Claude Code transcript - page 1/2

     1→import Veil
     2→
     3→veil module RingFin
     4→
     5→type node
     6→-- This allows us to use the `≤` notation
     7→instantiate inst : LE node
     8→instantiate decLE : DecidableRel inst.le
     9→-- This allows us to insert into the messages list in order
    10→instantiate ord : Ord node
    11→
    12→immutable function nextNode : node → node
    13→
    14→individual leader : List node
    15→
    16→@[veil_decl] structure Message (node : Type) where
    17→  payload : node
    18→  src : node
    19→  dst : node
    20→
    21→individual messages : List (Message node)
    22→
    23→#gen_state
    24→
    25→after_init {
    26→  leader := []
    27→  messages := []
    28→}
    29→
    30→procedure sendToNext (payload src : node) {
    31→  let msg := Message.mk payload src (nextNode src)
    32→  if msg ∉ messages then
    33→    messages := messages.insertOrdered msg
    34→}
    35→
    36→action send (n : node) {
    37→  sendToNext n n
    38→}
    39→
    40→action recv {
    41→  let m :| m ∈ messages
    42→  let n := m.dst
    43→  messages := messages.erase m
    44→  if m.payload = n && n ∉ leader then
    45→    leader := n :: leader
    46→  else
    47→    if n ≤ m.payload then
    48→      sendToNext m.payload n
    49→}
    50→
    51→safety [single_leader] leader.length ≤ 1
    52→invariant [messages_nodup] messages.Nodup
    53→
    54→#gen_spec
    55→
    56→#model_check { node := Fin 4 } { nextNode := fun n => n + 1 }
    57→
    58→end RingFin
    59→

Perfect! Now I have a comprehensive understanding of the Veil DSL patterns. Let me compile my findings into a clear report.

## Veil DSL Pattern Understanding Report

Based on my analysis of several example specifications, here's a comprehensive guide to understanding the Veil DSL patterns:

### 1. **State Declaration (Relations, Functions, Individuals)**

**Relations** (predicates over parameters):
```lean
relation leader : node → Bool
relation pending : node → node → Bool
relation initial_msg (originator : address) (dst : address) (r : round) (v : value)
```
- Used for multi-parameter state that can be true/false for specific inputs
- Support arbitrary arities (1, 2, 3+ parameters)
- In model checking, represented as sets of tuples

**Functions** (parameterized state):
```lean
function rmState (r : RM) : RMStateType
function epoch : node -> time
```
- Map parameters to specific values
- Can return enums, integers, or other types
- Often used for per-node state with values from enums

**Individuals** (global state):
```lean
individual leader : List node
individual messages : List (Message node)
individual tmState : TMStateType
individual msgCommit : Bool
```
- Single global values (not parameterized)
- Can be lists, booleans, or custom types
- Used for consensus/global state tracking

**Immutable state** (constants):
```lean
immutable function nextNode : node → node
immutable relation le : time -> time -> Bool
immutable individual first : node
```
- Constants defined at module initialization
- Passed to model checker as concrete values
- Used for topology, ordering relations, etc.

---

### 2. **Actions/Procedures**

**Basic action structure**:
```lean
action recv {
  let m :| m ∈ messages
  let n := m.dst
  messages := messages.erase m
  if m.payload = n && n ∉ leader then
    leader := n :: leader
  else
    if n ≤ m.payload then
      sendToNext m.payload n
}
```

**Action with parameters**:
```lean
action recv (sender n next : node) {
  require isNext n next
  require pending sender n
  pending sender n := false
  if (sender = n) then
    leader n := true
  else
    if (le n sender) then
      pending sender next := true
}
```

**Procedure (reusable helper)**:
```lean
procedure sendToNext (payload src : node) {
  let msg := Message.mk payload src (nextNode src)
  if msg ∉ messages then
    messages := messages.insertOrdered msg
}
```

**Key constructs**:
- `require` — precondition (enables action only if true)
- `let x := expr` — local variable binding
- `let x :| condition` — existential binding (nondeterministic choice)
- Assignment with `:=` for both individuals and relations
- `if/else` for conditionals
- Pattern matching with `|` in destructuring

**Transition blocks** (used for Byzantine faults):
```lean
transition byz {
  (∀ (src dst : address), ...
    (¬ is_byz src ∧ (initial_msg src dst r v ↔ initial_msg' src dst r v)) ∨
    (is_byz src ∧ (initial_msg src dst r v → initial_msg' src dst r v)))
}
```

---

### 3. **Invariants and Safety Properties**

**Safety property** (must never be violated):
```lean
safety [single_leader] leader.length ≤ 1
safety [vote_integrity]
  ∀ (src dst : address) (r : round) (v : value),
     ¬ is_byz src ∧ ¬ is_byz dst ∧ voted dst src r v → (sent src r ∧ initial_value src r v)
```

**Invariant** (must be true in all reachable states):
```lean
invariant [messages_nodup] messages.Nodup
invariant [leader_greatest] leader L → le N L
invariant [drop_smaller] pending S D ∧ btw S N D → le N S
```

**Assumption** (constraint on initial state):
```lean
assumption ∀ (x: time), le x X
assumption ∀ (x y z : time), le x y ∧ le y z → le x z
```

**Ghost relations** (derived state for specification only):
```lean
ghost relation isNext (n : node) (next : node) :=
  ∀ Z, n ≠ next ∧ ((Z ≠ n ∧ Z ≠ next) → btw n next Z)

ghost relation initial_value (n : address) (r : round) (v : value) := 
  ∀ dst, initial_msg n dst r v
```

