→  // Run Phase 2 for this slot
   180→  let committed =
   181→    run_phase2(slot, state.ballot, command, state.acceptors, state.quorum_size)
   182→
   183→  case committed {
   184→    True -> {
   185→      // Apply to local KV store
   186→      let #(new_store, cmd, op_result, get_result) =
   187→        apply_command(command, state.store)
   188→      let new_log = dict.insert(state.log, slot, cmd)
   189→
   190→      // Reply to client
   191→      reply_put(op_result)
   192→      reply_get(get_result)
   193→
   194→      // Broadcast commit to replicas
   195→      broadcast_commit(state.replicas, slot, cmd)
   196→
   197→      actor.continue(
   198→        State(
   199→          ..state,
   200→          next_slot: slot + 1,
   201→          log: new_log,
   202→          store: new_store,
   203→          last_applied: slot,
   204→        ),
   205→      )
   206→    }
   207→    False -> {
   208→      io.println("[leader] Phase 2 FAILED for slot " <> int.to_string(slot))
   209→      reply_put(types.OpError("consensus failed"))
   210→      reply_get(Error("consensus failed"))
   211→      actor.continue(state)
   212→    }
   213→  }
   214→}
   215→
   216→/// Handle incoming messages
   217→fn handle_message(state: State, message: Message) -> actor.Next(State, Message) {
   218→  case message {
   219→    ClientPut(key, value, reply_with) -> {
   220→      handle_client_request(
   221→        state,
   222→        types.Put(key, value),
   223→        fn(r) { process.send(reply_with, r) },
   224→        fn(_) { Nil },
   225→      )
   226→    }
   227→    ClientGet(key, reply_with) -> {
   228→      handle_client_request(state, types.Get(key), fn(_) { Nil }, fn(r) {
   229→        process.send(reply_with, r)
   230→      })
   231→    }
   232→    ClientDelete(key, reply_with) -> {
   233→      handle_client_request(
   234→        state,
   235→        types.Delete(key),
   236→        fn(r) { process.send(reply_with, r) },
   237→        fn(_) { Nil },
   238→      )
   239→    }
   240→  }
   241→}
   242→
   243→/// Start a leader actor. Runs Phase 1 during initialization.
   244→pub fn start(
   245→  id: Int,
   246→  acceptors: List(Subject(acceptor.Message)),
   247→  replicas: List(Subject(replica.Message)),
   248→) -> Result(Subject(Message), actor.StartError) {
   249→  let ballot = types.Ballot(round: 1, leader_id: id)
   250→  let quorum_size = list.length(acceptors) / 2 + 1
   251→
   252→  actor.new_with_initialiser(5000, fn(self) {
   253→    io.println("[leader] Starting with id " <> int.to_string(id))
   254→
   255→    // Run Phase 1 to establish leadership
   256→    run_phase1(ballot, acceptors, quorum_size)
   257→    io.println("[leader] Phase 1 complete — leader established")
   258→
   259→    let state =
   260→      State(
   261→        id: id,
   262→        ballot: ballot,
   263→        acceptors: acceptors,
   264→        replicas: replicas,
   265→        quorum_size: quorum_size,
   266→        next_slot: 1,
   267→        log: dict.new(),
   268→        store: dict.new(),
   269→        last_applied: 0,
   270→        self: self,
   271→      )
   272→    actor.initialised(state)
   273→    |> actor.returning(self)
   274→    |> Ok
   275→  })
   276→  |> actor.on_message(handle_message)
   277→  |> actor.start
   278→  |> result.map(fn(started) { started.data })
   279→}
   280→
   281→/// Put a key-value pair. Returns error if the key already exists.
   282→pub fn put(
   283→  leader: Subject(Message),
   284→  key: String,
   285→  value: String,
   286→) -> types.OpResult {
   287→  actor.call(leader, 5000, ClientPut(key, value, _))
   288→}
   289→
   290→/// Get the value for a key. Returns Error if not found.
   291→pub fn get(leader: Subject(Message), key: String) -> Result(String, String) {
   292→  actor.call(leader, 5000, ClientGet(key, _))
   293→}
   294→
   295→/// Delete a key. Returns error if the key doesn't exist.
   296→pub fn delete(leader: Subject(Message), key: String) -> types.OpResult {
   297→  actor.call(leader, 5000, ClientDelete(key, _))
   298→}
   299→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/client.gleam"
}
     1→import gleam/erlang/process.{type Subject}
     2→import gleam/int
     3→import gleam/io
     4→import gleam/otp/actor
     5→import gleam/result
     6→import multipaxos_kv/leader
     7→import multipaxos_kv/types
     8→
     9→/// Client state
    10→pub type State {
    11→  State(leader: Subject(leader.Message), remaining: Int, self: Subject(Message))
    12→}
    13→
    14→/// Messages the client responds to
    15→pub type Message {
    16→  /// Kick off the client's request loop
    17→  Start
    18→  /// Internal message to continue sending the next request
    19→  Continue
    20→}
    21→
    22→/// A small pool of keys the client randomly picks from
    23→const keys = #("a", "b", "c", "d", "e")
    24→
    25→/// Pick a random key from the pool
    26→fn random_key() -> String {
    27→  case int.random(5) {
    28→    0 -> keys.0
    29→    1 -> keys.1
    30→    2 -> keys.2
    31→    3 -> keys.3
    32→    _ -> keys.4
    33→  }
    34→}
    35→
    36→/// Pick a random value
    37→fn random_value() -> String {
    38→  "val_" <> int.to_string(int.random(100))
    39→}
    40→
    41→/// Handle incoming messages
    42→fn handle_message(state: State, message: Message) -> actor.Next(State, Message) {
    43→  case message {
    44→    Start -> {
    45→      io.println("[client] Starting — will send 5 requests")
    46→      send_next_request(state)
    47→    }
    48→    Continue -> {
    49→      send_next_request(state)
    50→    }
    51→  }
    52→}
    53→
    54→/// Send the next random request to the leader via Paxos
    55→fn send_next_request(state: State) -> actor.Next(State, Message) {
    56→  case state.remaining {
    57→    0 -> {
    58→      io.println("[client] Finished all 5 requests")
    59→      actor.stop()
    60→    }
    61→    n -> {
    62→      // Randomly choose between get (0), put (1), and delete (2)
    63→      case int.random(3) {
    64→        0 -> {
    65→          let key = random_key()
    66→          case leader.get(state.leader, key) {
    67→            Ok(value) ->
    68→              io.println(
    69→                "[client] GET \"" <> key <> "\" -> \"" <> value <> "\"",
    70→              )
    71→            Error(reason) ->
    72→              io.println("[client] GET \"" <> key <> "\" -> " <> reason)
    73→          }
    74→        }
    75→        1 -> {
    76→          let key = random_key()
    77→          let value = random_value()
    78→          case leader.put(state.leader, key, value) {
    79→            types.OpOk ->
    80→              io.println(
    81→                "[client] PUT \"" <> key <> "\" = \"" <> value <> "\" -> OK",
    82→              )
    83→            types.OpError(reason) ->
    84→              io.println(
    85→                "[client] PUT \""
    86→                <> key
    87→                <> "\" = \""
    88→                <> value
    89→                <> "\" -> "
    90→                <> reason,
    91→              )
    92→          }
    93→        }
    94→        _ -> {
    95→          let key = random_key()
    96→          case leader.delete(state.leader, key) {
    97→            types.OpOk -> io.println("[client] DELETE \"" <> key <> "\" -> OK")
    98→            types.OpError(reason) ->
    99→              io.println("[client] DELETE \"" <> key <> "\" -> " <> reason)
   100→          }
   101→        }
   102→      }
   103→
   104→      // Schedule next request
   105→      process.send(state.self, Continue)
   106→      actor.continue(State(..state, remaining: n - 1))
   107→    }
   108→  }
   109→}
   110→
   111→/// Start a client actor that will send 5 random requests to the leader
   112→pub fn start(
   113→  leader_subject: Subject(leader.Message),
   114→) -> Result(Subject(Message), actor.StartError) {
   115→  actor.new_with_initialiser(1000, fn(self) {
   116→    let state = State(leader: leader_subject, remaining: 5, self: self)
   117→    actor.initialised(state)
   118→    |> actor.returning(self)
   119→    |> Ok
   120→  })
   121→  |> actor.on_message(handle_message)
   122→  |> actor.start
   123→  |> result.map(fn(started) { started.data })
   124→}
   125→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/replica.gleam"
}
     1→import gleam/dict.{type Dict}
     2→import gleam/erlang/process.{type Subject}
     3→import gleam/int
     4→import gleam/io
     5→import gleam/otp/actor
     6→import gleam/result
     7→import multipaxos_kv/types.{type Command}
     8→
     9→/// Replica state: passive learner that applies committed commands
    10→pub type State {
    11→  State(
    12→    id: Int,
    13→    log: Dict(Int, Command),
    14→    store: Dict(String, String),
    15→    last_applied: Int,
    16→    self: Subject(Message),
    17→  )
    18→}
    19→
    20→/// Messages the replica handles
    21→pub type Message {
    22→  /// A committed command from the leader
    23→  Commit(slot: Int, command: Command)
    24→}
    25→
    26→/// Apply commands from the log in order, starting from last_applied + 1
    27→fn apply_committed(state: State) -> State {
    28→  let next_slot = state.last_applied + 1
    29→  case dict.get(state.log, next_slot) {
    30→    Error(_) -> state
    31→    Ok(command) -> {
    32→      let id_str = int.to_string(state.id)
    33→      let slot_str = int.to_string(next_slot)
    34→      let new_store = case command {
    35→        types.Put(key, value) -> {
    36→          io.println(
    37→            "[replica "
    38→            <> id_str
    39→            <> "] slot "
    40→            <> slot_str
    41→            <> ": PUT \""
    42→            <> key
    43→            <> "\" = \""
    44→            <> value
    45→            <> "\"",
    46→          )
    47→          dict.insert(state.store, key, value)
    48→        }
    49→        types.Get(key) -> {
    50→          io.println(
    51→            "[replica "
    52→            <> id_str
    53→            <> "] slot "
    54→            <> slot_str
    55→            <> ": GET \""
    56→            <> key
    57→            <> "\"",
    58→          )
    59→          state.store
    60→        }
    61→        types.Delete(key) -> {
    62→          io.println(
    63→            "[replica "
    64→            <> id_str
    65→            <> "] slot "
    66→            <> slot_str
    67→            <> ": DELETE \""
    68→            <> key
    69→            <> "\"",
    70→          )
    71→          dict.delete(state.store, key)
    72→        }
    73→        types.Noop -> {
    74→          io.println("[replica " <> id_str <> "] slot " <> slot_str <> ": NOOP")
    75→          state.store
    76→        }
    77→      }
    78→      let new_state = State(..state, store: new_store, last_applied: next_slot)
    79→      // Try to apply the next slot too (in case commits arrived out of order)
    80→      apply_committed(new_state)
    81→    }
    82→  }
    83→}
    84→
    85→/// Handle incoming messages
    86→fn handle_message(state: State, message: Message) -> actor.Next(State, Message) {
    87→  case message {
    88→    Commit(slot, command) -> {
    89→      let new_log = dict.insert(state.log, slot, command)
    90→      let new_state = apply_committed(State(..state, log: new_log))
    91→      actor.continue(new_state)
    92→    }
    93→  }
    94→}
    95→
    96→/// Start a replica actor with the given ID
    97→pub fn start(id: Int) -> Result(Subject(Message), actor.StartError) {
    98→  actor.new_with_initialiser(1000, fn(self) {
    99→    io.println("[replica " <> int.to_string(id) <> "] Starting")
   100→    let state =
   101→      State(
   102→        id: id,
   103→        log: dict.new(),
   104→        store: dict.new(),
   105→        last_applied: 0,
   106→        self: self,
   107→      )
   108→    actor.initialised(state)
   109→    |> actor.returning(self)
   110→    |> Ok
   111→  })
   112→  |> actor.on_message(handle_message)
   113→  |> actor.start
   114→  |> result.map(fn(started) { started.data })
   115→}
   116→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/multipaxos_kv/src/multipaxos_kv/acceptor.gleam"
}
     1→import gleam/dict.{type Dict}
     2→import gleam/erlang/process.{type Subject}
     3→import gleam/int
     4→import gleam/io
     5→import gleam/order
     6→import gleam/otp/actor
     7→import gleam/result
     8→import multipaxos_kv/types.{type Ballot, type Command}
     9→
    10→/// Acceptor state
    11→pub type State {
    12→  State(
    13→    id: Int,
    14→    promised_ballot: Ballot,
    15→    accepted: Dict(Int, #(Ballot, Command)),
    16→    self: Subject(Message),
    17→  )
    18→}
    19→
    20→/// Response to a Prepare request
    21→pub type PrepareResponse {
    22→  /// Promise not to accept lower ballots; includes previously accepted entries
    23→  Promise(accepted: Dict(Int, #(Ballot, Command)))
    24→  /// Rejected because a higher ballot was already promised
    25→  PrepareRejected(highest: Ballot)
    26→}
    27→
    28→/// Response to an Accept request
    29→pub type AcceptResponse {
    30→  /// Successfully accepted the value for this slot
    31→  Accepted(slot: Int)
    32→  /// Rejected because a higher ballot was already promised
    33→  AcceptRejected(slot: Int, highest: Ballot)
    34→}
    35→
    36→/// Messages the acceptor handles
    37→pub type Message {
    38→  /// Phase 1: Prepare request from a proposer
    39→  Prepare(ballot: Ballot, reply_with: Subject(PrepareResponse))
    40→  /// Phase 2: Accept request from a proposer
    41→  Accept(
    42→    slot: Int,
    43→    ballot: Ballot,
    44→    command: Command,
    45→    reply_with: Subject(AcceptResponse),
    46→  )
    47→}
    48→
    49→/// Handle incoming messages
    50→fn handle_message(state: State, message: Message) -> actor.Next(State, Message) {
    51→  let id_str = int.to_string(state.id)
    52→  case message {
    53→    Prepare(ballot, reply_with) -> {
    54→      // Accept if ballot >= promised_ballot
    55→      case types.compare_ballots(ballot, state.promised_ballot) {
    56→        order.Lt -> {
    57→          io.println(
    58→            "[acceptor "
    59→            <> id_str
    60→            <> "] PREPARE rejected (higher ballot promised)",
    61→          )
    62→          process.send(reply_with, PrepareRejected(state.promised_ballot))
    63→          actor.continue(state)
    64→        }
    65→        _ -> {
    66→          io.println(
    67→            "[acceptor "
    68→            <> id_str
    69→            <> "] PREPARE accepted, promising ballot ("
    70→            <> int.to_string(ballot.round)
    71→            <> ","
    72→            <> int.to_string(ballot.leader_id)
    73→            <> ")",
    74→          )
    75→          process.send(reply_with, Promise(state.accepted))
    76→          actor.continue(State(..state, promised_ballot: ballot))
    77→        }
    78→      }
    79→    }
    80→
    81→    Accept(slot, ballot, command, reply_with) -> {
    82→      // Accept if ballot >= promised_ballot
    83→      case types.compare_ballots(ballot, state.promised_ballot) {
    84→        order.Lt -> {
    85→          io.println(
    86→            "[acceptor "
    87→            <> id_str
    88→            <> "] ACCEPT rejected for slot "
    89→            <> int.to_string(slot),
    90→          )
    91→          process.send(reply_with, AcceptRejected(slot, state.promised_ballot))
    92→          actor.continue(state)
    93→        }
    94→        _ -> {
    95→          io.println(
    96→            "[acceptor "
    97→            <> id_str
    98→            <> "] ACCEPT for slot "
    99→            <> int.to_string(slot)
   100→            <> " -> accepted",
   101→          )
   102→          let new_accepted =
   103→            dict.insert(state.accepted, slot, #(ballot, command))
   104→          process.send(reply_with, Accepted(slot))
   105→          actor.continue(
   106→            State(..state, promised_ballot: ballot, accepted: new_accepted),
   107→          )
   108→        }
   109→      }
   110→    }
   111→  }
   112→}
   113→
   114→/// Start an acceptor actor with the given ID
   115→pub fn start(id: Int) -> Result(Subject(Message), actor.StartError) {
   116→  actor.new_with_initialiser(1000, fn(self) {
   117→    io.println("[acceptor " <> int.to_string(id) <> "] Starting")
   118→    let state =
   119→      State(
   120→        id: id,
   121→        promised_ballot: types.Ballot(round: 0, leader_id: 0),
   122→        accepted: dict.new(),
   123→        self: self,
   124→      )
   125→    actor.initialised(state)
   126→    |> actor.returning(self)
   127→    |> Ok
   128→  })
   129→  |> actor.on_message(handle_message)
   130→  |> actor.start
   131→  |> result.map(fn(started) { started.data })
   132→}
   133→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/multipaxos_kv/test/multipaxos_kv_test.gleam"
}
     1→import gleeunit
     2→import multipaxos_kv/acceptor
     3→import multipaxos_kv/leader
     4→import multipaxos_kv/replica
     5→import multipaxos_kv/types
     6→
     7→pub fn main() -> Nil {
     8→  gleeunit.main()
     9→}
    10→
    11→pub fn leader_put_get_test() {
    12→  let assert Ok(a1) = acceptor.start(1)
    13→  let assert Ok(a2) = acceptor.start(2)
    14→  let assert Ok(a3) = acceptor.start(3)
    15→  let assert Ok(r1) = replica.start(1)
    16→  let assert Ok(l) = leader.start(1, [a1, a2, a3], [r1])
    17→
    18→  let assert types.OpOk = leader.put(l, "x", "hello")
    19→  let assert Ok("hello") = leader.get(l, "x")
    20→  let assert types.OpError(_) = leader.put(l, "x", "world")
    21→  let assert types.OpOk = leader.delete(l, "x")
    22→  let assert Error(_) = leader.get(l, "x")
    23→  let assert types.OpError(_) = leader.delete(l, "x")
    24→}
    25→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/multipaxos_kv/gleam.toml"
}
     1→name = "multipaxos_kv"
     2→version = "1.0.0"
     3→
     4→# Fill out these fields if you intend to generate HTML documentation or publish
     5→# your project to the Hex package manager.
     6→#
     7→# description = ""
     8→# licences = ["Apache-2.0"]
     9→# repository = { type = "github", user = "", repo = "" }
    10→# links = [{ title = "Website", href = "" }]
    11→#
    12→# For a full reference of all the available options, you can have a look at
    13→# https://gleam.run/writing-gleam/gleam-toml/.
    14→
    15→[dependencies]
    16→gleam_stdlib = ">= 0.44.0 and < 2.0.0"
    17→gleam_otp = ">= 1.2.0 and < 2.0.0"
    18→gleam_erlang = ">= 1.3.0 and < 2.0.0"
    19→argv = ">= 1.0.2 and < 2.0.0"
    20→
    21→[dev-dependencies]
    22→gleeunit = ">= 1.0.0 and < 2.0.0"
    23→

