/feature

name: feature
description: 'TDD-first feature development — crystallise API as a demo test, drive implementation to pass it, run quality stack and a bounded independent challenge. TRIGGER when: user asks to build new functionality, add a capability, or implement a feature in a Python project; phrases: "add X", "implement Y", "build Z feature", "create a new module for". SKIP when: bug fixes (use `/develop:fix`); refactoring without new behaviour (use `/develop:refactor`); non-Python projects; `.claude/` config changes (use `/foundry:manage`).'
argument-hint: <goal> [--issue <N>] [--repo <owner/repo>] [--plan <path>] [--no-challenge] [--challenge] [--no-codemap] [--codemap] [--team] [--worktree] [--no-batch] [--accept-no-plan] [--keep "<items>"]
effort: xhigh
allowed-tools: Read, Write, Edit, Bash, Grep, Glob, Agent, Skill, TaskList, TaskCreate, TaskUpdate, AskUserQuestion, WebFetch, EnterWorktree, ExitWorktree
disable-model-invocation: true

<objective>

TDD-first feature development. Crystallise API as demo use-case test, drive implementation to pass it, close quality gaps with review, docs, quality stack.

NOT for:

• bug fixes (use `/develop:fix`)
• `.claude/` config changes (use `/foundry:manage` (requires foundry plugin))
• non-Python projects (JS/TS/Go/Rust) — toolchain assumes pytest, use language-native toolchain instead
• mixed refactor+feature tasks — run /develop:refactor first, then /develop:feature

</objective>

<compaction>

• Key boundary: end of Step 1 — scope analysis, plan complete, before Step 2 demo test writing.
• Second boundary: end of Step 3 — TDD loop complete, before Step 4 review/close gaps.
• Preserve at boundary 1: dev-dir (checkpoint.md), plan-file, scope from sw-engineer analysis, PYTEST_CMD, --keep items.
• Mid-loop refresh: after each Step 3 TDD cycle, contract rewritten with changed-files + checkpoint.md path — so mid-loop compaction resumes loop (re-run suite for green state) instead of restarting Step 2 demo.
• Preserve at boundary 2: dev-dir, changed files list, test outcomes, PYTEST_CMD.

</compaction>

<workflow>

<!-- Agent resolution: see _DEV_SHARED/agent-resolution.md (mounted by develop plugin init) -->

<!-- ../../assets/images/change-arch.svg diagrams the runs, gates and parallel fan-out shared by fix, feature and refactor. Documentation only, never loaded — update it in the same commit as any change to step order, gate placement, or agent fan-out. -->

Agent Resolution

export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
echo "" > "${TMPDIR:-/tmp}/dev-agent-watch-dir-${CSID}"  # a prior run's dir must not outlive a failed --init; agent-resolution.md §Agent waits recreates it when empty
python "${CLAUDE_PLUGIN_ROOT:-plugins/cc_develop}/bin/dev_shared_resolve.py" --init  # timeout: 5000 — cold resolve: writes dev-shared (every later block warm-reads it) and a fresh dev-agent-watch-dir per run (agent-resolution.md §Agent waits)
# loads: compaction-contract.md
python "${CLAUDE_PLUGIN_ROOT:-plugins/cc_develop}/bin/dev_load_shared.py" agent-resolution.md

Contains: foundry check + fallback table. If foundry not installed: substitute each `foundry:X` with `general-purpose` per table. Agents this skill uses: `foundry:sw-engineer`, `foundry:qa-specialist`, `foundry:doc-scribe`, `foundry:linting-expert`, `foundry:challenger`.

**Task hygiene** — task tools may be deferred; load before first use: `ToolSearch(query="select:TaskList,TaskCreate,TaskUpdate,TaskGet", max_results=4)`. Call `TaskList` first and triage each task it returns: `completed` if work clearly done, `deleted` if orphaned, keep `in_progress` only if genuinely continuing. Never spend a turn on bookkeeping alone — every `TaskCreate`/`TaskUpdate` ships in the same response as the next substantive tool call; one exception, `TaskUpdate(completed)` immediately before a long output block (`rules/task-lifecycle.md`).

Project Detection

export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
python "${CLAUDE_PLUGIN_ROOT:-plugins/cc_develop}/bin/dev_load_shared.py" runner-detection.md  # timeout: 5000

Sets `$TEST_CMD` (full suite) and `$PYTEST_CMD` (pytest flags). Run at skill start.

**Language preflight gate**: apply §Language preflight gate from `runner-detection.md` (loaded above) — sets `NON_PY` and runs the abort/continue question.

<!-- NON_PY and MULTI_LANG gates are mutually exclusive — NON_PY fires only when no Python markers exist; MULTI_LANG fires only when Python markers AND non-Python markers coexist. Both cannot be true on the same repo; never reorder so MULTI_LANG runs before NON_PY. -->

**Monorepo language-target gate**: if `NON_PY` empty (Python markers found) but non-Python markers also exist, confirm target language:

# timeout: 5000
MULTI_LANG=false
[ -f "pyproject.toml" ] && [ -f "package.json" ] && MULTI_LANG=true
[ -f "pyproject.toml" ] && [ -f "go.mod" ] && MULTI_LANG=true
[ -f "pyproject.toml" ] && [ -f "Cargo.toml" ] && MULTI_LANG=true

If `MULTI_LANG=true`: invoke `AskUserQuestion` — "Monorepo detected (Python + non-Python markers coexist). This skill targets Python/pytest. Is the feature you're building Python-only?" · (a) **Yes — Python only** — proceed · (b) **No — involves non-Python code too** — abort; use a language-native toolchain for the non-Python portion. On (b): stop.

**Optional `--plan <path>`**: `$ARGUMENTS` contains `--plan <path>` (at any position) → read plan file first. Extract `Affected files`, `Risks`, `Suggested approach` — use to populate Step 1 analysis instead of cold codebase exploration. Skip agent feasibility re-check (already done in `/develop:plan`). Store plan path as `PLAN_FILE`. The extraction block also records the plan's hash (`.plans/` is gitignored, so edits leave no diff); Final Report re-checks it.

export CSID="${CLAUDE_CODE_SESSION_ID:-$PPID}"
python "${CLAUDE_PLUGIN_ROOT:-plugins/cc_develop}/bin/dev_load_shared.py" preflight-helpers.md  # timeout: 5000

Execute --plan pa