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ln-401-task-executor
// Executes implementation tasks through Todo, In Progress, To Review. Use when task needs coding with KISS/YAGNI. Not for test tasks.
// Executes implementation tasks through Todo, In Progress, To Review. Use when task needs coding with KISS/YAGNI. Not for test tasks.
[HINT] Download the complete skill directory including SKILL.md and all related files
| name | ln-401-task-executor |
| description | Executes implementation tasks through Todo, In Progress, To Review. Use when task needs coding with KISS/YAGNI. Not for test tasks. |
| allowed-tools | Read, Grep, Glob, Bash, mcp__hex-line__outline, mcp__hex-line__read_file, mcp__hex-line__edit_file, mcp__hex-line__write_file, mcp__hex-line__verify, mcp__hex-line__changes, mcp__hex-line__inspect_path, mcp__hex-graph__index_project, mcp__hex-graph__find_symbols, mcp__hex-graph__inspect_symbol, mcp__hex-graph__analyze_edit_region |
| license | MIT |
Paths: File paths (
references/,../ln-*) are relative to this skill directory.
Type: L3 Worker
Executes a single implementation (or refactor) task from Todo to To Review using the task description and linked guides.
Hex MCP acceleration (if available): Use narrow inspect_path(path=<relevant dir>) and outline(file_path) before reading large code files; avoid repo-root wildcard inventories unless you intentionally need one. Use grep_search(output_mode="summary") first for search/discovery, then escalate to output_mode="content", edit_ready=true only when you need canonical hunks for follow-up edits; use allow_large_output=true only as an explicit last resort. Use read_file() in discovery mode for structure and targeted ranges; when you need revision and checksums for a follow-up edit, refresh that file with read_file(edit_ready=true, verbosity="full") before edit_file(). For edits to existing code, run index_project(path=project_root) once and use analyze_edit_region(...) before non-trivial edits. After edits: edit_file(base_revision=rev) -> verify(checksums). Before handoff: changes() to review diff.
| Input | Required | Source | Description |
|---|---|---|---|
taskId | Yes | args, parent Story, kanban, user | Task to execute |
Resolution: Task Resolution Chain. Status filter: Todo
MANDATORY READ: Load references/environment_state_contract.md, references/storage_mode_detection.md, references/tracker_provider_contract.md, references/provider_file.md, and references/input_resolution_pattern.md
Extract: task_provider = Task Management → Provider (linear | github | file). Operations stay provider-agnostic in this skill — see references/tracker_provider_contract.md for the canonical operation set and provider_*.md for transport binding.
Tool policy: follow host AGENTS.md MCP preferences; load references/mcp_tool_preferences.md and references/mcp_integration_patterns.md only when host policy is absent or MCP behavior is unclear. — use hex-line MCP for code files when available and hex-graph for semantic edit-risk questions.
Detect operating mode at startup:
Plan Mode Active:
Normal Mode:
When operating in any mode, skill MUST create detailed todo checklist tracking ALL steps.
Rules:
in_progress before starting step, completed after finishingTodo Template (10 items):
Step 1: Resolve taskId
- Resolve via args / Story context / kanban / AskUserQuestion (Todo filter)
Step 2: Load Context
- Fetch full task description + linked guides/manuals/ADRs
Step 2b: Goal Articulation Gate
- Complete 4 questions from references/goal_articulation_gate.md (<=25 tokens each)
Step 2c: Implementation Blueprint
- From task "Affected Components": extract file paths (Glob/Grep or narrow `inspect_path(path=<component dir>)` to find actual paths)
- Read each file (or key sections) to understand current structure
- IF modifying existing code in supported languages: `index_project(path=project_root)` once, then use path-scoped `find_symbols` / `inspect_symbol` for exact symbol identity and `analyze_edit_region` before editing non-trivial ranges
- IF `find_symbols` returns `partial ... truncated=1` or a broad candidate set: refine to `name + file` or `workspace_qualified_name` before planning from it
- Output:
## Implementation Blueprint: {taskId}
**Files to create:** [list with brief purpose]
**Files to modify:** [list with what changes]
**Change order (dependencies first):**
1. {file} — {what and why first}
2. {file} — {depends on step 1}
**Risks:** {shared files with parallel tasks, if any}
- Scope: ONLY files of this task. Do not analyze other tasks.
- **Checkpoint:** Emit PHASE_3 checkpoint with structured `blueprint` payload:
`{ "blueprint": { "change_order": [{ "file": "...", "action": "create|modify", "reason": "..." }] } }`
Guard blocks PHASE_4 if blueprint is missing from the checkpoint.
Step 3: Start Work
- Set task to In Progress, update kanban
Step 4: Implement
- 4a Pattern Reuse: IF creating new file/utility, Grep src/ for existing similar patterns
(error handlers, validators, HTTP wrappers, config loaders). Reuse if found.