Now I have a thorough understanding of the patterns. Let me check if any other emulation uses TOML config to see the pattern.

ToolSearch
{
  "query": "select:Grep",
  "max_results": 1
}
{
  "type": "tool_reference",
  "tool_name": "Grep"
}
Grep
{
  "pattern": "tom\\.parse",
  "output_mode": "files_with_matches"
}
No files found

No existing TOML config pattern. Let me now create the raft_kv project. First, create the project scaffolding.

$ Bash
Create raft_kv Gleam project with dependencies
gleam new --skip-git --skip-github raft_kv && cd raft_kv && gleam add gleam_otp && gleam add gleam_erlang && gleam add tom && gleam add argv
Your Gleam project raft_kv has been successfully created.
The project can be compiled and tested by running these commands:

	cd raft_kv
	gleam test

  Resolving versions
Downloading packages
 Downloaded 4 packages in 0.04s
      Added gleam_erlang v1.3.0
      Added gleam_otp v1.2.0
      Added gleam_stdlib v0.70.0
      Added gleeunit v1.9.0
  Resolving versions
  Resolving versions
Downloading packages
 Downloaded 2 packages in 0.03s
      Added gleam_time v1.7.0
      Added tom v2.0.1
  Resolving versions
Downloading packages
 Downloaded 1 package in 0.01s
      Added argv v1.0.2

Good. Now let me create all the files. I'll create them in parallel.

