feat(task): add the pure run-state kernel module (RSK-01)

[edelauna]

Related GitHub Issue

Closes: #1791

Description

This PR adds the pure run-state kernel module (RSK-01 of the run-state kernel epic, #1790). The module is dead code. No production file imports it.

• src/core/task/run-state/runState.ts: defines Phase, Stream, Ask, Latches, RunState, RunEvent, AbortReason, and Transition from docs/architecture/task-lifecycle-target-architecture.md. AbortReason is ClineApiReqCancelReason.
• nextRunState(state, event) follows the guard and effect table. It is pure. When a guard fails, it returns { rejected: state } with the state unchanged. A stale askSettled and a later reasonSet return { ok: state }, because the design doc defines them as no-ops, not rejections.
• The getters are abort, abandoned, abortReason, didFinishAbortingStream, isStreaming, and isInitialized.
• initialRunState is the start value for a new instance. It is frozen at every level, so a caller cannot change the start state of later instances.
• AGENTS.md: names the run-state submodel and its location under "Task Lifecycle Changes".
• runState.spec.ts: covers every event on its guard edge, every getter, observed flows 1 to 10, and races R-3, R-4, and R-6. Each accepted edge asserts the whole state, so an effect that writes an extra field fails a test.

Reviewers: the kernel does not check the stream region in completionAccepted. A task can complete while a stream is live. This matches the design doc, and the spec covers the state.

Test Procedure

1. From src, run pnpm exec vitest run core/task/run-state. 99 tests pass.
2. From src, run pnpm exec tsc --noEmit. No errors.
3. From src, run pnpm exec eslint --max-warnings=0 core/task/run-state. No errors.
4. Run grep -rn "run-state/runState" src webview-ui packages apps --include='*.ts' --include='*.tsx'. Only the spec file matches.

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Testing: New and/or updated tests have been added to cover my changes (if applicable).
• Visual Snapshot (UI changes only): Not applicable. This PR has no UI change.
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Documentation Updates

• No documentation updates are required.

Additional Notes

RSK-02 (#1792) extends the bounded model-check to this module. RSK-04 (#1794) adds the run field and the write helpers that first use it.

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🧠 Learnings (1)

📓 Common learnings

Learnt from: CR
Repo: Zoo-Code-Org/Zoo-Code

Timestamp: 2026-10-06T02:29:11.480Z
Learning: Source excerpt:
# AGENTS.md

## Test Placement Guidance

- Use package-local unit tests for pure logic, parsing, state transitions, validation, serialization, request construction, retry decisions, and error handling.

Learnt from: CR
Repo: Zoo-Code-Org/Zoo-Code

Timestamp: 2026-10-06T02:29:11.480Z
Learning: Source excerpt:
# AGENTS.md

## Task Lifecycle Changes

- The in-memory run-state submodel lives in `src/core/task/run-state/runState.ts`. It is a pure `nextRunState(state, event)` kernel, separate from the persisted reducers. Read `docs/architecture/task-lifecycle-target-architecture.md` before changing it.

Learnt from: CR
Repo: Zoo-Code-Org/Zoo-Code

Timestamp: 2026-10-06T02:29:11.480Z
Learning: Source excerpt:
# AGENTS.md

## Task Lifecycle Changes

- The in-memory run-state submodel lives in `src/core/task/run-state/runState.ts`. It is a pure `nextRunState(state, event)` kernel, separate from the persisted reducers. Read `docs/architecture/task-lifecycle-target-architecture.md` before changing it.

---

📝 Summary

Summary by CodeRabbit

• New Features
  • Task runs now maintain consistent status across initialization, streaming, aborts, retries, and completion. This helps keep outcomes accurate as a run moves through its lifecycle.
  • Run status preserves the first abort reason and tracks stream cleanup, including when events arrive late or repeat. This keeps reported run status consistent during and after interruptions.

Walkthrough

Adds a pure run-state kernel with typed lifecycle state, guarded event transitions, and selectors. Adds tests for transitions, getters, observed flows, and race cases. The module is not wired into production code.

Changes

Run-state kernel

Layer / File(s)	Summary
State model and transitions src/core/task/run-state/runState.ts, AGENTS.md	Adds the run-state types, immutable initial state, guarded nextRunState transitions, and selectors. AGENTS.md directs agents to read the target architecture before changing the kernel.
Transition and flow tests src/core/task/run-state/__tests__/runState.spec.ts	Adds coverage for event acceptance and rejection, getters, immutability, lifecycle sequences, retries, and late ask settlements.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Feature

Merge Risk: ⚪ Minimal · up to bc9bb

No issue identified here requires a change before merge; normal checks remain appropriate.

Security Architecture Review

Security architecture risk: ⚪ Minimal · up to a15e6

The new lifecycle contract is used only by tests and does not change production permissions, privileged operations, or deployment behavior. The reviewed transitions match the intended lifecycle rules, with no material security risk identified in this change.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The effective exposure of this PR is confined to the isolated module and its tests. Source inspection found no production caller connecting attacker-controlled input to these transitions or to a privileged downstream operation.

Trust Boundaries and Controls

• observed — Ask settlement and completion use askTs correlation. A stale settlement cannot clear a newer pending ask when their identifiers differ, and completion requires the recorded completion identifier. The module itself does not authenticate event producers or establish identifier uniqueness.

