# Harness Executor > Execute development tasks autonomously with self-validation. Auto-bootstraps harness via harness-creator if missing. Use when the user asks to implement features, fix bugs, refactor code, execute plans, or make any code change in an existing or new codebase. - Skill: `higress-group/harness-executor` (Agent Skill, multi-file: 31 files) - Install (CLI): `npx skillmds@latest add higress-group/harness-executor` - Raw SKILL.md: https://api.skillmd.com/api/skills/higress-group/harness-executor/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: higress-group (https://skillmd.com/u/higress-group) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/higress-group/harness-executor --- # Harness Executor Execute development tasks autonomously: setup → plan → execute → validate → verify → record → present. > **Core Philosophy**: "The Agent Harness is the Operating System. The LLM is just the CPU." Verify your changes mechanically through automated checks, not hope. > **Architecture Principle**: **Coordinator manages state, Subagent executes code.** The coordinator spawns subagents for code changes and verification. The subagent never calls task_state.py. ## Script Execution This skill bundles helper scripts in its `scripts/` subdirectory. Before running any script, determine this skill's installation directory from the path of this SKILL.md file, and set: ```bash SKILL_DIR="" ``` Then call scripts as: `python3 "$SKILL_DIR/scripts/xxx.py"`. All bash examples below assume `SKILL_DIR` has been set this way. --- ## Execution Flow Every task follows the same seven steps. **No exceptions, no shortcuts.** ``` COORDINATOR ═══════════════════════════════════════════ 1. SETUP bootstrap → check interrupted → query memory → load context 2. PLAN scope the work → init state → (multi-phase: plan file + user approval) 3. EXECUTE spawn executor subagent → make code changes → checkpoint 4. VALIDATE static validation (build, lint, test) 5. VERIFY spawn verifier subagent → functional verification (MANDATORY) 6. RECORD task_state.py complete → episodic memory → AutoHarness 7. PRESENT results summary to user ═══════════════════════════════════════════ ``` > ⚠️ **CRITICAL**: Steps 4 and 5 are BOTH mandatory for ALL tasks. Static validation proves code compiles. Functional verification proves code *works*. Never skip Step 5. --- ## Step 1: Setup ### 1.1 Bootstrap Harness ```bash test -f AGENTS.md && echo "HARNESS_EXISTS=true" || echo "HARNESS_EXISTS=false" ``` If `HARNESS_EXISTS=false`: invoke `Skill(skill="harness-creator")` first. ### 1.2 Check Interrupted Tasks ```bash python3 "$SKILL_DIR/scripts/task_state.py" list ``` If an `in_progress` task matches the current request → Resume Protocol (see below). ### 1.3 Query Memory ```bash if [ -d "harness/memory" ]; then python3 "$SKILL_DIR/scripts/memory_query.py" search "" --json 2>/dev/null || echo '{"results": []}' else echo "No memory store yet — skipping" fi ``` ### 1.4 Load Context Read: `AGENTS.md`, `docs/ARCHITECTURE.md`, `docs/DEVELOPMENT.md`. Extract: build command, test command, lint command, validation script path. --- ## Step 2: Plan **All tasks**: Identify files to modify/create, decide the approach, initialize task state. **Multi-phase tasks** (touching 3+ files or requiring sequential changes): Write a plan file, get user approval. ### Initialize Task State (all tasks) ```bash TASK_ID=$(python3 "$SKILL_DIR/scripts/task_state.py" init "" \ --phases \ --description "" \ --plan-path "docs/exec-plans/active/YYYY-MM-DD-.md") # optional for single-phase echo "Task ID: $TASK_ID" ``` ### Multi-Phase Plan File ```bash mkdir -p docs/exec-plans/active ``` Write to `docs/exec-plans/active/YYYY-MM-DD-.md`: ```markdown # [Task Name] **Created**: YYYY-MM-DD ## Goal One sentence describing what success looks like. ## Scope - **Files to modify**: [list] - **Files to create**: [list] ## Phases ### Phase 1: [Name] - [ ] Step 1.1: [action] - **Validates with**: `[command]` ### Phase 2: [Name] - [ ] Step 2.1: [action] - **Validates with**: `[command]` ``` ### Multi-Phase User Approval Use `AskUserQuestion` with options: **Approve** / **Approve with changes** / **Reject**. --- ## Step 3: Execute Spawn an executor subagent to make code changes. **The coordinator never writes code directly.