📝 Write config.toml
/Users/apanda/code/agent-spec-code/raft_kv/config.toml
num_nodes = 5
num_clients = 3
File created successfully at: /Users/apanda/code/agent-spec-code/raft_kv/config.toml
📝 Write types.gleam
/Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv/types.gleam
/// A command to be replicated through Raft.
pub type Command {
  Put(key: String, value: String)
  Get(key: String)
  Delete(key: String)
  Noop
}

/// Result of applying a command to the KV store.
pub type OpResult {
  OpOk
  OpError(reason: String)
}

/// A single entry in the Raft log, tagged with the term it was created in.
pub type LogEntry {
  LogEntry(term: Int, command: Command)
}
File created successfully at: /Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv/types.gleam
📝 Write node.gleam
/Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv/node.gleam
import gleam/dict.{type Dict}
import gleam/erlang/process.{type Subject}
import gleam/int
import gleam/io
import gleam/list
import gleam/option.{type Option, None, Some}
import gleam/otp/actor
import gleam/result
import raft_kv/types.{type Command, type LogEntry}

/// Role a Raft node can be in
pub type Role {
  Follower
  Candidate
  Leader
}

/// Raft node state
pub type State {
  State(
    id: Int,
    current_term: Int,
    voted_for: Option(Int),
    role: Role,
    // Log is 1-indexed: index -> LogEntry
    log: Dict(Int, LogEntry),
    commit_index: Int,
    last_applied: Int,
    // Peer nodes (id, subject) — does not include self
    peers: List(#(Int, Subject(Message))),
    // KV state machine
    store: Dict(String, String),
    // Leader-only state
    next_index: Dict(Int, Int),
    match_index: Dict(Int, Int),
    // Total number of nodes in the cluster (including self)
    cluster_size: Int,
    self: Subject(Message),
  )
}

/// Response to a RequestVote RPC
pub type VoteResponse {
  VoteGranted(term: Int)
  VoteDenied(term: Int)
}

/// Response to an AppendEntries RPC
pub type AppendEntriesResponse {
  AppendEntriesOk(term: Int, match_index: Int)
  AppendEntriesRejected(term: Int)
}

/// Messages the Raft node handles
pub type Message {
  /// Configuration: set peer nodes after all are started
  SetPeers(peers: List(#(Int, Subject(Message))))
  /// Trigger an election (sent to a designated node by main)
  StartElection
  /// RequestVote RPC from a candidate
  RequestVote(
    term: Int,
    candidate_id: Int,
    last_log_index: Int,
    last_log_term: Int,
    reply_with: Subject(VoteResponse),
  )
  /// AppendEntries RPC from the leader
  AppendEntries(
    term: Int,
    leader_id: Int,
    prev_log_index: Int,
    prev_log_term: Int,
    entries: List(#(Int, LogEntry)),
    leader_commit: Int,
    reply_with: Subject(AppendEntriesResponse),
  )
  /// Fire-and-forget notification that the leader's commit index advanced
  CommitNotification(leader_commit: Int)
  /// Client request to insert a key-value pair
  ClientPut(key: String, value: String, reply_with: Subject(types.OpResult))
  /// Client request to get a value by key
  ClientGet(key: String, reply_with: Subject(Result(String, String)))
  /// Client request to delete a key
  ClientDelete(key: String, reply_with: Subject(types.OpResult))
}

/// Get the last log index (0 if log is empty)
fn last_log_index(log: Dict(Int, LogEntry)) -> Int {
  dict.keys(log)
  |> list.fold(0, int.max)
}

/// Get the term of a log entry at a given index (0 if not present)
fn log_term_at(log: Dict(Int, LogEntry), index: Int) -> Int {
  case dict.get(log, index) {
    Ok(entry) -> entry.term
    Error(_) -> 0
  }
}

/// Compute quorum size for a cluster
fn quorum_size(cluster_size: Int) -> Int {
  cluster_size / 2 + 1
}

/// Handle the StartElection message: run a Raft leader election
fn handle_start_election(state: State) -> actor.Next(State, Message) {
  let new_term = state.current_term + 1
  let id_str = int.to_string(state.id)
  io.println(
    "[node "
    <> id_str
    <> "] Starting election for term "
    <> int.to_string(new_term),
  )

  let my_last_index = last_log_index(state.log)
  let my_last_term = log_term_at(state.log, my_last_index)

  // Vote for self
  let votes_needed = quorum_size(state.cluster_size)
  // Count self vote = 1, then call peers for votes
  let peer_votes =
    list.filter_map(state.peers, fn(peer) {
      let #(peer_id, peer_subject) = peer
      let response =
        actor.call(peer_subject, 1000, RequestVote(
          new_term,
          state.id,
          my_last_index,
          my_last_term,
          _,
        ))
      case response {
        VoteGranted(_) -> {
          io.println(
            "[node "
            <> id_str
            <> "] Received vote from node "
            <> int.to_string(peer_id),
          )
          Ok(Nil)
        }
        VoteDenied(_) -> Error(Nil)
      }
    })

  let total_votes = 1 + list.length(peer_votes)
  io.println(
    "[node "
    <> id_str
    <> "] Election result: "
    <> int.to_string(total_votes)
    <> " votes (need "
    <> int.to_string(votes_needed)
    <> ")",
  )

  case total_votes >= votes_needed {
    True -> {
      io.println("[node " <> id_str <> "] Became LEADER for term " <> int.to_string(new_term))
      // Initialize next_index and match_index for each peer
      let next_idx = last_log_index(state.log) + 1
      let new_next_index =
        list.fold(state.peers, dict.new(), fn(acc, peer) {
          dict.insert(acc, peer.0, next_idx)
        })
      let new_match_index =
        list.fold(state.peers, dict.new(), fn(acc, peer) {
          dict.insert(acc, peer.0, 0)
        })
      actor.continue(State(
        ..state,
        current_term: new_term,
        voted_for: Some(state.id),
        role: Leader,
        next_index: new_next_index,
        match_index: new_match_index,
      ))
    }
    False -> {
      io.println("[node " <> id_str <> "] Election FAILED, staying follower")
      actor.continue(State(
        ..state,
        current_term: new_term,
        voted_for: Some(state.id),
        role: Follower,
      ))
    }
  }
}

/// Handle a RequestVote RPC
fn handle_request_vote(
  state: State,
  term: Int,
  candidate_id: Int,
  candidate_last_index: Int,
  candidate_last_term: Int,
  reply_with: Subject(VoteResponse),
) -> actor.Next(State, Message) {
  let id_str = int.to_string(state.id)

  // If candidate's term is less than ours, deny
  case term < state.current_term {
    True -> {
      io.println(
        "[node "
        <> id_str
        <> "] Denying vote to "
        <> int.to_string(candidate_id)
        <> " (stale term)",
      )
      process.send(reply_with, VoteDenied(state.current_term))
      actor.continue(state)
    }
    False -> {
      // Step down if term is higher
      let updated_state = case term > state.current_term {
        True ->
          State(
            ..state,
            current_term: term,
            voted_for: None,
            role: Follower,
          )
        False -> state
      }

      // Check if we can grant the vote
      let can_vote = case updated_state.voted_for {
        None -> True
        Some(id) -> id == candidate_id
      }

      // Check log up-to-date: candidate's log must be at least as up-to-date
      let my_last_index = last_log_index(updated_state.log)
      let my_last_term = log_term_at(updated_state.log, my_last_index)
      let log_ok =
        candidate_last_term > my_last_term
        || { candidate_last_term == my_last_term && candidate_last_index >= my_last_index }

      case can_vote && log_ok {
        True -> {
          io.println(
            "[node "
            <> id_str
            <> "] Granting vote to "
            <> int.to_string(candidate_id)
            <> " for term "
            <> int.to_string(term),
          )
          process.send(reply_with, VoteGranted(term))
          actor.continue(State(
            ..updated_state,
            voted_for: Some(candidate_id),
          ))
        }
        False -> {
          io.println(
            "[node "
            <> id_str
            <> "] Denying vote to "
            <> int.to_string(candidate_id),
          )
          process.send(reply_with, VoteDenied(updated_state.current_term))
          actor.continue(updated_state)
        }
      }
    }
  }
}

/// Handle an AppendEntries RPC (from leader)
fn handle_append_entries(
  state: State,
  term: Int,
  leader_id: Int,
  prev_log_index: Int,
  prev_log_term: Int,
  entries: List(#(Int, LogEntry)),
  leader_commit: Int,
  reply_with: Subject(AppendEntriesResponse),
) -> actor.Next(State, Message) {
  let id_str = int.to_string(state.id)

  // Reject if term < current_term
  case term < state.current_term {
    True -> {
      io.println(
        "[node "
        <> id_str
        <> "] Rejecting AppendEntries from node "
        <> int.to_string(leader_id)
        <> " (stale term)",
      )
      process.send(reply_with, AppendEntriesRejected(state.current_term))
      actor.continue(state)
    }
    False -> {
      // Step down / update term if needed
      let updated_state =
        State(..state, current_term: term, role: Follower, voted_for: case
          term > state.current_term
        {
          True -> None
          False -> state.voted_for
        })

      // Check prev_log consistency
      let prev_ok = case prev_log_index {
        0 -> True
        _ -> log_term_at(updated_state.log, prev_log_index) == prev_log_term
      }

      case prev_ok {
        False -> {
          io.println(
            "[node "
            <> id_str
            <> "] AppendEntries log mismatch at index "
            <> int.to_string(prev_log_index),
          )
          process.send(
            reply_with,
            AppendEntriesRejected(updated_state.current_term),
          )
          actor.continue(updated_state)
        }
        True -> {
          // Append entries to log
          let new_log =
            list.fold(entries, updated_state.log, fn(log, entry) {
              let #(index, log_entry) = entry
              dict.insert(log, index, log_entry)
            })

          // Update commit_index
          let new_commit_index = case leader_commit > updated_state.commit_index {
            True -> {
              let last_new_index = case list.last(entries) {
                Ok(#(idx, _)) -> idx
                Error(_) -> updated_state.commit_index
              }
              int.min(leader_commit, last_new_index)
            }
            False -> updated_state.commit_index
          }

          let match_idx = last_log_index(new_log)
          io.println(
            "[node "
            <> id_str
            <> "] AppendEntries OK from leader "
            <> int.to_string(leader_id)
            <> ", match_index="
            <> int.to_string(match_idx),
          )
          process.send(
            reply_with,
            AppendEntriesOk(updated_state.current_term, match_idx),
          )

          // Apply newly committed entries
          let final_state =
            apply_committed(State(
              ..updated_state,
              log: new_log,
              commit_index: new_commit_index,
            ))
          actor.continue(final_state)
        }
      }
    }
  }
}