Resilience and Maintainability Implications

• inferred — Future integration must preserve serialized state ownership and generation-aware handling of detached work. The pure transition model alone cannot guarantee that a late external cleanup or write targets the correct operation; no production integration introduces that exposure in this PR.

🚥 Pre-merge checks | ✅ 8

✅ Passed checks (8 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	[#1791] The change adds the requested run-state types, lastCompletionAskTs, pure nextRunState transitions, and six getters. The reported implementation preserves state on rejected guards and treat…
Out of Scope Changes check	✅ Passed	The reported changes are limited to runState.ts, its tests, and the AGENTS.md guidance. Each supports an explicit [#1791] requirement. No unrelated change is identified.
Regression Evidence	✅ Passed	The PR adds the kernel and focused unit tests. The transition tests cover each event’s accepted effect and relevant rejected, no-op, and unset cases (runState.spec.ts:80–407). Getter tests cover initi…
Security Boundaries	✅ Passed	No changed path meets the security failure conditions. runState.ts adds a pure state-transition function and selectors; it does not read or emit secrets or PII, execute input, or perform approval de…
Persistence Integrity	✅ Passed	No changed persistence path exists. The PR adds the pure nextRunState value transition and getters; the implementation has no storage calls, awaited operations, or persistence writes. The reference …
Lifecycle Resource Cleanup	✅ Passed	No changed resource lifecycle path exists. The PR adds only the pure nextRunState kernel and guidance/tests; runState.ts updates immutable state and contains no listener, watcher, provider, timer,…
Title check	✅ Passed	The title clearly identifies the main change: adding the pure run-state kernel module.
Description check	✅ Passed	The description covers the linked issue, implementation, test procedure, checklist, documentation impact, and additional notes. The Self-Review and Contribution Guidelines checklist items remain unche…

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• 🪄 Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at @src/core/task/run-state/__tests__/runState.spec.ts:
- Around line 409-418: Add a focused test alongside the frozen-input tests in
runState.spec.ts that asserts initialRunState has the exact expected values and
that the state and its stream, ask, and latches objects are frozen. Keep the
existing mutation test unchanged.

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🧠 Learnings (1)

📓 Common learnings

Learnt from: CR
Repo: Zoo-Code-Org/Zoo-Code

Timestamp: 2026-10-06T01:57:31.879Z
Learning: Source excerpt:
# AGENTS.md

## Test Placement Guidance

- Use package-local unit tests for pure logic, parsing, state transitions, validation, serialization, request construction, retry decisions, and error handling.

Learnt from: CR
Repo: Zoo-Code-Org/Zoo-Code

Timestamp: 2026-10-06T01:57:31.879Z
Learning: Source excerpt:
# AGENTS.md

## Task Lifecycle Changes

- The in-memory run-state submodel lives in `src/core/task/run-state/runState.ts`. It is a pure `nextRunState(state, event)` kernel, separate from the persisted reducers. Read `docs/architecture/task-lifecycle-target-architecture.md` before changing it.

Learnt from: CR
Repo: Zoo-Code-Org/Zoo-Code

Timestamp: 2026-10-06T01:57:31.879Z
Learning: Source excerpt:
# AGENTS.md

## Task Lifecycle Changes

- The in-memory run-state submodel lives in `src/core/task/run-state/runState.ts`. It is a pure `nextRunState(state, event)` kernel, separate from the persisted reducers. Read `docs/architecture/task-lifecycle-target-architecture.md` before changing it.

🪛 GitHub Check: mutation-diff

src/core/task/run-state/runState.ts

[warning] 142-142: Mutation test advisory
src/core/task/run-state/runState.ts:142: Survived ArrowFunction mutant (replacement: () => undefined). See the job summary for the complete list and resolution guidance.

---

[warning] 102-102: Mutation test advisory
src/core/task/run-state/runState.ts:102: 2 mutation test gaps; example: Survived ConditionalExpression mutant (replacement: false). See the job summary for the complete list and resolution guidance.

---

[warning] 51-51: Mutation test advisory
src/core/task/run-state/runState.ts:51: 4 mutation test gaps; example: Survived ObjectLiteral mutant (replacement: {}). See the job summary for the complete list and resolution guidance.

---

[warning] 50-50: Mutation test advisory
src/core/task/run-state/runState.ts:50: 2 mutation test gaps; example: Survived ObjectLiteral mutant (replacement: {}). See the job summary for the complete list and resolution guidance.

---

[warning] 49-49: Mutation test advisory
src/core/task/run-state/runState.ts:49: 2 mutation test gaps; example: Survived ObjectLiteral mutant (replacement: {}). See the job summary for the complete list and resolution guidance.

---

[warning] 47-47: Mutation test advisory
src/core/task/run-state/runState.ts:47: Survived StringLiteral mutant (replacement: ""). See the job summary for the complete list and resolution guidance.

---

[warning] 46-46: Mutation test advisory
src/core/task/run-state/runState.ts:46: Survived ObjectLiteral mutant (replacement: {}). See the job summary for the complete list and resolution guidance.

🔇 Additional comments (2)

src/core/task/run-state/runState.ts (1)

54-153: LGTM!

AGENTS.md (1)

52-52: LGTM!