refactor: extract CooldownBeltComputer from CooldownSession (Wave 1B, #375)

[cmbays]

Summary

• Extract belt computation and agent confidence tracking into CooldownBeltComputer (85L)
• CooldownSession delegates via this.beltComputer.compute() and this.beltComputer.computeAgentConfidence()
• Per-agent error isolation: one failing agent no longer poisons the batch
• CooldownSession: 1,225 → 1,201 lines (-24)

Quality

Metric	Result
BDD scenarios	10 pass
Unit tests	17 pass (+ 3,416 existing)
Acceptance tests	66 pass
TypeScript	Clean
ArchUnit	14 of 15 (pre-existing CycleManager LCOM4)
Mutation score	82% total, 100% covered

Review Findings Addressed

• Per-agent error isolation (silent failure hunter, MEDIUM): moved try-catch inside the agent loop so one bad agent doesn't skip the rest
• Type design (type analyzer): grouped sub-objects deferred to Wave 3A
• Registry injection (silent failure hunter): deferred to Wave 3A DI cleanup
• Code review: clean, no issues above threshold

Deferred to Wave 3A

• Group co-dependent deps into sub-objects (belt?: { calculator, projectStateFile })
• @deprecated tags on kataka legacy fields
• Injectable KataAgentRegistry

Closes #375 partially (Wave 1B of 6)

🤖 Generated with Claude Code

Summary by CodeRabbit

Release Notes

• New Features

  • Belt level recomputation after cooldown with advancement logging and configuration control
  • Per-agent confidence computation including legacy practitioner alias support
  • Robust error handling for belt and confidence computation failures (logged as warnings without interrupting cooldown)

• Tests

  • Added acceptance criteria and unit test coverage for belt and confidence computation

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 3453083e-9d80-4d23-b7f3-8dd46ede178d

📥 Commits

Reviewing files that changed from the base of the PR and between c3429f0 and 8d953ce.

📒 Files selected for processing (7)

• src/acceptance/setup.ts
• src/features/cycle-management/cooldown-belt-computer.feature
• src/features/cycle-management/cooldown-belt-computer.steps.ts
• src/features/cycle-management/cooldown-belt-computer.test.ts
• src/features/cycle-management/cooldown-belt-computer.ts
• src/features/cycle-management/cooldown-session.ts
• stryker.config.mjs

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📝 Walkthrough

Walkthrough

Extracts belt computation and agent-confidence tracking logic from CooldownSession into a new CooldownBeltComputer collaborator class. Introduces implementation, unit tests, acceptance tests, and configuration updates to include the new module in mutation testing scope.

Changes

Cohort / File(s)	Summary
CooldownBeltComputer Core Implementation src/features/cycle-management/cooldown-belt-computer.ts	New module exporting CooldownBeltComputer class and CooldownBeltDeps interface. Implements compute() (loads project state, runs belt calculator, logs advancement, returns result or undefined on failure) and computeAgentConfidence() (resolves calculator/directory with fallbacks, iterates registered agents, catches and logs per-agent exceptions).
Acceptance Tests src/features/cycle-management/cooldown-belt-computer.feature, src/features/cycle-management/cooldown-belt-computer.steps.ts	New Gherkin feature file specifying belt evaluation (feature flag gating, missing state handling, advancement vs. steady behavior, error handling) and agent confidence tracking (per-agent computation, registry resolution, failure handling). Step definitions with world setup, spies, and assertions for belt results, advancement logging, calculator invocations, and warning messages.
Unit Tests src/features/cycle-management/cooldown-belt-computer.test.ts	Comprehensive unit tests for compute() (dependency gating, argument passing, advancement logging, error handling) and computeAgentConfidence() (per-agent iteration, calculator precedence, fallback behavior, missing input no-ops, exception continuation, registry loading failures).
Integration src/features/cycle-management/cooldown-session.ts	Removed inline belt/confidence computation methods; added beltComputer: CooldownBeltComputer collaborator initialized in constructor; delegated compute() and computeAgentConfidence() calls to collaborator in run() and complete().
Configuration src/acceptance/setup.ts, stryker.config.mjs	Added side-effect import for cooldown-belt-computer acceptance steps; added new module to Stryker mutation testing scope.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• PR #396 — Applies identical extraction pattern to CooldownSession, moving cycle/bridge-run syncing logic into a new BridgeRunSyncer collaborator class
• PR #387 — Adds unit tests exercising CooldownSession cooldown-related flows, overlapping with the refactored belt-computation behavior
• PR #378 — Adds acceptance setup import for session-bridge steps in src/acceptance/setup.ts, following the same side-effect import pattern

Poem

🐰 Belt logic hops away free,
A tidy new class, small and clean,
Agent confidence tracked in between,
Tests woven tight as can be!
Refactoring done with glee! 🎉

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 21.43% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'refactor: extract CooldownBeltComputer from CooldownSession (Wave 1B, #375)' accurately summarizes the main change: extracting belt computation logic into a new class and reducing CooldownSession complexity.
Linked Issues check	✅ Passed	The PR successfully addresses objectives from #375 Wave 1B by extracting CooldownBeltComputer to isolate belt/confidence computation, improving mutation-testing signal through reduced class complexity and better per-agent error handling, with 10 BDD scenarios and 17 unit tests passing.
Out of Scope Changes check	✅ Passed	All changes are tightly scoped to extracting belt computation: new CooldownBeltComputer class, updated CooldownSession delegation, supporting tests/features, and Stryker config updates. No unrelated refactoring or scope creep detected.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch worktree-kind-baking-pelican

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