/// Handle a CommitNotification from the leader
fn handle_commit_notification(
  state: State,
  leader_commit: Int,
) -> actor.Next(State, Message) {
  let id_str = int.to_string(state.id)
  let new_commit_index = case leader_commit > state.commit_index {
    True -> leader_commit
    False -> state.commit_index
  }
  io.println(
    "[node "
    <> id_str
    <> "] CommitNotification: commit_index updated to "
    <> int.to_string(new_commit_index),
  )
  let new_state =
    apply_committed(State(..state, commit_index: new_commit_index))
  actor.continue(new_state)
}

/// Apply committed log entries to the KV state machine
fn apply_committed(state: State) -> State {
  let next = state.last_applied + 1
  case next > state.commit_index {
    True -> state
    False -> {
      case dict.get(state.log, next) {
        Error(_) -> state
        Ok(entry) -> {
          let id_str = int.to_string(state.id)
          let slot_str = int.to_string(next)
          let new_store = case entry.command {
            types.Put(key, value) -> {
              case dict.has_key(state.store, key) {
                True -> {
                  io.println(
                    "[node "
                    <> id_str
                    <> "] slot "
                    <> slot_str
                    <> ": PUT \""
                    <> key
                    <> "\" -> REJECTED (key exists)",
                  )
                  state.store
                }
                False -> {
                  io.println(
                    "[node "
                    <> id_str
                    <> "] slot "
                    <> slot_str
                    <> ": PUT \""
                    <> key
                    <> "\" = \""
                    <> value
                    <> "\" -> OK",
                  )
                  dict.insert(state.store, key, value)
                }
              }
            }
            types.Get(key) -> {
              case dict.get(state.store, key) {
                Ok(value) ->
                  io.println(
                    "[node "
                    <> id_str
                    <> "] slot "
                    <> slot_str
                    <> ": GET \""
                    <> key
                    <> "\" -> \""
                    <> value
                    <> "\"",
                  )
                Error(_) ->
                  io.println(
                    "[node "
                    <> id_str
                    <> "] slot "
                    <> slot_str
                    <> ": GET \""
                    <> key
                    <> "\" -> NOT FOUND",
                  )
              }
              state.store
            }
            types.Delete(key) -> {
              case dict.has_key(state.store, key) {
                True -> {
                  io.println(
                    "[node "
                    <> id_str
                    <> "] slot "
                    <> slot_str
                    <> ": DELETE \""
                    <> key
                    <> "\" -> OK",
                  )
                  dict.delete(state.store, key)
                }
                False -> {
                  io.println(
                    "[node "
                    <> id_str
                    <> "] slot "
                    <> slot_str
                    <> ": DELETE \""
                    <> key
                    <> "\" -> NOT FOUND",
                  )
                  state.store
                }
              }
            }
            types.Noop -> {
              io.println(
                "[node " <> id_str <> "] slot " <> slot_str <> ": NOOP",
              )
              state.store
            }
          }
          let new_state =
            State(..state, store: new_store, last_applied: next)
          // Recursively apply next entry
          apply_committed(new_state)
        }
      }
    }
  }
}

/// Apply a command to the KV store and return the result (used by leader for client replies)
fn apply_command_result(
  command: Command,
  store: Dict(String, String),
  id_str: String,
) -> #(Dict(String, String), types.OpResult, Result(String, String)) {
  case command {
    types.Put(key, value) -> {
      case dict.has_key(store, key) {
        True -> {
          io.println(
            "[node " <> id_str <> "] PUT \"" <> key <> "\" -> REJECTED (key exists)",
          )
          #(store, types.OpError("key already exists: " <> key), Error(""))
        }
        False -> {
          io.println(
            "[node "
            <> id_str
            <> "] PUT \""
            <> key
            <> "\" = \""
            <> value
            <> "\" -> OK",
          )
          #(dict.insert(store, key, value), types.OpOk, Error(""))
        }
      }
    }
    types.Get(key) -> {
      case dict.get(store, key) {
        Ok(value) -> {
          io.println(
            "[node " <> id_str <> "] GET \"" <> key <> "\" -> \"" <> value <> "\"",
          )
          #(store, types.OpOk, Ok(value))
        }
        Error(_) -> {
          io.println(
            "[node " <> id_str <> "] GET \"" <> key <> "\" -> NOT FOUND",
          )
          #(store, types.OpOk, Error("key not found: " <> key))
        }
      }
    }
    types.Delete(key) -> {
      case dict.has_key(store, key) {
        True -> {
          io.println("[node " <> id_str <> "] DELETE \"" <> key <> "\" -> OK")
          #(dict.delete(store, key), types.OpOk, Error(""))
        }
        False -> {
          io.println(
            "[node " <> id_str <> "] DELETE \"" <> key <> "\" -> NOT FOUND",
          )
          #(store, types.OpError("key not found: " <> key), Error(""))
        }
      }
    }
    types.Noop -> #(store, types.OpOk, Error(""))
  }
}

/// Handle a client request (leader only): append to log, replicate, commit, reply
fn handle_client_request(
  state: State,
  command: Command,
  reply_put: fn(types.OpResult) -> Nil,
  reply_get: fn(Result(String, String)) -> Nil,
) -> actor.Next(State, Message) {
  let id_str = int.to_string(state.id)

  // Only the leader handles client requests
  case state.role {
    Leader -> {
      // Append entry to local log
      let new_index = last_log_index(state.log) + 1
      let entry = types.LogEntry(term: state.current_term, command: command)
      let new_log = dict.insert(state.log, new_index, entry)
      io.println(
        "[node "
        <> id_str
        <> "] Appending entry at index "
        <> int.to_string(new_index)
        <> " (term "
        <> int.to_string(state.current_term)
        <> ")",
      )

      // Send AppendEntries to all peers (synchronous calls)
      let prev_index = new_index - 1
      let prev_term = log_term_at(state.log, prev_index)
      let entries_to_send = [#(new_index, entry)]

      let ack_count =
        list.filter_map(state.peers, fn(peer) {
          let #(peer_id, peer_subject) = peer
          let response =
            actor.call(peer_subject, 2000, AppendEntries(
              state.current_term,
              state.id,
              prev_index,
              prev_term,
              entries_to_send,
              state.commit_index,
              _,
            ))
          case response {
            AppendEntriesOk(_, match_idx) -> {
              io.println(
                "[node "
                <> id_str
                <> "] AppendEntries ACK from node "
                <> int.to_string(peer_id)
                <> " (match="
                <> int.to_string(match_idx)
                <> ")",
              )
              Ok(#(peer_id, match_idx))
            }
            AppendEntriesRejected(_) -> {
              io.println(
                "[node "
                <> id_str
                <> "] AppendEntries NACK from node "
                <> int.to_string(peer_id),
              )
              Error(Nil)
            }
          }
        })

      // Count: self + successful acks
      let total_acks = 1 + list.length(ack_count)
      let needed = quorum_size(state.cluster_size)
      io.println(
        "[node "
        <> id_str
        <> "] Replication: "
        <> int.to_string(total_acks)
        <> "/"
        <> int.to_string(needed)
        <> " acks",
      )

      case total_acks >= needed {
        True -> {
          // Commit: advance commit_index and apply
          let new_commit_index = new_index
          let #(new_store, op_result, get_result) =
            apply_command_result(command, state.store, id_str)

          // Reply to client
          reply_put(op_result)
          reply_get(get_result)

          // Update match_index for peers that acked
          let new_match_index =
            list.fold(ack_count, state.match_index, fn(acc, ack) {
              let #(peer_id, match_idx) = ack
              dict.insert(acc, peer_id, match_idx)
            })

          // Send CommitNotification to all peers (fire-and-forget)
          list.each(state.peers, fn(peer) {
            process.send(peer.1, CommitNotification(new_commit_index))
          })

          actor.continue(State(
            ..state,
            log: new_log,
            commit_index: new_commit_index,
            last_applied: new_index,
            store: new_store,
            match_index: new_match_index,
          ))
        }
        False -> {
          io.println(
            "[node "
            <> id_str
            <> "] Replication FAILED for index "
            <> int.to_string(new_index),
          )
          reply_put(types.OpError("replication failed"))
          reply_get(Error("replication failed"))
          actor.continue(State(..state, log: new_log))
        }
      }
    }
    _ -> {
      io.println("[node " <> id_str <> "] Not leader, rejecting client request")
      reply_put(types.OpError("not leader"))
      reply_get(Error("not leader"))
      actor.continue(state)
    }
  }
}

/// Handle incoming messages
fn handle_message(state: State, message: Message) -> actor.Next(State, Message) {
  case message {
    SetPeers(peers) -> {
      io.println(
        "[node "
        <> int.to_string(state.id)
        <> "] Peers configured ("
        <> int.to_string(list.length(peers))
        <> " peers)",
      )
      actor.continue(State(..state, peers: peers))
    }

    StartElection -> handle_start_election(state)

    RequestVote(term, candidate_id, last_idx, last_term, reply_with) ->
      handle_request_vote(
        state,
        term,
        candidate_id,
        last_idx,
        last_term,
        reply_with,
      )

    AppendEntries(
      term,
      leader_id,
      prev_index,
      prev_term,
      entries,
      leader_commit,
      reply_with,
    ) ->
      handle_append_entries(
        state,
        term,
        leader_id,
        prev_index,
        prev_term,
        entries,
        leader_commit,
        reply_with,
      )

    CommitNotification(leader_commit) ->
      handle_commit_notification(state, leader_commit)

    ClientPut(key, value, reply_with) ->
      handle_client_request(
        state,
        types.Put(key, value),
        fn(r) { process.send(reply_with, r) },
        fn(_) { Nil },
      )

    ClientGet(key, reply_with) ->
      handle_client_request(state, types.Get(key), fn(_) { Nil }, fn(r) {
        process.send(reply_with, r)
      })

    ClientDelete(key, reply_with) ->
      handle_client_request(
        state,
        types.Delete(key),
        fn(r) { process.send(reply_with, r) },
        fn(_) { Nil },
      )
  }
}

/// Start a Raft node actor with the given ID and cluster size
pub fn start(
  id: Int,
  cluster_size: Int,
) -> Result(Subject(Message), actor.StartError) {
  actor.new_with_initialiser(1000, fn(self) {
    io.println("[node " <> int.to_string(id) <> "] Starting")
    let state =
      State(
        id: id,
        current_term: 0,
        voted_for: None,
        role: Follower,
        log: dict.new(),
        commit_index: 0,
        last_applied: 0,
        peers: [],
        store: dict.new(),
        next_index: dict.new(),
        match_index: dict.new(),
        cluster_size: cluster_size,
        self: self,
      )
    actor.initialised(state)
    |> actor.returning(self)
    |> Ok
  })
  |> actor.on_message(handle_message)
  |> actor.start
  |> result.map(fn(started) { started.data })
}