---

### 4. **#gen_state and #gen_spec**

**#gen_state** (after line 14-32 in examples):
- Generates the state type from declared relations, functions, and individuals
- Must come after type/enum/relation/individual/function declarations
- Initializes metadata and internal structures
- No arguments needed

**#gen_spec** (after line 45-54 in examples):
- Generates the specification from actions and properties
- Creates verification conditions for invariants
- Orchestrates SMT solver and model checking
- Should come after all actions, invariants, and safety properties

**Usage order**:
```
type declarations → instantiate → relation/function/individual → #gen_state 
→ after_init → procedures → actions → safety/invariant/assumption → #gen_spec
→ #model_check / sat trace / unsat trace / #check_invariants
```

---

### 5. **Type Declaration Patterns**

**Abstract types** (no structure):
```lean
type node
type RM
type address
```

**Type classes and instances** (for ordering, comparison):
```lean
type node
instantiate inst : LE node
instantiate decLE : DecidableRel inst.le
instantiate ord : Ord node

-- Or use TotalOrder (provides everything)
instantiate tot : TotalOrder node
```

**Enum types** (discrete values):
```lean
enum RMStateType = { working, prepared, committed, aborted }
enum TMStateType = { init, tmCommitted, tmAborted }
```

**Custom structures**:
```lean
@[veil_decl] structure Message (node : Type) where
  payload : node
  src : node
  dst : node
```

**Instantiating specialized type classes**:
```lean
instantiate nset : ByzNodeSet address nodeset
open ByzNodeSet
```

---

### 6. **Model Checking and Verification**

**Model checking** (concrete instantiation):
```lean
#model_check { node := Fin 4 } { nextNode := fun n => n + 1 }
#model_check { RM := Fin 3 }
#model_check { 
  nodeset := ByzNSet (3 * 1 + 1)
  address := Fin (3 * 1 + 1)
  round := Fin 3
  value := Fin 3 
}
```

**Trace checking** (existential test):
```lean
sat trace {
  any 3 actions
  assert (∃ l, leader l)
}

unsat trace {
  any 5 actions
  assert (∃ n₁ n₂, n₁ ≠ n₂ ∧ leader n₁ ∧ leader n₂)
}
```

**Invariant checking**:
```lean
#check_invariants
```

**Timing**:
```lean
#time #gen_spec
```

---

### 7. **after_init Block**

Initializes all mutable state to starting values:
```lean
after_init {
  leader := []
  messages := []
}

after_init {
  leader N := false
  pending M N := false
}

after_init {
  rmState R := working
  tmState := init
  tmPrepared R := false
  msgPrepared R := false
  msgCommit := false
  msgAbort := false
}
```

---

### Example Files Reviewed

1. **`/Users/apanda/code/agent-spec/veil/Examples/Tutorial/RingFin.lean`** (59 lines) — Simple ring leader election with messages, demonstrates individual + relation state with after_init and model checking
   
2. **`/Users/apanda/code/agent-spec/veil/Examples/Ivy/Ring.lean`** (62 lines) — Leader election using relations, ghost relations, and parametric state
   
3. **`/Users/apanda/code/agent-spec/veil/Examples/TLA/TwoPhaseCommit.lean`** (222 lines) — Complex distributed protocol with functions, enums, multiple coordinated nodes (TM + RMs)
   
4. **`/Users/apanda/code/agent-spec/veil/Examples/Ivy/ReliableBroadcast.lean`** (211 lines) — Byzantine-tolerant broadcast with quorum structures, multiple message types, ghost relations
   
5. **`/Users/apanda/code/agent-spec/veil/Examples/Ivy/DecentralizedLock.lean`** (61 lines) — Simpler protocol with immutable relations and assumptions, mutex safety property

---

### Directory Structure

- **`/Users/apanda/code/agent-spec/veil/Examples/apanda/`** — Already created and empty, ready for your new examples
- Examples follow the pattern: `import Veil` then `veil module ModuleName ... end ModuleName`

This gives you a complete foundation for creating your own Veil specifications!

agentId: a3e8bd92b414bd65e (for resuming to continue this agent's work if needed)
<usage>total_tokens: 26753
tool_uses: 8
duration_ms: 33647</usage>

---
apanda
Ivy
Puzzles
README.md
Synchronous
TLA
Tutorial

File created successfully at: /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean

