Harness Generation
You seed a minimal, auditable harness v0 — the scaffold around a model (prompts,
tools, skills, memory hooks, lifecycle, verification interface, governance). You do
not evolve harnesses; route ongoing improvement to harness-evolution.
Trigger Discipline
Auto-invoke when chained from project-setup 6c, retroactive-project-setup, harness-engineering Step 0, or setup-evaluation harness FAIL. See harness-engineering/references/harness-readiness-gate.md.
Hard Rules
Never generate a harness without a versioned component manifest (docs/harness/manifest.json).
Never ship a pre-tuned bloated harness — v0 is minimal; components earn their place via measured rollouts (AHE).
Never rely on prompt-only harness — tools, middleware, skills, and eval interface are required surfaces (AHE ablation).
Never overwrite user-edited harness files without manifest drift check — refuse or merge explicitly.
Never claim self-improving without eval interface stub + pointer to harness-evolution.
Never embed external repo URLs in generated artifacts — distill patterns locally.
Workflow
Step 1 — Classify delivery context
| Context |
v0 focus |
| agent-loom skill library project |
Skill routing, AGENTS.md orchestration map, eval stub for skill quality |
| Consumer app repo |
AGENTS.md, .agents/skills/, forbidden paths, key commands |
| Legacy repo (no AGENTS.md) |
Gap-fill only — pair with retroactive-project-setup first |
| Multi-agent chain planned |
Manifest only — topology is agent-builder, not this skill |
Step 2 — Inventory repo (silent)
Read: manifests, existing AGENTS.md, .agents/skills/, CI configs, docs/memory/,
docs/evals/, docs/harness/. Auto-extract commands per project-setup Step 1b.
Step 3 — Emit component manifest
Write docs/harness/manifest.json per references/component-manifest.md:
seven orthogonal components (prompt, tools, middleware, skills, sub-agents, memory, governance),
each with path, version, sha256, and generated|user-edited status.
Step 4 — Scaffold artifacts
Apply patterns from references/scaffold-patterns.md:
- Prompt / routing — merge into
AGENTS.md or create harness section; keep ≤150 lines total.
- Skills — ensure Skill Invocation block present; list installed skills in Orchestration Map.
- Tools — document MCP/tool surfaces in manifest; stub
docs/harness/tools.md if needed.
- Governance — forbidden paths, allowed-write scopes, verifier sandbox rules.
- Eval interface stub —
docs/harness/eval-interface.md + empty docs/harness/tasks.json shape
(file_phrase + command checks per metaharness pattern).
- Environment bootstrap — compact snapshot block (stack, key commands, git branch) for meta-agents.
If project-setup already ran: merge, never replace user interview content.
Step 5 — Drift gate
Document harness sync --check equivalent: compare manifest hashes to disk; flag user-edited files
skipped on re-run. CI recommendation in manifest notes.
Step 6 — Hand off
| Next need |
Route |
| Full AGENTS.md interview missing |
project-setup |
| Eval rubric + regression suite |
eval-rubric-design → eval-pipeline |
| Improve harness from failures |
harness-evolution (requires eval harness) |
| Multi-agent design |
agent-builder (orthogonal) |
Append to docs/skill-outputs/SKILL-OUTPUTS.md. Log harness version v0 in docs/memory/current-state.md if memory suite installed.
Gotchas
- Minimal seed is mandatory. Pre-tuned harnesses contaminate attribution — every component added later must justify itself with traces (Self-Harness, AHE).
- AGENTS.md must stay lean. RHO/Codex paths cap combined project docs ~32KB — routing belongs in skills, detail in L3 refs.
- Harness ≠ agent topology.
agent-builder designs who talks to whom; this skill designs what files/tools/prompts wrap the model.
- Deterministic scaffold beats one-shot LLM init. Inspect → plan → staged writes → manifest (harnessforge pattern); LLM fill is optional fallback only.
- Blueprint validators that shell out are a trust boundary — document, never auto-run untrusted commands.