/// Put a key-value pair. Returns error if the key already exists.
pub fn put(
  node: Subject(Message),
  key: String,
  value: String,
) -> types.OpResult {
  actor.call(node, 5000, ClientPut(key, value, _))
}

/// Get the value for a key. Returns Error if not found.
pub fn get(node: Subject(Message), key: String) -> Result(String, String) {
  actor.call(node, 5000, ClientGet(key, _))
}

/// Delete a key. Returns error if the key doesn't exist.
pub fn delete(node: Subject(Message), key: String) -> types.OpResult {
  actor.call(node, 5000, ClientDelete(key, _))
}
File created successfully at: /Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv/node.gleam
📝 Write client.gleam
/Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv/client.gleam
import gleam/erlang/process.{type Subject}
import gleam/int
import gleam/io
import gleam/otp/actor
import gleam/result
import raft_kv/node
import raft_kv/types

/// Client state
pub type State {
  State(leader: Subject(node.Message), remaining: Int, self: Subject(Message))
}

/// Messages the client responds to
pub type Message {
  /// Kick off the client's request loop
  Start
  /// Internal message to continue sending the next request
  Continue
}

/// A small pool of keys the client randomly picks from
const keys = #("a", "b", "c", "d", "e")

/// Pick a random key from the pool
fn random_key() -> String {
  case int.random(5) {
    0 -> keys.0
    1 -> keys.1
    2 -> keys.2
    3 -> keys.3
    _ -> keys.4
  }
}

/// Pick a random value
fn random_value() -> String {
  "val_" <> int.to_string(int.random(100))
}

/// Handle incoming messages
fn handle_message(state: State, message: Message) -> actor.Next(State, Message) {
  case message {
    Start -> {
      io.println("[client] Starting — will send 5 requests")
      send_next_request(state)
    }
    Continue -> {
      send_next_request(state)
    }
  }
}

/// Send the next random request to the leader via Raft
fn send_next_request(state: State) -> actor.Next(State, Message) {
  case state.remaining {
    0 -> {
      io.println("[client] Finished all 5 requests")
      actor.stop()
    }
    n -> {
      // Randomly choose between get (0), put (1), and delete (2)
      case int.random(3) {
        0 -> {
          let key = random_key()
          case node.get(state.leader, key) {
            Ok(value) ->
              io.println(
                "[client] GET \"" <> key <> "\" -> \"" <> value <> "\"",
              )
            Error(reason) ->
              io.println("[client] GET \"" <> key <> "\" -> " <> reason)
          }
        }
        1 -> {
          let key = random_key()
          let value = random_value()
          case node.put(state.leader, key, value) {
            types.OpOk ->
              io.println(
                "[client] PUT \"" <> key <> "\" = \"" <> value <> "\" -> OK",
              )
            types.OpError(reason) ->
              io.println(
                "[client] PUT \""
                <> key
                <> "\" = \""
                <> value
                <> "\" -> "
                <> reason,
              )
          }
        }
        _ -> {
          let key = random_key()
          case node.delete(state.leader, key) {
            types.OpOk -> io.println("[client] DELETE \"" <> key <> "\" -> OK")
            types.OpError(reason) ->
              io.println("[client] DELETE \"" <> key <> "\" -> " <> reason)
          }
        }
      }

      // Schedule next request
      process.send(state.self, Continue)
      actor.continue(State(..state, remaining: n - 1))
    }
  }
}

/// Start a client actor that will send 5 random requests to the leader node
pub fn start(
  leader_subject: Subject(node.Message),
) -> Result(Subject(Message), actor.StartError) {
  actor.new_with_initialiser(1000, fn(self) {
    let state = State(leader: leader_subject, remaining: 5, self: self)
    actor.initialised(state)
    |> actor.returning(self)
    |> Ok
  })
  |> actor.on_message(handle_message)
  |> actor.start
  |> result.map(fn(started) { started.data })
}
File created successfully at: /Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv/client.gleam
📝 Write raft_kv.gleam
/Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv.gleam
import argv
import gleam/erlang/process
import gleam/int
import gleam/io
import gleam/list
import gleam/result
import raft_kv/client
import raft_kv/node
import tom

/// Helper to create a list [1, 2, ..., n]
fn range_list(n: Int) -> List(Int) {
  int.range(1, n + 1, [], fn(acc, i) { [i, ..acc] })
  |> list.reverse
}

/// Read the config file and return (num_nodes, num_clients)
fn read_config(path: String) -> #(Int, Int) {
  let assert Ok(content) = read_file(path)
  let assert Ok(parsed) = tom.parse(content)

  let num_nodes =
    tom.get_int(parsed, ["num_nodes"])
    |> result.unwrap(5)

  let num_clients =
    tom.get_int(parsed, ["num_clients"])
    |> result.unwrap(3)

  #(num_nodes, num_clients)
}

/// Read a file as a string (using Erlang's file module)
@external(erlang, "file", "read_file")
fn do_read_file(path: String) -> Result(BitArray, dynamic)

import gleam/bit_array

fn read_file(path: String) -> Result(String, Nil) {
  case do_read_file(path) {
    Ok(bits) -> bit_array.to_string(bits) |> result.nil_error
    Error(_) -> Error(Nil)
  }
}

pub fn main() -> Nil {
  // Determine config file path from args or default
  let config_path = case argv.load().arguments {
    [path, ..] -> path
    [] -> "config.toml"
  }

  let #(num_nodes, num_clients) = read_config(config_path)
  io.println(
    "Config: "
    <> int.to_string(num_nodes)
    <> " nodes, "
    <> int.to_string(num_clients)
    <> " clients",
  )

  // Start N Raft nodes
  let nodes =
    range_list(num_nodes)
    |> list.map(fn(i) {
      let assert Ok(n) = node.start(i, num_nodes)
      io.println("Started node " <> int.to_string(i))
      #(i, n)
    })

  // Send SetPeers to each node with all other nodes
  list.each(nodes, fn(node_pair) {
    let #(id, subject) = node_pair
    let peers = list.filter(nodes, fn(p) { p.0 != id })
    process.send(subject, node.SetPeers(peers))
  })
  io.println("All peers configured")

  // Trigger election on node 1
  let assert Ok(#(_, leader_subject)) =
    list.find(nodes, fn(n) { n.0 == 1 })
  process.send(leader_subject, node.StartElection)

  // Small sleep to let election complete
  process.sleep(200)
  io.println("Election complete, starting clients")

  // Start clients targeting node 1 (the leader)
  let clients =
    range_list(num_clients)
    |> list.map(fn(i) {
      let assert Ok(c) = client.start(leader_subject)
      io.println("Started client " <> int.to_string(i))
      c
    })

  // Tell each client to begin sending requests
  list.each(clients, fn(c) { process.send(c, client.Start) })
  io.println(
    "All " <> int.to_string(num_clients) <> " clients started sending requests",
  )

  // Wait for clients to finish
  process.sleep(3000)
  io.println("Done")
}
<tool_use_error>File has not been read yet. Read it first before writing to it.</tool_use_error>
📝 Write raft_kv_test.gleam
/Users/apanda/code/agent-spec-code/raft_kv/test/raft_kv_test.gleam
import gleam/erlang/process
import gleeunit
import raft_kv/node
import raft_kv/types

pub fn main() -> Nil {
  gleeunit.main()
}

pub fn raft_put_get_test() {
  // Start 3 nodes
  let assert Ok(n1) = node.start(1, 3)
  let assert Ok(n2) = node.start(2, 3)
  let assert Ok(n3) = node.start(3, 3)

  // Configure peers
  process.send(n1, node.SetPeers([#(2, n2), #(3, n3)]))
  process.send(n2, node.SetPeers([#(1, n1), #(3, n3)]))
  process.send(n3, node.SetPeers([#(1, n1), #(2, n2)]))

  // Elect node 1 as leader
  process.send(n1, node.StartElection)
  process.sleep(100)

  // Test KV operations
  let assert types.OpOk = node.put(n1, "x", "hello")
  let assert Ok("hello") = node.get(n1, "x")
  let assert types.OpError(_) = node.put(n1, "x", "world")
  let assert types.OpOk = node.delete(n1, "x")
  let assert Error(_) = node.get(n1, "x")
  let assert types.OpError(_) = node.delete(n1, "x")
}
<tool_use_error>File has not been read yet. Read it first before writing to it.</tool_use_error>

Need to read the generated files first before overwriting them.

Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv.gleam"
}
     1→import gleam/io
     2→
     3→pub fn main() -> Nil {
     4→  io.println("Hello from raft_kv!")
     5→}
     6→
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/raft_kv/test/raft_kv_test.gleam"
}
     1→import gleeunit
     2→
     3→pub fn main() -> Nil {
     4→  gleeunit.main()
     5→}
     6→
     7→// gleeunit test functions end in `_test`
     8→pub fn hello_world_test() {
     9→  let name = "Joe"
    10→  let greeting = "Hello, " <> name <> "!"
    11→
    12→  assert greeting == "Hello, Joe!"
    13→}
    14→
📝 Write raft_kv.gleam
/Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv.gleam
import argv
import gleam/bit_array
import gleam/erlang/process
import gleam/int
import gleam/io
import gleam/list
import gleam/result
import raft_kv/client
import raft_kv/node
import tom

/// Helper to create a list [1, 2, ..., n]
fn range_list(n: Int) -> List(Int) {
  int.range(1, n + 1, [], fn(acc, i) { [i, ..acc] })
  |> list.reverse
}

/// Read a file as a string (using Erlang's file module)
@external(erlang, "file", "read_file")
fn do_read_file(path: String) -> Result(BitArray, dynamic)

fn read_file(path: String) -> Result(String, Nil) {
  case do_read_file(path) {
    Ok(bits) -> bit_array.to_string(bits) |> result.nil_error
    Error(_) -> Error(Nil)
  }
}

/// Read the config file and return (num_nodes, num_clients)
fn read_config(path: String) -> #(Int, Int) {
  let assert Ok(content) = read_file(path)
  let assert Ok(parsed) = tom.parse(content)

  let num_nodes =
    tom.get_int(parsed, ["num_nodes"])
    |> result.unwrap(5)

  let num_clients =
    tom.get_int(parsed, ["num_clients"])
    |> result.unwrap(3)