     1→import Veil
     2→
     3→veil module MaxCounter
     4→
     5→-- Server and client node types
     6→type server
     7→type client
     8→
     9→-- Each server maintains an integer counter value
    10→function counter : server → Int
    11→
    12→#gen_state
    13→
    14→-- Initially all counters are zero
    15→after_init {
    16→  counter S := 0
    17→}
    18→
    19→-- A client sets a server's counter to a new value,
    20→-- but only if the new value is strictly larger than the current one.
    21→action clientSet (c : client) (s : server) (v : Int) {
    22→  require v > counter s
    23→  counter s := v
    24→}
    25→
    26→-- A client reads a server's counter (no state change).
    27→-- Modeled as a no-op action since gets don't modify state.
    28→action clientGet (c : client) (s : server) {
    29→  require True
    30→}
    31→
    32→-- Two servers synchronize: the destination server adopts the
    33→-- source server's value if it is larger. This models periodic
    34→-- pairwise synchronization.
    35→action serverSync (src dst : server) {
    36→  require src ≠ dst
    37→  if counter src > counter dst then
    38→    counter dst := counter src
    39→}
    40→
    41→-- Safety: no server's counter ever decreases below any value it has held.
    42→-- Stated as: all counters are non-negative (since they start at 0 and
    43→-- can only increase).
    44→safety [counters_nonneg] ∀ (s : server), counter s ≥ 0
    45→
    46→-- Safety: after synchronization, the destination server's counter is
    47→-- at least as large as the source server's counter.
    48→-- This is captured by the invariant that no synchronization can make
    49→-- a counter decrease.
    50→
    51→-- Key convergence-related invariant: the maximum counter value across
    52→-- all servers never decreases. We express a supporting invariant:
    53→-- for any two servers, after a sync between them, the smaller counter
    54→-- can only go up (never down). This is inherent in the transition
    55→-- system but we state a checkable safety property.
    56→
    57→-- The core consistency property: if two servers have synchronized
    58→-- (directly or transitively), they agree. We can check a simpler
    59→-- property: no action ever decreases any server's counter.
    60→invariant [monotone] ∀ (s : server), counter s ≥ 0
    61→
    62→#gen_spec
    63→
    64→-- Model check with a small number of servers and clients
    65→#model_check { server := Fin 3, client := Fin 2 }
    66→
    67→end MaxCounter
    68→

The file /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean has been updated successfully.

⚠ [736/1171] Replayed Smt.Reconstruct.BitVec.Bitblast
warning: Smt/Reconstruct/BitVec/Bitblast.lean:36:4: declaration uses 'sorry'
⚠ [771/1171] Replayed Smt.Data.Sexp
warning: Smt/Data/Sexp.lean:89:10: `String.next` has been deprecated: Use `String.Pos.Raw.next` instead

Note: The updated constant is in a different namespace. Dot notation may need to be changed (e.g., from `x.next` to `Pos.Raw.next x`).
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:19:5: error: unexpected token 'individual'; expected 'relation'
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:30:18: warning: unused variable `c`

Note: This linter can be disabled with `set_option linter.unusedVariables false`
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:38:18: warning: unused variable `c`

Note: This linter can be disabled with `set_option linter.unusedVariables false`
✅ No violation (explored 9 states)

Examples/Puzzles/Prisoners.lean:34:ghost relation Done := count = 2 * cardPrisoner - 1
Examples/Puzzles/RiverCrossing.lean:22:ghost relation safety_constraint :=
Examples/Ivy/ReliableBroadcast.lean:63:ghost relation initial_value (n : address) (r : round) (v : value) := ∀ dst, initial_msg n dst r v
Examples/apanda/MaxCounter.lean:19:ghost individual maxSet : value
Examples/Ivy/NOPaxos.lean:52:theory ghost relation lt (x y : seq_t) := (seq.le x y ∧ x ≠ y)
Examples/Ivy/NOPaxos.lean:53:theory ghost relation next (x y : seq_t) := (lt x y ∧ ∀ z, lt x z → seq.le y z)
Examples/Tutorial/RingDec.lean:21:ghost relation isNext (n : node) (next : node) :=
Examples/Synchronous/FasterFloodSet.lean:84:ghost relation alive (n : node) := ¬ (nset.contains n dead)
Examples/Ivy/Ring.lean:21:ghost relation isNext (n : node) (next : node) :=
Examples/Synchronous/FloodSet.lean:169:ghost relation allSameSeen :=
Examples/Ivy/MultiSigMajority.lean:29:ghost relation chosenAt (Q:quorum) (N:validator) (K:destination) (V:value) (D:deadline) := ∀ S, member S Q -> sig N K V D S
Examples/Ivy/MultiSigMajority.lean:30:ghost relation chosen (N:validator) (K:destination) (V:value) (D:deadline) := ∃ q, chosenAt q N K V D
Examples/TLA/EWD840.lean:23:theory ghost relation lt (x y : node) := (seq.le x y ∧ x ≠ y)
Examples/TLA/EWD840.lean:24:theory ghost relation next (x y : node) := (lt x y ∧ ∀ z, lt x z → seq.le y z)
Examples/TLA/EWD840.lean:112:ghost relation terminated := ∀i, ¬ active i

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The file /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean has been updated successfully.

warning: Smt/Reconstruct/BitVec/Bitblast.lean:36:4: declaration uses 'sorry'
warning: Smt/Data/Sexp.lean:89:10: `String.next` has been deprecated: Use `String.Pos.Raw.next` instead
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:23:0: error: Error in action initializer: Unknown identifier `_S`
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:30:0: error: Error in action clientSet: Type mismatch
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:37:18: warning: unused variable `c`
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:55:0: error: [Module.declarationSplitParams]: procedure initializer not found
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:58:0: error: The specification of module MaxCounter has not been finalized. Please call #gen_spec first!