- 4b Follow task plan/AC, apply KISS/YAGNI
- 4c Architecture Guard: IF creating service function: (1) 3+ side-effect categories in **leaf** function → split (EXCEPT orchestrator functions that delegate sequentially — these are expected to have 3+ categories);
(2) get_*/find_*/check_* naming → verify no hidden writes; (3) 3+ service imports in **leaf** function → flatten (orchestrator imports are expected)
(4) **Frontend Guard (conditional):** IF affected files include `.tsx/.vue/.svelte/.html/.css` → **MANDATORY READ:** Load `references/frontend_design_guide.md`. Load project's design_guidelines.md if exists (design tokens source of truth). Verify: one composition per viewport; max 2 typefaces + 1 accent color; cards only when interaction requires; motion max 2-3 purposeful; WCAG 2.1 AA contrast (4.5:1 text, 3:1 UI elements)
- Update docs and existing tests if impacted
- Execute verify: methods from task AC (test/command/inspect)
Step 5: Quality
- Run typecheck and lint (or project equivalents)
- 5b Blueprint Completion: compare actual changes to blueprint; emit blueprint_status in PHASE_6 checkpoint
Step 6: Finish
- Set task to To Review, update kanban
- Add summary comment (changes, tests, docs)
getTask); read linked guides/manuals/ADRs/research; auto-discover team/config if needed.
2b) Goal gate: MANDATORY READ: Load references/goal_articulation_gate.md — Complete the 4-question gate (<=25 tokens each). State REAL GOAL (deliverable as subject), DONE LOOKS LIKE, NOT THE GOAL, INVARIANTS & HIDDEN CONSTRAINTS.
2c) Implementation Blueprint: From task "Affected Components", find actual file paths via Glob/Grep or narrow inspect_path(path=<component dir>). Read key sections of each file. If task changes existing code in supported languages, build graph context once (index_project) and use path-scoped find_symbols / inspect_symbol for exact symbol identity plus analyze_edit_region before editing non-trivial ranges. If symbol discovery is truncated, refine to name + file or workspace_qualified_name before planning from it. Output structured plan: files to create/modify, change order (dependencies first), risks (shared files with parallel tasks, external callers, public API surfaces). Scope: this task only.updateStatus); move it in kanban (keep Epic/Story indent).src/ for existing patterns (error handling, validation, config access). Reuse if found; if not reusable, document rationale in code comment. For edits to existing functions, classes, routes, or middleware, run analyze_edit_region first and account for external callers, clone siblings, downstream flow, and public API risk. Follow checkboxes/plan; keep it simple; avoid hardcoded values; reuse existing components; update docs noted in Affected Components; update existing tests if impacted (no new tests here). Before creating service functions, apply Architecture Guard (cascade depth, interface honesty, flat orchestration; for frontend files: MANDATORY READ references/frontend_design_guide.md, load design_guidelines.md if exists, verify composition/typography/WCAG rules). After implementation, execute verify: methods from task AC: test → run specified test; command → execute and check output; inspect → verify file/content exists. If any verify fails → fix before proceeding.{ "blueprint_status": { "planned_count": N, "completed": [...], "skipped": [{"file":"...","justification":"..."}], "added": [{"file":"...","justification":"..."}], "completion_pct": N } }. Guard blocks PHASE_7 if missing.updateStatus); update kanban to To Review; add summary comment (what changed, tests run, docs touched).Context: Self-assessment before To Review reduces review round-trips and catches obvious issues early.
MANDATORY READ: Load references/code_efficiency_criterion.md — self-check before submission.
Before setting To Review, verify all items:
| # | Check | Verify |
|---|---|---|
| 0 | AC verified | Each AC verify: method executed with pass evidence |
| 1 | Approach alignment | Implementation matches Story Technical Approach |
| 2 | Clean code | No dead code, no backward-compat shims, unused imports removed |
| 3 | Config hygiene | No hardcoded creds/URLs/magic numbers |
| 4 | Docs updated | Affected Components docs reflect changes |
| 5 | Tests pass | Existing tests still pass after changes |
| 6 | Pattern reuse | New utilities checked against existing codebase; no duplicate patterns introduced |
| 7 | Architecture guard | Cascade depth <= 2 (leaf functions); no hidden writes in read-named functions; no service chains >= 3 in leaf functions (orchestrator imports exempt). Frontend files: composition, typography, WCAG per references/frontend_design_guide.md |
| 8 | Destructive op safety | If task has "Destructive Operation Safety" section: (1) backup step executed/planned before destructive code, (2) rollback mechanism exists in code, (3) environment guard present, (4) preview/dry-run evidence attached or referenced |
| 9 | Code efficiency | No unnecessary intermediates, verbose patterns replaced by language idioms, no boilerplate framework handles (per references/code_efficiency_criterion.md) |
| 10 | Blueprint complete | All blueprint items completed or skipped with justification; blueprint_status emitted in PHASE_6 checkpoint |
MANDATORY READ: Load references/destructive_operation_safety.md for severity classification and safety requirements.
HITL Gate: IF task severity = CRITICAL (per destructive_operation_safety.md loaded above): Use AskUserQuestion to confirm before marking To Review: "Task contains CRITICAL destructive operation: {operation}. Backup plan: {plan}. Proceed?" Do NOT mark To Review until user confirms.
If any check fails: Fix before setting To Review. Do not rely on reviewer to catch preventable issues.
MANDATORY READ: Load references/coordinator_summary_contract.md, references/worker_runtime_contract.md, references/task_worker_runtime_contract.md
Shared contract:
summary_kind=task-statusrunId and summaryArtifactPathrunId and exact summaryArtifactPath before the worker writes its validated summaryMonitor (2.1.98+): When verification commands expected >30s, use Monitor. Fallback: Bash(run_in_background=true).
verify: method executed with pass evidence.references/environment_state_contract.mdreferences/storage_mode_detection.mddocs/guides/, docs/manuals/, docs/adrs/, docs/research/docs/tasks/kanban_board.mdVersion: 3.0.0 Last Updated: 2025-12-23