  #(num_nodes, num_clients)
}

pub fn main() -> Nil {
  // Determine config file path from args or default
  let config_path = case argv.load().arguments {
    [path, ..] -> path
    [] -> "config.toml"
  }

  let #(num_nodes, num_clients) = read_config(config_path)
  io.println(
    "Config: "
    <> int.to_string(num_nodes)
    <> " nodes, "
    <> int.to_string(num_clients)
    <> " clients",
  )

  // Start N Raft nodes
  let nodes =
    range_list(num_nodes)
    |> list.map(fn(i) {
      let assert Ok(n) = node.start(i, num_nodes)
      io.println("Started node " <> int.to_string(i))
      #(i, n)
    })

  // Send SetPeers to each node with all other nodes
  list.each(nodes, fn(node_pair) {
    let #(id, subject) = node_pair
    let peers = list.filter(nodes, fn(p) { p.0 != id })
    process.send(subject, node.SetPeers(peers))
  })
  io.println("All peers configured")

  // Trigger election on node 1
  let assert Ok(#(_, leader_subject)) =
    list.find(nodes, fn(n) { n.0 == 1 })
  process.send(leader_subject, node.StartElection)

  // Small sleep to let election complete
  process.sleep(200)
  io.println("Election complete, starting clients")

  // Start clients targeting node 1 (the leader)
  let clients =
    range_list(num_clients)
    |> list.map(fn(i) {
      let assert Ok(c) = client.start(leader_subject)
      io.println("Started client " <> int.to_string(i))
      c
    })

  // Tell each client to begin sending requests
  list.each(clients, fn(c) { process.send(c, client.Start) })
  io.println(
    "All " <> int.to_string(num_clients) <> " clients started sending requests",
  )

  // Wait for clients to finish
  process.sleep(3000)
  io.println("Done")
}
The file /Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv.gleam has been updated successfully.
📝 Write raft_kv_test.gleam
/Users/apanda/code/agent-spec-code/raft_kv/test/raft_kv_test.gleam
import gleam/erlang/process
import gleeunit
import raft_kv/node
import raft_kv/types

pub fn main() -> Nil {
  gleeunit.main()
}

pub fn raft_put_get_test() {
  // Start 3 nodes
  let assert Ok(n1) = node.start(1, 3)
  let assert Ok(n2) = node.start(2, 3)
  let assert Ok(n3) = node.start(3, 3)

  // Configure peers
  process.send(n1, node.SetPeers([#(2, n2), #(3, n3)]))
  process.send(n2, node.SetPeers([#(1, n1), #(3, n3)]))
  process.send(n3, node.SetPeers([#(1, n1), #(2, n2)]))

  // Elect node 1 as leader
  process.send(n1, node.StartElection)
  process.sleep(100)

  // Test KV operations
  let assert types.OpOk = node.put(n1, "x", "hello")
  let assert Ok("hello") = node.get(n1, "x")
  let assert types.OpError(_) = node.put(n1, "x", "world")
  let assert types.OpOk = node.delete(n1, "x")
  let assert Error(_) = node.get(n1, "x")
  let assert types.OpError(_) = node.delete(n1, "x")
}
The file /Users/apanda/code/agent-spec-code/raft_kv/test/raft_kv_test.gleam has been updated successfully.

Now let me build and see if there are any compilation errors.

$ Bash
Build raft_kv project
gleam build 2>&1
Exit code 1
  Compiling argv
  Compiling gleam_stdlib
  Compiling gleam_erlang
  Compiling gleam_otp
  Compiling gleam_time
  Compiling gleeunit
  Compiling tom
  Compiling raft_kv
error: Unknown module value
   ┌─ /Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv.gleam:24:53
   │
24 │     Ok(bits) -> bit_array.to_string(bits) |> result.nil_error
   │                                                     ^^^^^^^^^ Did you mean `is_error`?

The module `gleam/result` does not have a `nil_error` value.
✏️ Edit raft_kv.gleam
/Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv.gleam
    Ok(bits) -> bit_array.to_string(bits) |> result.nil_error
+
    Ok(bits) ->
      case bit_array.to_string(bits) {
        Ok(s) -> Ok(s)
        Error(_) -> Error(Nil)
      }
The file /Users/apanda/code/agent-spec-code/raft_kv/src/raft_kv.gleam has been updated successfully.
$ Bash
Build raft_kv project
gleam build 2>&1
  Compiling raft_kv
   Compiled in 0.33s

Builds successfully. Let me run the tests.

$ Bash
Run raft_kv tests
gleam test 2>&1
   Compiled in 0.02s
    Running raft_kv_test.main
[node 1] Starting
[node 2] Starting
[node 3] Starting
[node 3] Peers configured (2 peers)
[node 2] Peers configured (2 peers)
[node 1] Peers configured (2 peers)
[node 1] Starting election for term 1
[node 2] Granting vote to 1 for term 1
[node 1] Received vote from node 2
[node 3] Granting vote to 1 for term 1
[node 1] Received vote from node 3
[node 1] Election result: 3 votes (need 2)
[node 1] Became LEADER for term 1
[node 1] Appending entry at index 1 (term 1)
[node 2] AppendEntries OK from leader 1, match_index=1
[node 1] AppendEntries ACK from node 2 (match=1)
[node 3] AppendEntries OK from leader 1, match_index=1
[node 1] AppendEntries ACK from node 3 (match=1)
[node 1] Replication: 3/2 acks
[node 1] PUT "x" = "hello" -> OK
[node 2] CommitNotification: commit_index updated to 1
[node 3] CommitNotification: commit_index updated to 1
[node 1] Appending entry at index 2 (term 1)
[node 2] slot 1: PUT "x" = "hello" -> OK
[node 3] slot 1: PUT "x" = "hello" -> OK
[node 2] AppendEntries OK from leader 1, match_index=2
[node 1] AppendEntries ACK from node 2 (match=2)
[node 3] AppendEntries OK from leader 1, match_index=2
[node 1] AppendEntries ACK from node 3 (match=2)
[node 1] Replication: 3/2 acks
[node 1] GET "x" -> "hello"
[node 2] CommitNotification: commit_index updated to 2
[node 3] CommitNotification: commit_index updated to 2
[node 1] Appending entry at index 3 (term 1)
[node 2] slot 2: GET "x" -> "hello"
[node 3] slot 2: GET "x" -> "hello"
[node 2] AppendEntries OK from leader 1, match_index=3
[node 1] AppendEntries ACK from node 2 (match=3)
[node 3] AppendEntries OK from leader 1, match_index=3
[node 1] AppendEntries ACK from node 3 (match=3)
[node 1] Replication: 3/2 acks
[node 1] PUT "x" -> REJECTED (key exists)
[node 2] CommitNotification: commit_index updated to 3
[node 3] CommitNotification: commit_index updated to 3
[node 1] Appending entry at index 4 (term 1)
[node 2] slot 3: PUT "x" -> REJECTED (key exists)
[node 3] slot 3: PUT "x" -> REJECTED (key exists)
[node 2] AppendEntries OK from leader 1, match_index=4
[node 1] AppendEntries ACK from node 2 (match=4)
[node 3] AppendEntries OK from leader 1, match_index=4
[node 1] AppendEntries ACK from node 3 (match=4)
[node 1] Replication: 3/2 acks
[node 1] DELETE "x" -> OK
[node 2] CommitNotification: commit_index updated to 4
[node 3] CommitNotification: commit_index updated to 4
[node 1] Appending entry at index 5 (term 1)
[node 2] slot 4: DELETE "x" -> OK
[node 3] slot 4: DELETE "x" -> OK
[node 2] AppendEntries OK from leader 1, match_index=5
[node 1] AppendEntries ACK from node 2 (match=5)
[node 3] AppendEntries OK from leader 1, match_index=5
[node 1] AppendEntries ACK from node 3 (match=5)
[node 1] Replication: 3/2 acks
[node 1] GET "x" -> NOT FOUND
[node 2] CommitNotification: commit_index updated to 5
[node 3] CommitNotification: commit_index updated to 5
[node 1] Appending entry at index 6 (term 1)
[node 2] slot 5: GET "x" -> NOT FOUND
[node 3] slot 5: GET "x" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=6
[node 1] AppendEntries ACK from node 2 (match=6)
[node 3] AppendEntries OK from leader 1, match_index=6
[node 1] AppendEntries ACK from node 3 (match=6)
[node 1] Replication: 3/2 acks
[node 1] DELETE "x" -> NOT FOUND
[node 2] CommitNotification: commit_index updated to 6
[node 3] CommitNotification: commit_index updated to 6
.
1 passed, no failures

All tests pass. Now let me run the full program and format the code.

