Module executor 

Durable graph executor — the node-visiting drive loop.

Ports the semantics of the greentic-designer spike (src/orchestrate/agent_graph/executor.rs, origin/spike/agent-graph-engine-slice) with the following adaptations:

• Uses GraphConfig / GraphRunState / CheckpointStore from this crate rather than the designer’s SQLite-backed checkpoint module.
• Effect closures are Arc<dyn Fn(…) -> BoxFut<…>> (shared, cloneable) instead of owned Box<dyn Fn…>.
• start/resume return Result<GraphRunOutcome, GraphExecError> (not Result<()>), carrying the final reply and visit trail.

Record-then-checkpoint ordering (replayable resume)

Each side-effect node (Agent, Tool) follows a strict two-write ordering: the effect’s result is recorded into the node-visit store (CheckpointStore::record_node_visit) immediately after the effect returns and before the checkpoint update. The checkpoint update then commits the new cursor, state, and per-node visits counts atomically.

On resume at cursor node N, the next attempt is visits[N] + 1. If a (run, N, attempt) visit row already exists, the effect ran but the process crashed before the checkpoint committed — so the recorded result is replayed instead of re-invoking the effect.

Structs

AgentTurnRequest

Request payload delivered to an injected agent-turn closure.

AgentTurnResult

Result returned by an injected agent-turn closure.

ApprovalRequest

Request payload delivered to an injected approval closure.

GraphExecutor

Drives agent-graph runs to completion, persisting checkpoints after every node so that a killed process can resume mid-loop.

GraphRunOutcome

The final result of a drive-loop execution.

SupervisorRequest

Request payload delivered to an injected supervisor closure.

SupervisorResult

Result returned by an injected supervisor closure.

ToolCallRequest

Request payload delivered to an injected tool closure.

Enums

ApprovalOutcome

Result returned by an injected approval closure.

GraphExecError

Errors that may surface from GraphExecutor::start or GraphExecutor::resume.

Constants

MAX_NODE_VISITS

Hard upper bound on node visits per drive call, independent of the per-router maxIterations cap. Prevents infinite loops on malformed graphs.

Type Aliases

AgentTurnFn

One agent turn: the host wires this to AgentRuntime::step.

ApprovalFn

One approval-gate check: the host wires this to its approval-request transport (e.g. the greentic.approval.request.v1 / .response.v1 NATS subjects) and reports whether a decision has arrived yet.

BoxFut

Owned heap-allocated future, Send + 'static.

SupervisorFn

One supervisor routing decision: the host wires this to AgentRuntime::step with a generated routing prompt containing the route menu.

ToolFn

One deterministic tool call.