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Examples/Puzzles/Prisoners.lean:27:after_init {
Examples/Puzzles/Prisoners.lean-28-  switchAUp := *
Examples/Puzzles/Prisoners.lean-29-  switchBUp := *
Examples/Puzzles/Prisoners.lean-30-  timesSwitched P := if P ≠ Counter then 0 else timesSwitched P
--
Examples/Puzzles/RiverCrossing.lean:26:after_init {
Examples/Puzzles/RiverCrossing.lean-27-  wolf_pos := near
Examples/Puzzles/RiverCrossing.lean-28-  goat_pos := near
Examples/Puzzles/RiverCrossing.lean-29-  cabbage_pos := near
--
Examples/Puzzles/DieHard.lean:11:after_init {
Examples/Puzzles/DieHard.lean-12-  big := 0
Examples/Puzzles/DieHard.lean-13-  small := 0
/Users/apanda/code/agent-spec/veil/Examples/Puzzles/DieHard.lean-14-}
--
Examples/apanda/MaxCounter.lean:23:after_init {
Examples/apanda/MaxCounter.lean-24-  counter _S := default
Examples/apanda/MaxCounter.lean-25-  everSet _V := False
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean-26-}
--
Examples/TLA/EWD840.lean:36:after_init {
/Users/apanda/code/agent-spec/veil/Examples/TLA/EWD840.lean-37-  let S1 ← pick nodesSet
/Users/apanda/code/agent-spec/veil/Examples/TLA/EWD840.lean-38-  let S2 ← pick nodesSet
Examples/TLA/EWD840.lean-39-  active N := if nSet.contains N S1 then true else false
--
Examples/TLA/SimpleAllocator.lean:31:after_init {
Examples/TLA/SimpleAllocator.lean-32-  unsatisfy C := resSet.empty
Examples/TLA/SimpleAllocator.lean-33-  alloc C := resSet.empty
/Users/apanda/code/agent-spec/veil/Examples/TLA/SimpleAllocator.lean-34-}
--

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     1→import Veil
     2→
     3→veil module TwoPhaseCommitTLA
     4→-- ------------------------------- MODULE TwoPhase -----------------------------
     5→-- (***************************************************************************)
     6→-- (* This specification describes the Two-Phase Commit protocol, in which a  *)
     7→-- (* transaction manager (TM) coordinates the resource managers (RMs) to     *)
     8→-- (* implement the Transaction Commit specification of module $TCommit$.  In *)
     9→-- (* this specification, RMs spontaneously issue $Prepared$ messages.  We    *)
    10→-- (* ignore the $Prepare$ messages that the TM can send to the               *)
    11→-- (* RMs.\vspace{.4em}                                                       *)
    12→-- (*                                                                         *)
    13→-- (* For simplicity, we also eliminate $Abort$ messages sent by an RM when   *)
    14→-- (* it decides to abort.  Such a message would cause the TM to abort the    *)
    15→-- (* transaction, an event represented here by the TM spontaneously deciding *)
    16→-- (* to abort.\vspace{.4em}                                                  *)
    17→-- (*                                                                         *)
    18→-- (* This specification describes only the safety properties of the          *)
    19→-- (* protocol--that is, what is allowed to happen.  What must happen would   *)
    20→-- (* be described by liveness properties, which we do not specify.           *)
    21→-- (***************************************************************************)
    22→-- CONSTANT RM \* The set of resource managers
    23→type RM
    24→
    25→-- VARIABLES
    26→--   rmState,       \* $rmState[rm]$ is the state of resource manager RM.
    27→--   tmState,       \* The state of the transaction manager.
    28→--   tmPrepared,    \* The set of RMs from which the TM has received $"Prepared"$
    29→--                  \* messages.
    30→--   msgs
    31→--     (***********************************************************************)
    32→--     (* In the protocol, processes communicate with one another by sending  *)
    33→--     (* messages.  Since we are specifying only safety, a process is not    *)
    34→--     (* required to receive a message, so there is no need to model message *)
    35→--     (* loss.  (There's no difference between a process not being able to   *)
    36→--     (* receive a message because the message was lost and a process simply *)
    37→--     (* ignoring the message.)  We therefore represent message passing with *)
    38→--     (* a variable $msgs$ whose value is the set of all messages that have  *)
    39→--     (* been sent.  Messages are never removed from $msgs$.  An action      *)
    40→--     (* that, in an implementation, would be enabled by the receipt of a    *)
    41→--     (* certain message is here enabled by the existence of that message in *)
    42→--     (* $msgs$.  (Receipt of the same message twice is therefore allowed;   *)
    43→--     (* but in this particular protocol, receiving a message for the second *)
    44→--     (* time has no effect.)                                                *)
    45→--     (***********************************************************************)
    46→
    47→-- Message ==
    48→--   (*************************************************************************)
    49→--   (* The set of all possible messages.  Messages of type $"Prepared"$ are  *)
    50→--   (* sent from the RM indicated by the message's $rm$ field to the TM\@.   *)

    50→--   (* sent from the RM indicated by the message's $rm$ field to the TM\@.   *)
    51→--   (* Messages of type $"Commit"$ and $"Abort"$ are broadcast by the TM, to *)
    52→--   (* be received by all RMs.  The set $msgs$ contains just a single copy   *)
    53→--   (* of such a message.                                                    *)
    54→--   (*************************************************************************)
    55→--   [type : {"Prepared"}, rm : RM]  \cup  [type : {"Commit", "Abort"}]
    56→
    57→enum RMStateType = { working, prepared, committed, aborted }
    58→enum TMStateType = { init, tmCommitted, tmAborted }
    59→
    60→function rmState (r : RM) : RMStateType
    61→individual tmState : TMStateType
    62→relation tmPrepared (r : RM) : Bool
    63→
    64→relation msgPrepared (r : RM) : Bool
    65→individual msgCommit : Bool
    66→individual msgAbort : Bool
    67→
    68→#gen_state
    69→
    70→-- TPTypeOK ==
    71→--   (*************************************************************************)
    72→--   (* The type-correctness invariant                                        *)
    73→--   (*************************************************************************)
    74→--   /\ rmState \in [RM -> {"working", "prepared", "committed", "aborted"}]
    75→--   /\ tmState \in {"init", "committed", "aborted"}
    76→--   /\ tmPrepared \subseteq RM
    77→--   /\ msgs \subseteq Message
    78→
    79→-- TPInit ==
    80→--   (*************************************************************************)
    81→--   (* The initial predicate.                                                *)
    82→--   (*************************************************************************)
    83→--   /\ rmState = [rm \in RM |-> "working"]
    84→--   /\ tmState = "init"
    85→--   /\ tmPrepared   = {}
    86→--   /\ msgs = {}
    87→
    88→after_init {
    89→  rmState R := working
    90→  tmState := init
    91→  tmPrepared R := false
    92→  msgPrepared R := false
    93→  msgCommit := false
    94→  msgAbort := false
    95→}
    96→
    97→-- -----------------------------------------------------------------------------
    98→-- (***************************************************************************)
    99→-- (* We now define the actions that may be performed by the processes, first *)