$ Bash
Format raft_kv code
gleam format 2>&1
$ Bash
Run raft_kv with default config
gleam run 2>&1
  Compiling raft_kv
   Compiled in 0.28s
    Running raft_kv.main
Config: 5 nodes, 3 clients
[node 1] Starting
Started node 1
[node 2] Starting
Started node 2
[node 3] Starting
Started node 3
[node 4] Starting
Started node 4
[node 5] Starting
Started node 5
All peers configured
[node 1] Peers configured (4 peers)
[node 2] Peers configured (4 peers)
[node 3] Peers configured (4 peers)
[node 4] Peers configured (4 peers)
[node 5] Peers configured (4 peers)
[node 1] Starting election for term 1
[node 2] Granting vote to 1 for term 1
[node 1] Received vote from node 2
[node 3] Granting vote to 1 for term 1
[node 1] Received vote from node 3
[node 4] Granting vote to 1 for term 1
[node 1] Received vote from node 4
[node 5] Granting vote to 1 for term 1
[node 1] Received vote from node 5
[node 1] Election result: 5 votes (need 3)
[node 1] Became LEADER for term 1
Election complete, starting clients
Started client 1
Started client 2
Started client 3
All 3 clients started sending requests
[client] Starting — will send 5 requests
[client] Starting — will send 5 requests
[client] Starting — will send 5 requests
[node 1] Appending entry at index 1 (term 1)
[node 2] AppendEntries OK from leader 1, match_index=1
[node 1] AppendEntries ACK from node 2 (match=1)
[node 3] AppendEntries OK from leader 1, match_index=1
[node 1] AppendEntries ACK from node 3 (match=1)
[node 4] AppendEntries OK from leader 1, match_index=1
[node 1] AppendEntries ACK from node 4 (match=1)
[node 5] AppendEntries OK from leader 1, match_index=1
[node 1] AppendEntries ACK from node 5 (match=1)
[node 1] Replication: 5/3 acks
[node 1] DELETE "a" -> NOT FOUND
[node 1] Appending entry at index 2 (term 1)
[client] DELETE "a" -> key not found: a
[node 2] CommitNotification: commit_index updated to 1
[node 3] CommitNotification: commit_index updated to 1
[node 4] CommitNotification: commit_index updated to 1
[node 5] CommitNotification: commit_index updated to 1
[node 2] slot 1: DELETE "a" -> NOT FOUND
[node 3] slot 1: DELETE "a" -> NOT FOUND
[node 4] slot 1: DELETE "a" -> NOT FOUND
[node 5] slot 1: DELETE "a" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=2
[node 1] AppendEntries ACK from node 2 (match=2)
[node 3] AppendEntries OK from leader 1, match_index=2
[node 1] AppendEntries ACK from node 3 (match=2)
[node 4] AppendEntries OK from leader 1, match_index=2
[node 1] AppendEntries ACK from node 4 (match=2)
[node 5] AppendEntries OK from leader 1, match_index=2
[node 1] AppendEntries ACK from node 5 (match=2)
[node 1] Replication: 5/3 acks
[node 1] PUT "b" = "val_84" -> OK
[node 1] Appending entry at index 3 (term 1)
[client] PUT "b" = "val_84" -> OK
[node 2] CommitNotification: commit_index updated to 2
[node 3] CommitNotification: commit_index updated to 2
[node 4] CommitNotification: commit_index updated to 2
[node 5] CommitNotification: commit_index updated to 2
[node 2] slot 2: PUT "b" = "val_84" -> OK
[node 3] slot 2: PUT "b" = "val_84" -> OK
[node 4] slot 2: PUT "b" = "val_84" -> OK
[node 5] slot 2: PUT "b" = "val_84" -> OK
[node 2] AppendEntries OK from leader 1, match_index=3
[node 1] AppendEntries ACK from node 2 (match=3)
[node 3] AppendEntries OK from leader 1, match_index=3
[node 1] AppendEntries ACK from node 3 (match=3)
[node 4] AppendEntries OK from leader 1, match_index=3
[node 1] AppendEntries ACK from node 4 (match=3)
[node 5] AppendEntries OK from leader 1, match_index=3
[node 1] AppendEntries ACK from node 5 (match=3)
[node 1] Replication: 5/3 acks
[node 1] DELETE "e" -> NOT FOUND
[node 1] Appending entry at index 4 (term 1)
[client] DELETE "e" -> key not found: e
[node 2] CommitNotification: commit_index updated to 3
[node 3] CommitNotification: commit_index updated to 3
[node 4] CommitNotification: commit_index updated to 3
[node 5] CommitNotification: commit_index updated to 3
[node 2] slot 3: DELETE "e" -> NOT FOUND
[node 3] slot 3: DELETE "e" -> NOT FOUND
[node 4] slot 3: DELETE "e" -> NOT FOUND
[node 5] slot 3: DELETE "e" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=4
[node 1] AppendEntries ACK from node 2 (match=4)
[node 3] AppendEntries OK from leader 1, match_index=4
[node 1] AppendEntries ACK from node 3 (match=4)
[node 4] AppendEntries OK from leader 1, match_index=4
[node 1] AppendEntries ACK from node 4 (match=4)
[node 5] AppendEntries OK from leader 1, match_index=4
[node 1] AppendEntries ACK from node 5 (match=4)
[node 1] Replication: 5/3 acks
[node 1] GET "e" -> NOT FOUND
[node 1] Appending entry at index 5 (term 1)
[client] GET "e" -> key not found: e
[node 2] CommitNotification: commit_index updated to 4
[node 3] CommitNotification: commit_index updated to 4
[node 4] CommitNotification: commit_index updated to 4
[node 5] CommitNotification: commit_index updated to 4
[node 2] slot 4: GET "e" -> NOT FOUND
[node 3] slot 4: GET "e" -> NOT FOUND
[node 4] slot 4: GET "e" -> NOT FOUND
[node 5] slot 4: GET "e" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=5
[node 1] AppendEntries ACK from node 2 (match=5)
[node 3] AppendEntries OK from leader 1, match_index=5
[node 1] AppendEntries ACK from node 3 (match=5)
[node 4] AppendEntries OK from leader 1, match_index=5
[node 1] AppendEntries ACK from node 4 (match=5)
[node 5] AppendEntries OK from leader 1, match_index=5
[node 1] AppendEntries ACK from node 5 (match=5)
[node 1] Replication: 5/3 acks
[node 1] PUT "b" -> REJECTED (key exists)
[node 1] Appending entry at index 6 (term 1)
[client] PUT "b" = "val_55" -> key already exists: b
[node 2] CommitNotification: commit_index updated to 5
[node 3] CommitNotification: commit_index updated to 5
[node 4] CommitNotification: commit_index updated to 5
[node 5] CommitNotification: commit_index updated to 5
[node 2] slot 5: PUT "b" -> REJECTED (key exists)
[node 3] slot 5: PUT "b" -> REJECTED (key exists)
[node 4] slot 5: PUT "b" -> REJECTED (key exists)
[node 5] slot 5: PUT "b" -> REJECTED (key exists)
[node 2] AppendEntries OK from leader 1, match_index=6
[node 1] AppendEntries ACK from node 2 (match=6)
[node 3] AppendEntries OK from leader 1, match_index=6
[node 1] AppendEntries ACK from node 3 (match=6)
[node 4] AppendEntries OK from leader 1, match_index=6
[node 1] AppendEntries ACK from node 4 (match=6)
[node 5] AppendEntries OK from leader 1, match_index=6
[node 1] AppendEntries ACK from node 5 (match=6)
[node 1] Replication: 5/3 acks
[node 1] GET "e" -> NOT FOUND
[node 1] Appending entry at index 7 (term 1)
[client] GET "e" -> key not found: e
[node 2] CommitNotification: commit_index updated to 6
[node 3] CommitNotification: commit_index updated to 6
[node 4] CommitNotification: commit_index updated to 6
[node 5] CommitNotification: commit_index updated to 6
[node 2] slot 6: GET "e" -> NOT FOUND
[node 3] slot 6: GET "e" -> NOT FOUND
[node 4] slot 6: GET "e" -> NOT FOUND
[node 5] slot 6: GET "e" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=7
[node 1] AppendEntries ACK from node 2 (match=7)
[node 3] AppendEntries OK from leader 1, match_index=7
[node 1] AppendEntries ACK from node 3 (match=7)
[node 4] AppendEntries OK from leader 1, match_index=7
[node 1] AppendEntries ACK from node 4 (match=7)
[node 5] AppendEntries OK from leader 1, match_index=7
[node 1] AppendEntries ACK from node 5 (match=7)
[node 1] Replication: 5/3 acks
[node 1] DELETE "b" -> OK
[node 1] Appending entry at index 8 (term 1)
[client] DELETE "b" -> OK
[node 2] CommitNotification: commit_index updated to 7
[node 3] CommitNotification: commit_index updated to 7
[node 4] CommitNotification: commit_index updated to 7
[node 5] CommitNotification: commit_index updated to 7
[node 2] slot 7: DELETE "b" -> OK
[node 3] slot 7: DELETE "b" -> OK
[node 4] slot 7: DELETE "b" -> OK
[node 5] slot 7: DELETE "b" -> OK
[node 2] AppendEntries OK from leader 1, match_index=8
[node 1] AppendEntries ACK from node 2 (match=8)
[node 3] AppendEntries OK from leader 1, match_index=8
[node 1] AppendEntries ACK from node 3 (match=8)
[node 4] AppendEntries OK from leader 1, match_index=8
[node 1] AppendEntries ACK from node 4 (match=8)
[node 5] AppendEntries OK from leader 1, match_index=8
[node 1] AppendEntries ACK from node 5 (match=8)
[node 1] Replication: 5/3 acks
[node 1] PUT "c" = "val_30" -> OK
[client] PUT "c" = "val_30" -> OK
[node 2] CommitNotification: commit_index updated to 8
[node 3] CommitNotification: commit_index updated to 8
[node 4] CommitNotification: commit_index updated to 8
[node 5] CommitNotification: commit_index updated to 8
[node 1] Appending entry at index 9 (term 1)
[node 2] slot 8: PUT "c" = "val_30" -> OK
[node 3] slot 8: PUT "c" = "val_30" -> OK
[node 4] slot 8: PUT "c" = "val_30" -> OK
[node 5] slot 8: PUT "c" = "val_30" -> OK
[node 2] AppendEntries OK from leader 1, match_index=9
[node 1] AppendEntries ACK from node 2 (match=9)
[node 3] AppendEntries OK from leader 1, match_index=9
[node 1] AppendEntries ACK from node 3 (match=9)
[node 4] AppendEntries OK from leader 1, match_index=9
[node 1] AppendEntries ACK from node 4 (match=9)
[node 5] AppendEntries OK from leader 1, match_index=9
[node 1] AppendEntries ACK from node 5 (match=9)
[node 1] Replication: 5/3 acks
[node 1] DELETE "b" -> NOT FOUND
[node 1] Appending entry at index 10 (term 1)
[client] DELETE "b" -> key not found: b
[node 2] CommitNotification: commit_index updated to 9
[node 3] CommitNotification: commit_index updated to 9
[node 4] CommitNotification: commit_index updated to 9
[node 5] CommitNotification: commit_index updated to 9
[node 2] slot 9: DELETE "b" -> NOT FOUND
[node 3] slot 9: DELETE "b" -> NOT FOUND
[node 4] slot 9: DELETE "b" -> NOT FOUND
[node 5] slot 9: DELETE "b" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=10
[node 1] AppendEntries ACK from node 2 (match=10)
[node 3] AppendEntries OK from leader 1, match_index=10
[node 1] AppendEntries ACK from node 3 (match=10)
[node 4] AppendEntries OK from leader 1, match_index=10
[node 1] AppendEntries ACK from node 4 (match=10)
[node 5] AppendEntries OK from leader 1, match_index=10
[node 1] AppendEntries ACK from node 5 (match=10)
[node 1] Replication: 5/3 acks
[node 1] DELETE "c" -> OK
[node 1] Appending entry at index 11 (term 1)
[client] DELETE "c" -> OK
[node 2] CommitNotification: commit_index updated to 10
[node 3] CommitNotification: commit_index updated to 10
[node 4] CommitNotification: commit_index updated to 10
[node 5] CommitNotification: commit_index updated to 10
[node 2] slot 10: DELETE "c" -> OK
[node 3] slot 10: DELETE "c" -> OK
[node 4] slot 10: DELETE "c" -> OK
[node 5] slot 10: DELETE "c" -> OK
[node 2] AppendEntries OK from leader 1, match_index=11
[node 1] AppendEntries ACK from node 2 (match=11)
[node 3] AppendEntries OK from leader 1, match_index=11
[node 1] AppendEntries ACK from node 3 (match=11)
[node 4] AppendEntries OK from leader 1, match_index=11
[node 1] AppendEntries ACK from node 4 (match=11)
[node 5] AppendEntries OK from leader 1, match_index=11
[node 1] AppendEntries ACK from node 5 (match=11)
[node 1] Replication: 5/3 acks
[node 1] DELETE "c" -> NOT FOUND
[node 1] Appending entry at index 12 (term 1)
[client] DELETE "c" -> key not found: c
[node 2] CommitNotification: commit_index updated to 11
[node 3] CommitNotification: commit_index updated to 11
[node 4] CommitNotification: commit_index updated to 11
[node 5] CommitNotification: commit_index updated to 11
[node 2] slot 11: DELETE "c" -> NOT FOUND
[node 3] slot 11: DELETE "c" -> NOT FOUND
[node 4] slot 11: DELETE "c" -> NOT FOUND
[node 5] slot 11: DELETE "c" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=12
[node 1] AppendEntries ACK from node 2 (match=12)
[node 3] AppendEntries OK from leader 1, match_index=12
[node 1] AppendEntries ACK from node 3 (match=12)
[node 4] AppendEntries OK from leader 1, match_index=12
[node 1] AppendEntries ACK from node 4 (match=12)
[node 5] AppendEntries OK from leader 1, match_index=12
[node 1] AppendEntries ACK from node 5 (match=12)
[node 1] Replication: 5/3 acks
[node 1] GET "b" -> NOT FOUND
[node 1] Appending entry at index 13 (term 1)
[client] GET "b" -> key not found: b
[node 2] CommitNotification: commit_index updated to 12
[node 3] CommitNotification: commit_index updated to 12
[node 4] CommitNotification: commit_index updated to 12
[node 5] CommitNotification: commit_index updated to 12
[node 2] slot 12: GET "b" -> NOT FOUND
[node 3] slot 12: GET "b" -> NOT FOUND
[node 4] slot 12: GET "b" -> NOT FOUND
[node 5] slot 12: GET "b" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=13
[node 1] AppendEntries ACK from node 2 (match=13)
[node 3] AppendEntries OK from leader 1, match_index=13
[node 1] AppendEntries ACK from node 3 (match=13)
[node 4] AppendEntries OK from leader 1, match_index=13
[node 1] AppendEntries ACK from node 4 (match=13)
[node 5] AppendEntries OK from leader 1, match_index=13
[node 1] AppendEntries ACK from node 5 (match=13)
[node 1] Replication: 5/3 acks
[node 1] GET "d" -> NOT FOUND
[node 1] Appending entry at index 14 (term 1)
[client] GET "d" -> key not found: d
[node 2] CommitNotification: commit_index updated to 13
[node 3] CommitNotification: commit_index updated to 13
[node 4] CommitNotification: commit_index updated to 13
[node 5] CommitNotification: commit_index updated to 13
[client] Finished all 5 requests
[node 2] slot 13: GET "d" -> NOT FOUND
[node 3] slot 13: GET "d" -> NOT FOUND
[node 4] slot 13: GET "d" -> NOT FOUND
[node 5] slot 13: GET "d" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=14
[node 1] AppendEntries ACK from node 2 (match=14)
[node 3] AppendEntries OK from leader 1, match_index=14
[node 1] AppendEntries ACK from node 3 (match=14)
[node 4] AppendEntries OK from leader 1, match_index=14
[node 1] AppendEntries ACK from node 4 (match=14)
[node 5] AppendEntries OK from leader 1, match_index=14
[node 1] AppendEntries ACK from node 5 (match=14)
[node 1] Replication: 5/3 acks
[node 1] DELETE "b" -> NOT FOUND
[node 1] Appending entry at index 15 (term 1)
[client] DELETE "b" -> key not found: b
[node 2] CommitNotification: commit_index updated to 14
[node 3] CommitNotification: commit_index updated to 14
[node 4] CommitNotification: commit_index updated to 14
[node 5] CommitNotification: commit_index updated to 14
[client] Finished all 5 requests
[node 2] slot 14: DELETE "b" -> NOT FOUND
[node 3] slot 14: DELETE "b" -> NOT FOUND
[node 4] slot 14: DELETE "b" -> NOT FOUND
[node 5] slot 14: DELETE "b" -> NOT FOUND
[node 2] AppendEntries OK from leader 1, match_index=15
[node 1] AppendEntries ACK from node 2 (match=15)
[node 3] AppendEntries OK from leader 1, match_index=15
[node 1] AppendEntries ACK from node 3 (match=15)
[node 4] AppendEntries OK from leader 1, match_index=15
[node 1] AppendEntries ACK from node 4 (match=15)
[node 5] AppendEntries OK from leader 1, match_index=15
[node 1] AppendEntries ACK from node 5 (match=15)
[node 1] Replication: 5/3 acks
[node 1] GET "a" -> NOT FOUND
[client] GET "a" -> key not found: a
[node 2] CommitNotification: commit_index updated to 15
[node 3] CommitNotification: commit_index updated to 15
[node 4] CommitNotification: commit_index updated to 15
[node 5] CommitNotification: commit_index updated to 15
[client] Finished all 5 requests
[node 2] slot 15: GET "a" -> NOT FOUND
[node 3] slot 15: GET "a" -> NOT FOUND
[node 4] slot 15: GET "a" -> NOT FOUND
[node 5] slot 15: GET "a" -> NOT FOUND
Done

