/implement-feature

Implement Feature

Implement an approved feature plan with fresh-context slices, TDD, evidence, and PR-ready output.

**Input:** $ARGUMENTS

Optional args: slug=<feature>, ticket=<id/url>, mode=interactive|autonomous|channel, channel=<id>, auto_continue=true|false, profile=business|hybrid|technical.

Instructions

Execute the following steps for **$ARGUMENTS**.

Implement Feature Workflow

Goal: Build an approved feature through TDD slices and route completed work to verification.

Steps

1. Load plan:

• Search `docs/prd/` and `docs/srs/` for a matching `[slug]`; if absent, use the newest matching artifact.
• If multiple candidates exist, ask the user to choose or input the target slug.
• PRD or ticket
• SRS/FRS technical design if present
• Implementation plan
• Matched framework and common skills
• If stable `REQ-*`, `AC-*`, trace, or required SRS/test lanes are missing, stop and route to `plan-feature`, `design-solution`, or `implementation-readiness`.
• `snc_tier`/`model_tier` from handoff (score per `common-task-complexity-routing` if absent); `high` adds `specialist-architecture-guard` and `specialist-security-reviewer` before `verify-work`.

2. Prepare workspace:

• Confirm clean or intentionally dirty git state.
• Create branch or worktree only when project workflow expects it.
• Provision dependencies BEFORE tests (`npm ci`/`pnpm i`/`yarn`, `flutter pub get`, `./gradlew dependencies`, or `pip install -e .` from the lockfile); isolated worktrees lack ignored toolchains.
• If install fails from network, auth, or time budget, report `verification_infra_failed` with the exact command/error; never claim tests passed or silently skip verification.
• Initialize or update `docs/srs/srs-task-list.md` with small vertical slices.

3. Implement slices:

• For each slice, write or update the failing test first.
• Before the test, record its observable contract, distinct fault, smallest layer, minimal cases, and exact focused command (the Test Intent Record).
• Consume the named `REQ-*` and `AC-*` for each slice; do not invent scope from code inspection.
• For new behavior, do not keep pre-test implementation code as a reference: observe the expected RED first.
• For legacy or bug-fix slices, characterize only when needed, then make the intended change RED while preserving unrelated existing code.
• Implement the smallest passing code.
• Refactor without expanding scope.
• Run the focused target in foreground, single-run, sequential mode; classify invalid RED, unexpected GREEN, timeout, and cleanup instead of retrying blindly.
• Keep slice evidence near the task item.
• Use sub-agents only when the runtime supports them and ownership is disjoint.
• If a fix path is unclear, stop and apply root-cause debugging before more code changes.

4. Maintain context hygiene:

• Start fresh context for large independent slices when possible.
• Preserve decisions in `docs/srs/srs-task-list.md` or `docs/prd/prd-plan-[slug].md`.
• If behavior or scope changes, update `docs/prd/prd-[slug].md` and `docs/srs/srs-[slug].md` before closing the slice.
• Avoid carrying raw logs; summarize failures and fixes.

5. Prepare handoff:

• Run fresh local automated checks before claiming success.
• Update requirement trace notes for changed AC coverage.
• Capture evidence in `docs/srs/srs-walkthrough.md`.
• For autonomous/channel mode, delegate only with disjoint files, owner, AC IDs, expected artifact, and verification command.
• Route next step to `verify-work`.

Runtime Contract

• Use for approved plans ready to build; failing test first, no pre-test implementation kept as reference.
• Required inputs: PRD/ticket with stable `REQ-*`/`AC-*` trace and required SRS/test lanes.
• Return BLOCKED only when required trace, owner, or test lanes are missing.

Handoff Payload

• `slug`, `operator_profile` (carried, not re-inferred), `snc_tier`, `model_tier`, completed slices, tests run, changed contracts, delegation packets, outcome report, next workflow.

Blocking Questions

• Ask max 3 at a time with a recommended default and 2-3 options.

Output Template

# Implementation Handoff: [Name]
## Completed Slices
## Tests Run
## Changed Contracts
## Requirement Trace Updates
## Evidence
## Known Risks
## Delegation Packets
## Outcome Report
feature_status: partially_implemented | implemented | blocked
requirement_trace: BRD-OBJ-* -> REQ-* -> AC-* -> SRS-* -> evidence
completed_evidence: []; missing_evidence: []; decision_needed: []; recommended_next_workflow: verify-work | plan-feature | design-solution
## Next Workflow
verify-work
## Cost Report
Call `get_session_cost(workflow="implement-feature")` before final handoff.