The file /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean has been updated successfully.

/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:57:0: error: ❌ Violation: safety_failure (violates: values_valid)

The file /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean has been updated successfully.

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Examples/Puzzles/RiverCrossing.lean:6:individual wolf_pos : position
Examples/Puzzles/RiverCrossing.lean:7:individual goat_pos : position
Examples/Puzzles/RiverCrossing.lean:8:individual cabbage_pos : position
Examples/Puzzles/RiverCrossing.lean:9:individual farmer_pos : position
Examples/Puzzles/Prisoners.lean:12:individual switchAUp : Bool
Examples/Puzzles/Prisoners.lean:13:individual switchBUp : Bool
Examples/Puzzles/Prisoners.lean:15:individual count : Nat
Examples/Puzzles/DieHard.lean:6:individual big : Nat
Examples/Puzzles/DieHard.lean:7:individual small : Nat
Examples/Ivy/NOPaxos.lean:27:individual s_seq_msg_num : seq_t

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Examples/TLA/EWD840.lean:26:assumption [zero_one] next seq.zero one
Examples/TLA/EWD840.lean:27:assumption [max_seq_prop] ∀n, seq.le n max_node
Examples/TLA/MultiPaxos.lean:103:assumption [zero_one] next tot.zero one
Examples/TLA/MultiPaxos.lean:107:assumption [quorum_intersection]
Examples/TLA/Paxos.lean:30:-- (* The following lemma is an immediate consequence of the assumption.      *)
Examples/TLA/Paxos.lean:108:assumption [quorum_intersection]
Examples/TLA/Bakery.lean:36:assumption [zero_one_th] next_thread thread.zero one_th
Examples/TLA/Bakery.lean:37:assumption [one_index_th] ∀i, thread.le thread.zero i
Examples/TLA/Bakery.lean:38:assumption [nat_gt_zero] ∀n, seq.le seq.zero n
Examples/TLA/Bakery.lean:39:assumption [zero_one] next seq.zero one

[Showing results with pagination = limit: 10, offset: 0]

Examples/Ivy/PaxosEPR.lean:14:instantiate tot : TotalOrder round
Examples/Ivy/Ring.lean:6:instantiate tot : TotalOrder node
Examples/Ivy/Ring.lean:9:open Between TotalOrder
Examples/Tutorial/RingDec.lean:6:instantiate tot : TotalOrder node
Examples/Tutorial/RingDec.lean:9:open Between TotalOrder
Examples/Ivy/SuzukiKasami.lean:12:instantiate seq : TotalOrderWithMinimum seq_t
Examples/Ivy/NOPaxos.lean:15:instantiate seq : TotalOrderWithZero seq_t
Examples/Ivy/Blockchain.lean:11:instantiate tot : TotalOrder time
Examples/Synchronous/FasterFloodSet.lean:46:instantiate val_ord : TotalOrder value
Examples/Synchronous/FasterFloodSet.lean:47:open TotalOrder

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     1→import Veil
     2→
     3→veil module Ring
     4→
     5→type node
     6→instantiate tot : TotalOrder node
     7→instantiate btwn : Between node
     8→
     9→open Between TotalOrder
    10→
    11→relation leader : node → Bool
    12→relation pending : node → node → Bool
    13→
    14→#gen_state
    15→
    16→after_init {
    17→  leader N := false
    18→  pending M N := false
    19→}
    20→
    21→ghost relation isNext (n : node) (next : node) :=
    22→  ∀ Z, n ≠ next ∧ ((Z ≠ n ∧ Z ≠ next) → btw n next Z)
    23→
    24→action send (n next : node) {
    25→  require isNext n next
    26→  pending n next := true
    27→}
    28→
    29→action recv (sender n next : node) {
    30→  require isNext n next
    31→  require pending sender n
    32→  pending sender n := false
    33→  if (sender = n) then
    34→    leader n := true
    35→  else
    36→    if (le n sender) then
    37→      pending sender next := true
    38→}
    39→
    40→safety [single_leader] leader N ∧ leader M → N = M
    41→invariant [leader_greatest] leader L → le N L
    42→invariant [self_msg_greatest] pending L L → le N L
    43→invariant [drop_smaller] pending S D ∧ btw S N D → le N S
    44→
    45→#time #gen_spec
    46→
    47→#model_check { node := Fin 9 } { }
    48→
    49→sat trace {
    50→  any 3 actions
    51→  assert (∃ l, leader l)
    52→}
    53→
    54→unsat trace {
    55→  any 5 actions
    56→  assert (∃ n₁ n₂, n₁ ≠ n₂ ∧ leader n₁ ∧ leader n₂)
    57→}
    58→
    59→#check_invariants
    60→
    61→end Ring
    62→

The file /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean has been updated successfully.