** ### Executor Subagent Prompt ``` Agent( description="Execute: [task-name]", prompt=""" You are a code executor. Your ONLY job is to make code changes. ## Task [task description] ## Project Root [absolute path] ## Files to Modify/Create [explicit list] ## Validation Command After making changes, run: ``` [project-specific command, e.g., go build ./... && make lint-arch] ``` ## Prior Lessons [paste lessons from memory_query, or "none"] ## Output Format Return this JSON block at the end of your response: ```json { "status": "success | failed | blocked", "summary": "one paragraph describing what you did", "files_changed": ["file1.go", "file2.go"], "files_created": ["new_file.go"], "validation_result": "pass | fail", "validation_output": "relevant output if failed", "lessons": ["any insights worth remembering"], "blockers": ["if blocked, describe what's stopping you"] } ``` ## Rules - Focus ONLY on making code changes - Do NOT manage task state or checkpoints — the coordinator handles that - If validation fails, fix and retry (max 3 attempts) - If blocked, return with status "blocked" """ ) ``` ### Checkpoint (after successful executor return) ```bash python3 "$SKILL_DIR/scripts/task_state.py" checkpoint \ --task-id "$TASK_ID" \ --phase \ --summary "" \ --files-changed \ --decisions '["key decisions from subagent lessons"]' ``` ### Failure Handling | Subagent Status | Action | |---|---| | `success` | Continue to Step 4 | | `failed` | Retry with additional context (max 2 retries) | | `blocked` | Escalate to user | --- ## Step 4: Validate (Static) Run static validation to ensure code compiles and passes lints/tests. ```bash if [ -f "scripts/validate.py" ]; then python3 scripts/validate.py . else # Use commands from docs/DEVELOPMENT.md && && fi ``` If static validation fails: 1. Analyze error output 2. Return to Step 3 with fix instructions (spawn executor again) 3. Max 2 retries, then escalate to user --- ## Step 5: Verify (Functional) — MANDATORY > ⚠️ **This step is MANDATORY for ALL tasks.** Do NOT skip to Step 6 without completing verification. Static checks only prove code compiles. Functional verification proves code *works* — by starting the actual application, making real HTTP requests, and verifying observable behavior. ### 5.1 Design Verification Scenarios Based on what changed, design 1-3 task-specific scenarios (see `references/scenario-design-guide.md`): | Change Type | Scenarios to Design | |---|---| | New endpoint | Create success, validation error, persistence check | | Modified endpoint | New behavior works, old behavior unchanged | | New validation | Valid input accepted, invalid input rejected | | Permission change | Authorized user succeeds, unauthorized user rejected | | Bug fix | The specific bug is fixed | ### 5.2 Spawn Verifier Subagent ``` Agent( description="Functional Verifier: [task-name]", prompt=""" You are a Functional Verifier agent. Read the verifier guide at: $SKILL_DIR/agents/verifier.md ## Task Context - Project root: [absolute path] - Task description: [what was implemented] - Files changed/created: [list] ## Environment Context (from environment.json if exists) - Startup: [command], Readiness: [check config] - Services: [databases, caches], Env Vars: [required vars] ## Scenarios to Verify [your designed scenarios as JSON array] ## Your Responsibilities 1. Start the application server 2. Execute ALL scenarios 3. For each: verify behavior AND side effects with real HTTP requests 4. Stop the server cleanly 5. Save results to: harness/trace/verification-report.json ## Output Requirements Your verification-report.json MUST include: - server.started: true (prove you started the app) - At least one scenario with request/response evidence """ ) ``` ### 