Everything works. Here's a summary of what was created:

Raft KV Store Emulation

Files created in raft_kv/:

File Description
config.toml Default config: 5 nodes, 3 clients
src/raft_kv.gleam Main entry: reads TOML config, starts nodes, triggers election, runs clients
src/raft_kv/types.gleam Shared types: Command, OpResult, LogEntry
src/raft_kv/node.gleam Raft node actor — handles election (RequestVote), log replication (AppendEntries), commit notifications, and client requests (put/get/delete)
src/raft_kv/client.gleam Client actor — sends 5 random requests to the leader
test/raft_kv_test.gleam Tests: put, get existing, put duplicate (error), delete, get missing, delete missing (error)

Verification results: - gleam build — compiles cleanly - gleam test — 1 test passed (KV semantics verified) - gleam run — 5 nodes start, node 1 wins election, 3 clients issue requests with full Raft replication trace, followers apply committed entries - gleam format — code is formatted

The code does not seem to include heartbeats, nor an election timeout. Can you check if I am mistaken about this, and if so point me to where they are?

You're correct — the implementation has neither heartbeats nor election timeouts. Node 1's election is triggered explicitly by main via a StartElection message, and there's no periodic heartbeat from the leader to followers. This works for the emulation (since there are no failures), but these are core Raft mechanisms that are missing.

Can you record that this is the case in the readme file. Include your reasoning too.

Glob
{
  "pattern": "raft_kv/README.md"
}
/Users/apanda/code/agent-spec-code/raft_kv/README.md
Read
{
  "file_path": "/Users/apanda/code/agent-spec-code/raft_kv/README.md"
}
     1→# raft_kv
     2→
     3→[![Package Version](https://img.shields.io/hexpm/v/raft_kv)](https://hex.pm/packages/raft_kv)
     4→[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/raft_kv/)
     5→
     6→```sh
     7→gleam add raft_kv@1
     8→```
     9→```gleam
    10→import raft_kv
    11→
    12→pub fn main() -> Nil {
    13→  // TODO: An example of the project in use
    14→}
    15→```
    16→
    17→Further documentation can be found at <https://hexdocs.pm/raft_kv>.
    18→
    19→## Development
    20→
    21→```sh
    22→gleam run   # Run the project
    23→gleam test  # Run the tests
    24→```
    25→
📝 Write README.md
/Users/apanda/code/agent-spec-code/raft_kv/README.md
# raft_kv

An emulation of a replicated key-value store using the Raft consensus protocol, implemented in Gleam with OTP actors.

## Running

```sh
gleam run              # Run with default config (config.toml)
gleam run -- path.toml # Run with a custom config file
gleam test             # Run the tests
```

## Configuration

Edit `config.toml` to set the number of nodes and clients:

```toml
num_nodes = 5
num_clients = 3
```

## Simplifications

This emulation omits **heartbeats** and **election timeouts**, which are core mechanisms in the full Raft protocol. In real Raft:

- The leader periodically sends empty AppendEntries RPCs (heartbeats) to followers to maintain authority and prevent new elections.
- Followers start a new election if they don't receive a heartbeat within a randomized election timeout, which is how the system recovers from leader failure.

These are omitted here because this is a failure-free emulation: the leader is designated at startup (node 1 sends a single `StartElection` message and wins), no nodes crash, and there is no need for leader recovery. Including heartbeats and election timeouts would add complexity without changing the observable behavior of the emulation. The focus is on demonstrating Raft's log replication and commit mechanics rather than its leader election recovery path.
The file /Users/apanda/code/agent-spec-code/raft_kv/README.md has been updated successfully.

Done. The README now documents the omission of heartbeats and election timeouts, along with the reasoning: this is a failure-free emulation focused on log replication mechanics, so leader recovery isn't needed.

Can you create a commit with all of this.

$ Bash
Show working tree status
cd /Users/apanda/code/agent-spec-code && git status -u
$ Bash
Show diff stats for staged/unstaged changes
cd /Users/apanda/code/agent-spec-code && git diff --stat
$ Bash
Show recent commit messages
cd /Users/apanda/code/agent-spec-code && git log --oneline -5
The user doesn't want to proceed with this tool use. The tool use was rejected (eg. if it was a file edit, the new_string was NOT written to the file). STOP what you are doing and wait for the user to tell you how to proceed.
The user doesn't want to proceed with this tool use. The tool use was rejected (eg. if it was a file edit, the new_string was NOT written to the file). STOP what you are doing and wait for the user to tell you how to proceed.
The user doesn't want to proceed with this tool use. The tool use was rejected (eg. if it was a file edit, the new_string was NOT written to the file). STOP what you are doing and wait for the user to tell you how to proceed.