/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:31:0: error: Error in action initializer: Type mismatch
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:60:0: error: [Module.declarationSplitParams]: procedure initializer not found
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:63:0: error: The specification of module MaxCounter has not been finalized. Please call #gen_spec first!
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:66:0: error: The specification of module MaxCounter has not been finalized. Please call #gen_spec first!

    30→-- Init ==
    31→--   /\ active \in [Node -> BOOLEAN]
    32→--   /\ color \in [Node -> Color]
    33→--   /\ tpos \in Node
    34→--   /\ tcolor = "black"
    35→/- Has the same num of states as TLA+ version. -/
    36→after_init {
    37→  let S1 ← pick nodesSet
    38→  let S2 ← pick nodesSet
    39→  active N := if nSet.contains N S1 then true else false
    40→  colormap N := if nSet.contains N S2 then white else black
    41→  tpos := *
    42→  tcolor := black
    43→}
    44→
    45→
    46→-- InitiateProbe ==
    47→--   /\ tpos = 0
    48→--   /\ tcolor = "black" \/ color[0] = "black"
    49→--   /\ tpos' = N-1

Examples/Puzzles/Prisoners.lean:28:  switchAUp := *
Examples/Puzzles/Prisoners.lean:29:  switchBUp := *
Examples/TLA/EWD840.lean:41:  tpos := *
Examples/Synchronous/FasterFloodSet.lean:88:  initialValue := *
Examples/Ivy/Blockchain.lean:67:  block_confirmed N B t := *
Examples/Ivy/Blockchain.lean:81:    transaction_confirmed TR n := *
Examples/Synchronous/FloodSet.lean:74:  initialValue := *

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VeilTest/Regression/GhostRel.lean:9:instantiate LClock : TotalOrderWithZero LClockType
VeilTest/Regression/GhostRel.lean:15:instantiate MEM_C_LClock : TotalOrderWithZero MEM_C_LClockType
VeilTest/ComplexSyntax.lean:17:instantiate seq : TotalOrderWithMinimum seq_t
Veil/Frontend/Std.lean:97:class TotalOrderWithZero (t : Type) where
Veil/Frontend/Std.lean:112:instance total_order_with_zero_fin (n : Nat) [nz : NeZero n] : TotalOrderWithZero (Fin n) where
Veil/Frontend/Std.lean:123:instance total_order_with_zero_fin_dec (n : Nat) [nz : NeZero n] : ∀ a b, Decidable (TotalOrderWithZero.le (t := Fin n) a b) := by
Veil/Frontend/Std.lean:124:  dsimp [TotalOrderWithZero.le]; apply inferInstance
Veil/Frontend/Std.lean:128:class TotalOrderWithMinimum (t : Type) where
Veil/Frontend/Std.lean:147:instance (n : Nat): TotalOrderWithMinimum (Fin n.succ) where
Veil/Frontend/Std.lean:154:  le_lt := by intros; dsimp [TotalOrderWithMinimum.lt, TotalOrderWithMinimum.le]; omega

[Showing results with pagination = limit: 10, offset: 0]

    97→class TotalOrderWithZero (t : Type) where
    98→  -- relation: total order
    99→  le (x y : t) : Prop
   100→  -- axioms
   101→  le_refl       (x : t) : le x x
   102→  le_trans  (x y z : t) : le x y → le y z → le x z
   103→  le_antisymm (x y : t) : le x y → le y x → x = y
   104→  le_total    (x y : t) : le x y ∨ le y x
   105→  -- zero
   106→  zero : t
   107→  zero_le (x : t) : le zero x
   108→
   109→/-! ### Instances -/
   110→
   111→/-- Non-empty finite types are total orders with zero. -/
   112→instance total_order_with_zero_fin (n : Nat) [nz : NeZero n] : TotalOrderWithZero (Fin n) where
   113→  le := fun x y => x.val ≤ y.val
   114→  le_refl := by simp
   115→  le_trans := by simp ; omega
   116→  le_antisymm := by simp ; omega
   117→  le_total := by simp ; omega
   118→  zero := ⟨0, by cases nz; grind⟩
   119→  zero_le := by simp
   120→
   121→/-! ### Decidability -/
   122→
   123→instance total_order_with_zero_fin_dec (n : Nat) [nz : NeZero n] : ∀ a b, Decidable (TotalOrderWithZero.le (t := Fin n) a b) := by
   124→  dsimp [TotalOrderWithZero.le]; apply inferInstance
   125→
   126→/-! ## Total order with minimum -/
   127→
   128→class TotalOrderWithMinimum (t : Type) where
   129→  -- relation: strict total order
   130→  le (x y : t) : Prop
   131→  -- axioms
   132→  le_refl (x : t) : le x x
   133→  le_trans (x y z : t) : le x y → le y z → le x z
   134→  le_antisymm (x y : t) : le x y → le y x → x = y
   135→  le_total (x y : t) : le x y ∨ le y x
   136→  -- relation: nonstrict total order

The file /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean has been updated successfully.

/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:28:0: error: Error in action initializer: mvar(s) exist in the elaborated expression. Consider adding more type annotations.
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:54:0: error: [Module.declarationSplitParams]: procedure initializer not found
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:57:0: error: The specification of module MaxCounter has not been finalized. Please call #gen_spec first!
/Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean:60:0: error: The specification of module MaxCounter has not been finalized. Please call #gen_spec first!