5.3 Handle Verifier Result | Result | Action | |---|---| | `pass` | Continue to Step 6 | | `partial` | Fix failing scenarios related to task, log unrelated as warnings | | `fail` | Return to Step 3 with fix instructions, max 2 retries, then escalate | ### 5.4 If Verification Cannot Run If the application cannot be started (no server, library project, missing infrastructure), write a skip report: ```bash mkdir -p harness/trace cat > harness/trace/verification-report.json << 'EOF' { "overall_status": "skip", "skip_reason": "[explain why: e.g., 'Library project with no runnable server', 'Missing required database']", "server": {"started": false}, "task_specific_scenarios": [], "summary": {"task_specific_total": 0, "task_specific_passed": 0, "pass_rate": 0} } EOF ``` --- ## Step 6: Record & Complete ### Complete Task ```bash python3 "$SKILL_DIR/scripts/task_state.py" complete \ --task-id "$TASK_ID" \ --summary "Completed: " \ --files-changed file1 file2 \ --files-created new_file \ --validation '{"build": "pass", "lint": "pass", "test": "pass"}' \ --lessons '["lesson1", "lesson2"]' ``` > ⚠ **Completion Gate**: `complete` checks for `harness/trace/verification-report.json`. It **rejects** if: > - File is missing (Step 5 was skipped) > - Report lacks `server.started` or HTTP evidence (unless `overall_status: "skip"`) **Move plan file** (if exists): ```bash mkdir -p docs/exec-plans/completed mv "docs/exec-plans/active/.md" "docs/exec-plans/completed/" 2>/dev/null || true ``` ### AutoHarness Check ```bash TASK_COUNT=$(python3 "$SKILL_DIR/scripts/task_state.py" list --json 2>/dev/null | \ python3 -c "import sys,json; d=json.load(sys.stdin); print(len([t for t in d if t.get('status')=='completed']))" 2>/dev/null || echo 0) if [ "$TASK_COUNT" -ge 3 ]; then python3 "$SKILL_DIR/scripts/harness_critic.py" --since 7d 2>/dev/null || true fi ``` --- ## Step 7: Present Results ``` ## Task Complete ### Changes Made - Modified `path/to/file` — [what changed] - Created `path/to/new-file` — [purpose] ### Validation Results - Build: PASS | Lint: PASS | Test: PASS ### Verification Results - Server started: YES - Scenarios: [N] designed, [N] passed - Evidence: [summary of what was verified] ### Lessons Recorded - [aggregated lessons] ### Next Steps 1. Create PR 2. Commit to current branch ``` --- ## Resume Protocol When Step 1.2 finds an interrupted task: ```bash python3 "$SKILL_DIR/scripts/task_state.py" show --task-id --json ``` Resume from the last successful checkpoint: - Read `harness/tasks//state/context.json` - Pass context to subagent for the next phase - Continue the execution loop --- ## Reference Files | File | When to Read | Contents | |---|---|---| | `agents/verifier.md` | Step 5.2: spawn Functional Verifier | Verifier subagent instructions, bootstrap protocol, output format | | `references/scenario-design-guide.md` | Step 5.1: designing scenarios | Scenario design patterns and examples | | `references/functional-verification-guide.md` | Understanding the verification flow | Static validation → Functional Verifier architecture | | `references/environment-schema.md` | Reading environment.json | environment.json contract: startup, services, env_vars | | `references/validation-guide.md` | Step 4: static validation | Validation order, error recovery | | `references/state-management.md` | Task state operations | task.json/context.json/checkpoint schemas | --- ## Guardrails These are hard constraints. Violating them causes task completion to fail. | Guardrail | Enforced By | Consequence | |---|---|---| | Must spawn verifier subagent | `complete` command | Rejects without verification-report.json | | Must have HTTP evidence | `complete` command | Rejects if report lacks request/response | | Must start application | `complete` command | Rejects if server.started=false (unless skip) | If you find yourself wanting to bypass these guardrails, stop and reconsider. The guardrails exist because skipping verification is the #1 cause of "it compiled but doesn't work" bugs.