A message reaches the running turn at once, and a stop ends the harness turn

spec:cc-agents.steering-and-stop

Use Case / Behavior · featureready floor ready

Packs: none

Design: no design entries · no pinned declarations · no decisions

specs/runner/steering-and-stop.sdp.md

No open questions and no blocking questions; implementation binding present, verifier binding present, and expected-outcome oracle none.

Intent

actor: A user or lead agent steering or stopping a foreign agent.
problem: Claude Code delivers a message to a subagent at a step boundary, and a stop aborts the step whose own calls are aborted with it, so neither would reach the harness reliably.
outcome: A message goes to the harness turn as it arrives, and a stop, from any route, ends the harness turn and gives its capacity back.
value: Steering a foreign agent feels like steering a Claude one, and a stopped agent leaves nothing running in a group the guard recorded.

Behavior

rule.steerNow line 27 · specs/runner/steering-and-stop.sdp.md:27: A message sent to a running agent of this plugin, by id or by name, is passed to its harness turn at once, and a message to any other recipient is delivered by Claude Code.
no example exercises it
rule.typedMessage line 28 · specs/runner/steering-and-stop.sdp.md:28: A message typed into the agent's own view is passed to the running turn at the next step, and one the ended turn cannot take waits for a new turn.
no example exercises it
rule.earlySteerWaits line 29 · specs/runner/steering-and-stop.sdp.md:29: A message that arrives before the harness has taken the turn is held by the sidecar and sent right after the turn starts, and once the turn has ended there is nothing to steer.
no example exercises it
rule.stopEndsTurn line 30 · specs/runner/steering-and-stop.sdp.md:30: A stop of the agent ends the harness turn too: the mod asks the sidecar to interrupt it from the turn-complete hook, because the aborted step cannot do it reliably.
no example exercises it
rule.leaseNet line 31 · specs/runner/steering-and-stop.sdp.md:31: A turn whose events nobody has read within the lease, 90 seconds by default, is interrupted by the sidecar.
no example exercises it
rule.noProcessLeftBehind line 32 · specs/runner/steering-and-stop.sdp.md:32: An interrupted turn leaves no process behind in the harness's group or in a group the guard recorded; the limit of that guarantee is spec:cc-agents.work-containment#question.detachedBeforeScan.
no example exercises it
rule.stopBeforeFirstStep line 33 · specs/runner/steering-and-stop.sdp.md:33: An agent stopped before its first turn gives back the slot reserved for it.
no example exercises it

0 unkeyed rules.

Verification

Verifier bindings

test:cc-agents.mod-suite · the mod against a scripted sidecar · anchored · test anchor binding present · plugin/tests/mod.test.ts:4
test:cc-agents.sidecar-suite · the sidecar, the Codex adapter, the slots and the guard against a fake Codex app-server · anchored · test anchor binding present · tests/sidecar.test.mjs:4

Design view

Requirement drawing

Declared verifying examples: no declared verifying example.

Requirement drawing for spec:cc-agents.steering-and-stop

The diagram as text

spec:cc-agents.steering-and-stop: A message reaches the running turn at once, and a stop ends the harness turn · declared Spec
spec:cc-agents.runner: Other model families run as real Claude Code agents · declared Spec
impl:cc-agents.mod: answers each step of an agent from the sidecar's events, hands back the exact answer, steers and stops, and returns the job state block · anchored code · plugin/hooks/register.js:9
impl:cc-agents.sidecar: the per-session sidecar: owns each harness turn, its events and its slot, and drives every adapter through the contract · anchored code · plugin/sidecar/server.mjs:12
test:cc-agents.mod-suite: the mod against a scripted sidecar · anchored test binding · binding present · plugin/tests/mod.test.ts:4
test:cc-agents.sidecar-suite: the sidecar, the Codex adapter, the slots and the guard against a fake Codex app-server · anchored test binding · binding present · tests/sidecar.test.mjs:4
spec:cc-agents.steering-and-stop refines spec:cc-agents.runner · declared
impl:cc-agents.mod satisfies spec:cc-agents.steering-and-stop · anchored
impl:cc-agents.sidecar satisfies spec:cc-agents.steering-and-stop · anchored
test:cc-agents.mod-suite verifies spec:cc-agents.steering-and-stop · anchored
test:cc-agents.sidecar-suite verifies spec:cc-agents.steering-and-stop · anchored

Mermaid source

Copyable source; the Studio draws static SVG.

Preferred and chosen syntax: requirementDiagram; exact refines, satisfies and verifies, with claim words in nodes and per-edge comments.

Mermaid source for Requirement drawing for spec:cc-agents.steering-and-stop

requirementDiagram
  requirement n0 {
    text: "A message reaches the running turn at once, and a stop ends the harness turn · declared Spec · spec:cc-agents.steering-and-stop"
  }
  element n1 {
    type: "answers each step of an agent from the sidecar's events, hands back the exact answer, steers and stops, and returns the job state block · anchored code · impl:cc-agents.mod"
  }
  element n2 {
    type: "the per-session sidecar: owns each harness turn, its events and its slot, and drives every adapter through the contract · anchored code · impl:cc-agents.sidecar"
  }
  element n3 {
    type: "the mod against a scripted sidecar · anchored test binding · binding present · test:cc-agents.mod-suite"
  }
  element n4 {
    type: "the sidecar, the Codex adapter, the slots and the guard against a fake Codex app-server · anchored test binding · binding present · test:cc-agents.sidecar-suite"
  }
  requirement n5 {
    text: "Other model families run as real Claude Code agents · declared Spec · spec:cc-agents.runner"
  }
  %% claim: anchored
  n1 - satisfies -> n0
  %% claim: anchored
  n2 - satisfies -> n0
  %% claim: declared
  n0 - refines -> n5
  %% claim: anchored
  n3 - verifies -> n0
  %% claim: anchored
  n4 - verifies -> n0

Decisions

No decision record named.