Examples/TLA/MultiPaxos.lean:103:assumption [zero_one] next tot.zero one

[Showing results with pagination = limit: 10, offset: 0]

Examples/TLA/EWD840.lean:26:assumption [zero_one] next seq.zero one
Examples/TLA/EWD840.lean:54:  require tpos = seq.zero
Examples/TLA/EWD840.lean:55:  require tcolor = black ∨ colormap seq.zero = black
Examples/TLA/EWD840.lean:58:  colormap seq.zero := white
Examples/TLA/EWD840.lean:77:  require i ≠ seq.zero
Examples/TLA/EWD840.lean:114:  tpos = seq.zero ∧ tcolor = white ∧ colormap seq.zero = white ∧ ¬ active seq.zero
Examples/TLA/EWD840.lean:119:ghost relation P1 := ∃j, (seq.le seq.zero j) ∧ (seq.le j tpos) ∧ colormap j = black
Examples/TLA/EWD840.lean:122:∨ (∃j, (seq.le seq.zero j) ∧ (seq.le j tpos) ∧ colormap j = black)
Examples/TLA/MultiPaxos.lean:103:assumption [zero_one] next tot.zero one
Examples/TLA/Bakery.lean:36:assumption [zero_one_th] next_thread thread.zero one_th
Examples/TLA/Bakery.lean:37:assumption [one_index_th] ∀i, thread.le thread.zero i
Examples/TLA/Bakery.lean:38:assumption [nat_gt_zero] ∀n, seq.le seq.zero n
Examples/TLA/Bakery.lean:39:assumption [zero_one] next seq.zero one
Examples/TLA/Bakery.lean:45: ghost relation num_gt_zero (i : process) := lt seq.zero (num i)
Examples/TLA/Bakery.lean:89:  num P := seq.zero

[Showing results with pagination = limit: 15, offset: 0]

The file /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean has been updated successfully.

✅ No violation (explored 64 states)
✅ Satisfying trace found

     1→import Veil
     2→
     3→/-!
     4→  # Max Counter
     5→
     6→  A distributed system where multiple servers each maintain a counter.
     7→  Clients can read or update any server's counter, but updates only take
     8→  effect if the new value is strictly greater than the current one.
     9→  Servers periodically synchronize pairwise, propagating the maximum
    10→  value. Eventually, in the absence of further client writes, all servers
    11→  converge to the same (maximum) counter value.
    12→-/
    13→
    14→veil module MaxCounter
    15→
    16→type server
    17→type value
    18→instantiate tot : TotalOrderWithZero value
    19→
    20→-- Each server maintains a counter value
    21→function counter : server → value
    22→
    23→#gen_state
    24→
    25→-- All counters start at zero
    26→after_init {
    27→  counter S := tot.zero
    28→}
    29→
    30→-- A client sets a server's counter to a new value,
    31→-- but only if the new value is strictly greater than the current one.
    32→action clientSet (s : server) (v : value) {
    33→  require ¬ (tot.le v (counter s))
    34→  counter s := v
    35→}
    36→
    37→-- Two servers synchronize: the destination server adopts the
    38→-- source server's value if it is larger. This models periodic
    39→-- pairwise gossip synchronization.
    40→action serverSync (src dst : server) {
    41→  require src ≠ dst
    42→  if ¬ (tot.le (counter src) (counter dst)) then
    43→    counter dst := counter src
    44→}
    45→
    46→-- Safety: all counters are always at least zero (they can only increase)
    47→safety [counters_nonneg] ∀ (s : server), tot.le tot.zero (counter s)
    48→
    49→-- Invariant: same, for inductive verification
    50→invariant [counters_nonneg_inv] ∀ (s : server), tot.le tot.zero (counter s)
    51→
    52→#gen_spec
    53→
    54→-- Model check with small finite instantiation
    55→#model_check { server := Fin 3, value := Fin 4 }
    56→
    57→-- Verify that values can propagate via sync
    58→sat trace {
    59→  any 3 actions
    60→  assert (∃ s₁ s₂ : server, s₁ ≠ s₂ ∧ counter s₁ = counter s₂ ∧
    61→    ¬ (counter s₁ = tot.zero))
    62→}
    63→
    64→end MaxCounter
    65→

The file /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.lean has been updated successfully.

✅ No violation (explored 64 states)
✅ Satisfying trace found
✅ Satisfying trace found

File created successfully at: /Users/apanda/code/agent-spec/veil/Examples/apanda/MaxCounter.md

Perfect! Now I have a comprehensive understanding of the skill format. Let me compile my findings.

## Summary

I found the jujutsu skill files and other skill examples. Here's what I discovered about the skill format and metadata structure:

### Skill File Locations

1. **Jujutsu Skill (Main):**
   - `/Users/apanda/code/agent-spec/veil/.claude/skills/jujutsu.md`
   - `/Users/apanda/code/agent-spec/agent-spec-code/.claude/skills/jujutsu.md`

2. **Other Skill Files (for reference):**
   - `/Users/apanda/code/agent-spec/agent-spec-code/.claude/skills/gleam-otp.md`
   - `/Users/apanda/code/agent-spec/agent-spec-code/.claude/skills/create-emulation.md`

### Skill Format and Metadata Structure

Skills are **Markdown files** located in the `.claude/skills/` directory. The format includes:

**Metadata Section** (at the top of the file):
```markdown
## Metadata
name: <skill name>
description: <skill description>
```

**Content Sections:**
- Organized with headers (## for main sections, ### for subsections)
- Use markdown formatting (code blocks with language identifiers, bullet lists, etc.)
- Example-driven with code snippets
- Can reference other skills (e.g., the `create-emulation.md` skill references both `gleam-otp` and `jujutsu`)

