Agent Harness
You are a harness operator, not a hero. The loop — not your optimism — decides when work
is done. Your job: compile the goal into tasks with checks, execute one task at a time,
let the controller adjudicate verification, and stop when the state machine says stop.
The contract
GOAL → goal_compiler → PLAN → loop_controller: [execute → verify]* → CLOSE
↑______retry (≤ max_attempts, changed approach)
└── ESCALATE on exhausted budgets — never fake success
Three layers, all JSON: a committed per-domain manifest (what skills/tools/checks
exist), a per-goal plan (which tasks, which verifications, what "done" means), and a
per-run state file (the single source of truth; a fresh session resumes from it alone).
Quick start
# 0. Pick the domain manifest (18 committed under assets/harnesses/, e.g. engineering-team.json)
ls assets/harnesses/
# 1. Compile the goal (refuses vague goals with exit 3 + forcing questions)
python3 scripts/goal_compiler.py \
--goal "audit the payments service and design an SLO with an error budget" \
--manifest assets/harnesses/engineering.json --out plan.json
# 2. Initialize the loop state
python3 scripts/loop_controller.py init --plan plan.json --state .agent-harness/state.json
# 3. Drive the loop — repeat until directive is "close" or "escalate"
python3 scripts/loop_controller.py next --state .agent-harness/state.json
# → {"action": "execute", "task": "T1", ...}: open the task's skill (SKILL.md at
# skill_path), do the work with its tools, then:
python3 scripts/loop_controller.py record --state .agent-harness/state.json \
--task T1 --phase execute --exit-code 0
# → the controller runs the task's checks ITSELF (subprocess, timeout, evidence log):
python3 scripts/loop_controller.py verify --state .agent-harness/state.json --task T1 --cwd <repo-root>
# 4. Close — refused (exit 4) while any task is unverified and unwaived
python3 scripts/loop_controller.py close --state .agent-harness/state.json
Regenerate a manifest after skills change (diff-stable, CI-checkable):
python3 scripts/harness_manifest_builder.py --domain engineering-team \
--repo-root <repo-root> --out-dir assets/harnesses --no-timestamp
Hard rules
- Never adjudicate your own verification.
verify runs the checks via subprocess;
a passing record --phase verify without --evidence is rejected (exit 6). You do not
get to declare a task verified.
- Never modify a gate you are judged by. Check commands come from the manifest/plan.
Editing a check to make it pass is the reward-hacking failure mode
(see references/verification_discipline.md [blocked]) — same
invariant as autoresearch-agent's locked evaluator.
- One task at a time, writes serialized. Parallelize reading and judging, never two
tasks writing the same artifact (references/agentic_loop_canon.md [blocked]).
- Retry means a changed approach. Same command + same input = same failure. The retry
directive says so; honor it.
- Budgets are terminal states, not suggestions.
max_attempts_per_task → escalated
(exit 2); max_loop_iterations → escalate (exit 5). Exhausted budgets are never
reported as success — a human waives (close --waive T3 --reason "..."), you don't.
- Fresh context beats long context. Every
next directive is executable by a new
session reading only the plan + state files. Long-running goals: run each iteration as
its own session against the durable state.
- State lives in
.agent-harness/ — never in .agenthub/, .autoresearch/, or
docs/TC/ (those belong to sibling skills).
- Plan and state files are a trust boundary.
verify shell-executes each task's
check command; only run the harness on plan/state files you or goal_compiler.py
produced, never on files from untrusted input (see
references/verification_discipline.md [blocked]).
Forcing questions (ask before compiling; one per turn, with a recommended answer)
| # | Question | Recommended answer | Why (canon) |
|---|
| 1 | What single observable outcome means DONE? | A named artifact + a command that exits 0 against it | Verifier's law: invest in verifiability first |
| 2 | Which domain harness applies? | The domain whose skills name the deliverable; if two, run two sequential loops | Orchestrator-workers: scoped objectives beat mega-goals |
| 3 | What must NOT change? | List no-touch paths; put them in the goal text so the compiler's plan inherits them | Boundaries are part of a subagent spec |
| 4 | Who reviews escalations, and how fast? | A named human; escalations block the loop by design | Approval-required is a terminal state, not a nuisance |
| 5 | What is the iteration budget? | Default 12 loop iterations / 3 attempts per task; raise only with a reason | Caps are runtime errors, not advice (OpenAI SDK max_turns) |
Exit codes (branch on these mechanically)
| Code | Tool | Meaning |
|---|
| 0 | all | OK / directive emitted |
| 2 | loop_controller | Escalation required — a human must review the evidence log |
| 3 | goal_compiler | Goal too vague — answer the forcing questions, recompile |
| 4 | goal_compiler / loop_controller | No skill matched / close refused (unverified tasks) |
| 5 | loop_controller | Global iteration cap reached |
| 6 | loop_controller | Invalid transition (recording on verified task, evidence missing, unknown task) |
Verifiable success
python3 scripts/harness_manifest_builder.py --sample, scripts/goal_compiler.py --sample,
and scripts/loop_controller.py --sample all exit 0.- A vague goal (
--goal "make it better") exits 3 and prints forcing questions.
loop_controller.py close on a state with an unverified task exits 4.- The demo loop in
loop_controller.py --sample shows a verify failure consuming an attempt
and the loop still closing only after a passing verify with evidence.
Related skills
- workflow-builder: authoring deterministic
.js scripts for Claude Code's Workflow
tool. NOT for goal-to-close loop state (this skill).
- agenthub: N parallel agents competing on ONE task in git worktrees. Use it inside a
harness task that wants competing attempts.
- autoresearch-agent: metric optimization of a single file against a locked evaluator.
Use it when a task's done_when is "metric improves".
- tc-tracker: per-code-change lifecycle records. Use for change bookkeeping; the harness
state file is per-goal, not per-change.
- loop-library: discover/audit published loop recipes conversationally. This skill is the
executable enforcement of that vocabulary.
- ship-gate / self-eval / spec-driven-workflow: plug in as close-time checks inside a
task's
verification[].
See references/domain_harness_design.md [blocked] for the
three-layer architecture, the reuse map, and how to raise a domain's harness quality.