I4000 — A repeated executions.start with the same key answers one execution

○READY wave 0 · p1 · implementation profile · parallel safe

Part of a-session-proceeds-through-the-mesh — A session proceeds through the mesh: it finds the work, claims it once, runs it watched and stops when the intent is met.

Objective

Give executions.start an optional idempotency key; ExecutionStore::create returns the existing execution id for a key it has already seen instead of creating a second execution (Mission Control B1).

Why

A double click or a retried client starts two executions of the same capability today; nothing in ExecutionStore::create recognises a repeat.

Current state

Not built: this issue is planned by the milestone a-session-proceeds-through-the-mesh and nothing of it exists.

Desired state

The acceptance criteria below hold and case 4000 proves them.

Scope

• apps/majordomus-cli/src/execution/store.rs
• apps/majordomus-cli/src/capability/builtin/executions.rs
• docs/EXECUTIONS.md
• test/cases/4000_executions_start_takes_an_idempotency_key.sh
• .ai/repo/project/issues/I4000.yaml

Dependencies

None. This issue is a root of the graph.

What waits on this

• I4001✕BLOCKED The execution state machine has Authorizing, Claimed, Verifying, Refused and UnknownOutcome
• I4003✕BLOCKED Devtask.implement runs readiness, preflight, claim, worktree and one execution
• I4004✕BLOCKED The executor takes the issue's mesh claim in the handler and releases it when the run ends

Acceptance criteria

• A repeated executions.start with the same key answers the same execution id and starts no second execution
• A different key, or no key, behaves as before
• The key lives in the execution's own record: no new store

Validation

• env -u MAJORDOMUS_SHARE -u MAJORDOMUS_HTTP_HOST -u MJ_ROOT bash test/run.sh 4000_executions_start_takes_an_idempotency_key

Evidence required

• case_4000_executions_start_takes_an_idempotency_key

Evidence

None recorded. Every token above needs a command or an artifact behind it before this issue can be completed; narrative is refused.

Timeline

started

—

verified

—

completed

—

Those three fields, the evidence above and the state of the dependencies are all the status is made of. There is no status field to disagree with them.

Canonical record: .ai/repo/project/issues/I4000.yaml. Read it back with majordomus plan show I4000.