Runtime

impl:cc-agents.mod · answers each step of an agent from the sidecar's events, hands back the exact answer, steers and stops, and returns the job state block · plugin/hooks/register.js:9
Uses
None.
impl:cc-agents.sidecar · the per-session sidecar: owns each harness turn, its events and its slot, and drives every adapter through the contract · plugin/sidecar/server.mjs:12
Uses
None.

Runtime observation: not tracked.

Evidence

Runtime observation: not tracked.

Build attestations: not tracked.

Deployments: not tracked.

Bills of materials: not tracked.

Impact

Relations of spec:cc-agents.steering-and-stop

The diagram as text

spec:cc-agents.mod-layer: The mod answers an agent's steps from the sidecar and never calls a model
spec:cc-agents.runner: Other model families run as real Claude Code agents
spec:cc-agents.sidecar: One sidecar per Claude session owns the session's harness turns
spec:cc-agents.steering-and-stop: A message reaches the running turn at once, and a stop ends the harness turn
spec:cc-agents.work-containment: A guard ends the groups a harness turn started and it has seen, even when the sidecar is killed
spec:cc-agents.steering-and-stop dependsOn spec:cc-agents.mod-layer · declared — steering and stopping are hooks of the mod
spec:cc-agents.steering-and-stop dependsOn spec:cc-agents.sidecar · declared — the sidecar holds the running turn that a message reaches
spec:cc-agents.steering-and-stop dependsOn spec:cc-agents.work-containment · declared — what an interrupted turn leaves running is bounded by the groups the guard recorded
spec:cc-agents.steering-and-stop refines spec:cc-agents.runner · declared

Mermaid source

Copyable source; the Studio draws static SVG.

Preferred syntax: flowchart. Chosen syntax: labelled flowchart, preserving exact relations, claims and folds.

Mermaid source for Relations of spec:cc-agents.steering-and-stop

flowchart TB
  n0["Other model families run as real Claude Code agents · spec:cc-agents.runner"]
  n1["The mod answers an agent's steps from the sidecar and never calls a model · spec:cc-agents.mod-layer"]
  n2["One sidecar per Claude session owns the session's harness turns · spec:cc-agents.sidecar"]
  n3["A guard ends the groups a harness turn started and it has seen, even when the sidecar is killed · spec:cc-agents.work-containment"]
  n4["A message reaches the running turn at once, and a stop ends the harness turn · spec:cc-agents.steering-and-stop"]
  n4 -->|"dependsOn · declared — steering and stopping are hooks of the mod"| n1
  n4 -->|"refines · declared"| n0
  n4 -->|"dependsOn · declared — the sidecar holds the running turn that a message reaches"| n2
  n4 -->|"dependsOn · declared — what an interrupted turn leaves running is bounded by the groups the guard recorded"| n3

Rests on

refines · spec:cc-agents.runner · stated defined, floor ready
dependsOn · spec:cc-agents.mod-layer · stated ready, floor ready
dependsOn · spec:cc-agents.sidecar · stated ready, floor ready
dependsOn · spec:cc-agents.work-containment · stated ready, floor ready

Rested on by

No Spec rests on this Spec.

Relations

Relation and direction	Other end	Claim	Reason	Exercised keys
dependsOn · outgoing	The mod answers an agent's steps from the sidecar and never calls a model `spec:cc-agents.mod-layer` · resolves	declared	steering and stopping are hooks of the mod	None
dependsOn · outgoing	One sidecar per Claude session owns the session's harness turns `spec:cc-agents.sidecar` · resolves	declared	the sidecar holds the running turn that a message reaches	None
dependsOn · outgoing	A guard ends the groups a harness turn started and it has seen, even when the sidecar is killed `spec:cc-agents.work-containment` · resolves	declared	what an interrupted turn leaves running is bounded by the groups the guard recorded	None
refines · outgoing	Other model families run as real Claude Code agents `spec:cc-agents.runner` · resolves	declared	None	None

Bindings

Implementation binding: present

impl:cc-agents.mod · answers each step of an agent from the sidecar's events, hands back the exact answer, steers and stops, and returns the job state block · plugin/hooks/register.js:9
impl:cc-agents.sidecar · the per-session sidecar: owns each harness turn, its events and its slot, and drives every adapter through the contract · plugin/sidecar/server.mjs:12

Design reference: none

Verifier binding: present

test:cc-agents.mod-suite · the mod against a scripted sidecar · anchored · plugin/tests/mod.test.ts:4 · test anchor
test:cc-agents.sidecar-suite · the sidecar, the Codex adapter, the slots and the guard against a fake Codex app-server · anchored · tests/sidecar.test.mjs:4 · test anchor

Expected-outcome oracle: none

Runtime observation: not tracked.

Run results: not recorded in the graph.

Findings

None.

Composing (0)

Composing needs the script.