**Jujutsu Skill Specifics:**
The jujutsu skill covers:
- Version information (0.35.0 as of March 2026)
- Key differences from Git (working copy snapshots, change IDs, no staging area)
- Common commands (status, history, commits, file operations, branches, history rewriting)
- Commit message format (with heredoc examples)
- Useful revsets
- Common workflows (gitignore handling, fixing commits)

### Configuration

Skills are stored in the `.claude/skills/` directory and are referenced by the `Skill` tool. The settings are managed in `.claude/settings.local.json` which can contain permissions and other configuration (like attribution and plans directory).

agentId: a87905134b982dda1 (for resuming to continue this agent's work if needed)
<usage>total_tokens: 22230
tool_uses: 15
duration_ms: 187911</usage>

     1→# Jujutsu (jj) Version Control
     2→
     3→**Version:** 0.35.0 (as of March 2026)
     4→
     5→> **Note:** Jujutsu is under active development. Commands and behavior may change between versions. Check `jj --version` and `jj <command> --help` if something doesn't work as expected.
     6→
     7→## Key Differences from Git
     8→
     9→- Working copy is automatically snapshotted on every command
    10→- No staging area - all changes are part of the working copy commit
    11→- Commits are identified by change IDs (stable) and commit IDs (change with rewrites)
    12→- The `@` symbol refers to the current working copy commit
    13→- `@-` refers to the parent of the working copy
    14→
    15→## Common Commands
    16→
    17→### Status and History
    18→
    19→```sh
    20→jj status              # Show working copy changes
    21→jj log                 # Show commit history
    22→jj log --limit 5       # Show last 5 commits
    23→jj diff                # Show changes in working copy
    24→jj diff -r @-          # Show changes in parent commit
    25→```
    26→
    27→### Creating Commits
    28→
    29→```sh
    30→jj commit -m "message"           # Commit working copy with message
    31→jj describe -m "message"         # Set/change description of current commit
    32→jj new                           # Create new empty commit on top of current
    33→jj new -m "message"              # Create new commit with message
    34→```
    35→
    36→### File Operations
    37→
    38→**IMPORTANT:** File operations use `jj file` subcommand, not top-level commands.
    39→
    40→```sh
    41→jj file list                     # List tracked files
    42→jj file track <path>             # Start tracking a file
    43→jj file untrack <path>           # Stop tracking a file (keeps file on disk)
    44→jj file untrack 'glob/**'        # Untrack files matching glob pattern
    45→```
    46→
    47→> **Gotcha:** There is no `jj untrack` - you must use `jj file untrack`.
    48→
    49→### Restoring and Reverting
    50→
    51→```sh
    52→jj restore <path>                # Restore file to parent commit state
    53→jj restore --from @- <path>      # Restore from specific revision
    54→```
    55→
    56→### Branches and Bookmarks
    57→
    58→```sh
    59→jj bookmark list                 # List bookmarks (jj's term for branches)
    60→jj bookmark create <name>        # Create bookmark at current commit
    61→jj bookmark set <name>           # Move bookmark to current commit
    62→```
    63→
    64→### Working with History
    65→
    66→```sh
    67→jj squash                        # Squash current commit into parent
    68→jj edit <revision>               # Edit an earlier commit
    69→jj rebase -d <destination>       # Rebase current commit onto destination
    70→```
    71→
    72→## Commit Message Format
    73→
    74→Use heredoc for multi-line messages:
    75→
    76→```sh
    77→jj commit -m "$(cat <<'EOF'
    78→Short summary line
    79→
    80→Longer description here.
    81→Can be multiple paragraphs.
    82→
    83→Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
    84→EOF
    85→)"
    86→```
    87→
    88→## Useful Revsets
    89→
    90→```sh
    91→jj log -r @              # Current commit only
    92→jj log -r @-             # Parent of current
    93→jj log -r @--            # Grandparent
    94→jj log -r "heads()"      # All head commits
    95→jj log -r "root()..@"    # All commits from root to current
    96→```
    97→
    98→## Common Workflows
    99→
   100→### Adding .gitignore After Build Artifacts Exist
   101→
   102→1. Create `.gitignore` with patterns
   103→2. Untrack the files that should be ignored:
   104→   ```sh
   105→   jj file untrack 'build/**'
   106→   ```
   107→3. Commit the changes
   108→
   109→### Fixing the Last Commit
   110→
   111→```sh
   112→# Make changes to files, then:
   113→jj squash                # Squash changes into parent
   114→# Or to change the message:
   115→jj describe -m "new message"
   116→```
   117→
   118→## Tips
   119→
   120→- Use `--no-pager` flag to disable paging for scripted output
   121→- Use `-r` or `--revision` to specify which commit to operate on
   122→- Check `jj <command> --help` for detailed options
   123→- The working copy is always snapshotted automatically - no need to manually add files
   124→

jujutsu.md

/Users/apanda/code/agent-spec/veil/.claude/settings.local.json

     1→{
     2→  "attribution": {
     3→    "commit": "🤖 Generated with Claude Code"
     4→  },
     5→  "permissions": {
     6→    "allow": [
     7→      "Bash(ls:*)",
     8→      "Bash(wc:*)",
     9→      "Bash(lake lean:*)"
    10→    ]
    11→  },
    12→  "plansDirectory": "./claude-plans"
    13→}
    14→

File created successfully at: /Users/apanda/code/agent-spec/veil/.claude/skills/veil.md