Output Format
Harness generation complete
Version: v0
Context: [library | consumer | legacy-gap-fill]
Manifest: docs/harness/manifest.json
Artifacts: [list paths]
Eval stub: docs/harness/eval-interface.md
Drift check: [documented command]
Next: [eval-pipeline | harness-evolution | project-setup]
Example
Common Rationalizations
| Excuse |
Reality |
| "AGENTS.md is enough" |
No manifest, eval stub, or governance = not a harness v0 |
| "Skip eval stub for now" |
harness-evolution hard-fails without it |
| "Copy external harness README" |
Distill patterns; secure-scan; no URL embed |
| "Let LLM write the whole harness" |
Deterministic manifest + merge beats opaque generation |
| "Agent-builder already ran" |
Topology ≠ harness files — run both |
Verification
Red Flags
- Harness v0 bloated with speculative prompts/tools
- User-edited files overwritten without merge
- No eval interface stub when evolution is planned
- External SKILL.md vendored wholesale
Prune Log
Last pruned: 2026-07-05
- Deep learn-from: scaffold-patterns L3 — drift CI, interface validation, AHE sandbox
Impact Report
Harness v0 generated: [context]
Manifest: docs/harness/manifest.json | Components: 7
Eval stub: [yes/no] | Merged AGENTS.md: [yes/no]
Files created: [count] | Next route: [skill]
Reference Files
references/component-manifest.md — seven components, JSON schema, ETCLOVG mapreferences/scaffold-patterns.md — inspect→render, drift CI, bootstrap snapshotreferences/examples.md — library project + consumer repo worked examples
1---2name: harness-generation3description: Seed minimal agent harness v0 — manifest, eval checks stub, governance. AUTO-INVOKED after project-setup or retroactive-project-setup when docs/harness/manifest.json is missing. Also triggers on: generate harness, scaffold agents, agent bootstrap, first time agents in this repo, new project agent setup, set up agent harness, agent onboarding files, missing agent configuration, agent instructions setup, make agents read project rules, agent reliability setup, agents not configured. Pairs with project-setup. Evolution is harness-evolution.4license: MIT5---67# Harness Generation89You seed a **minimal, auditable harness v0** — the scaffold around a model (prompts,10tools, skills, memory hooks, lifecycle, verification interface, governance). You do11not evolve harnesses; route ongoing improvement to `harness-evolution`.1213## Trigger Discipline1415**Auto-invoke** when chained from `project-setup` 6c, `retroactive-project-setup`, `harness-engineering` Step 0, or `setup-evaluation` harness FAIL. See `harness-engineering/references/harness-readiness-gate.md`.1617## Hard Rules1819Never generate a harness without a versioned **component manifest** (`docs/harness/manifest.json`).20Never ship a pre-tuned bloated harness — v0 is minimal; components earn their place via measured rollouts (AHE).21Never rely on prompt-only harness — tools, middleware, skills, and eval interface are required surfaces (AHE ablation).22Never overwrite user-edited harness files without manifest drift check — refuse or merge explicitly.23Never claim self-improving without eval interface stub + pointer to `harness-evolution`.24Never embed external repo URLs in generated artifacts — distill patterns locally.2526---2728## Workflow2930### Step 1 — Classify delivery context3132| Context | v0 focus |33|---------|----------|34| agent-loom skill library project | Skill routing, AGENTS.md orchestration map, eval stub for skill quality |35| Consumer app repo | AGENTS.md, `.agents/skills/`, forbidden paths, key commands |36| Legacy repo (no AGENTS.md) | Gap-fill only — pair with `retroactive-project-setup` first |37| Multi-agent chain planned | Manifest only — topology is `agent-builder`, not this skill |3839### Step 2 — Inventory repo (silent)4041Read: manifests, existing `AGENTS.md`, `.agents/skills/`, CI configs, `docs/memory/`,42`docs/evals/`, `docs/harness/`. Auto-extract commands per `project-setup` Step 1b.4344### Step 3 — Emit component manifest4546Write `docs/harness/manifest.json` per `references/component-manifest.md`:47seven orthogonal components (prompt, tools, middleware, skills, sub-agents, memory, governance),48each with path, version, sha256, and `generated|user-edited` status.4950### Step 4 — Scaffold artifacts5152Apply patterns from `references/scaffold-patterns.md`:53541. **Prompt / routing** — merge into `AGENTS.md` or create harness section; keep ≤150 lines total.552. **Skills** — ensure Skill Invocation block present; list installed skills in Orchestration Map.563. **Tools** — document MCP/tool surfaces in manifest; stub `docs/harness/tools.md` if needed.574. **Governance** — forbidden paths, allowed-write scopes, verifier sandbox rules.585. **Eval interface stub** — `docs/harness/eval-interface.md` + empty `docs/harness/tasks.json` shape59 (file_phrase + command checks per metaharness pattern).606. **Environment bootstrap** — compact snapshot block (stack, key commands, git branch) for meta-agents.6162If `project-setup` already ran: **merge**, never replace user interview content.6364### Step 5 — Drift gate6566Document `harness sync --check` equivalent: compare manifest hashes to disk; flag user-edited files67skipped on re-run. CI recommendation in manifest notes.6869### Step 6 — Hand off7071| Next need | Route |72|-----------|-------|73| Full AGENTS.md interview missing | `project-setup` |74| Eval rubric + regression suite | `eval-rubric-design` → `eval-pipeline` |75| Improve harness from failures | `harness-evolution` (requires eval harness) |76| Multi-agent design | `agent-builder` (orthogonal) |7778Append to `docs/skill-outputs/SKILL-OUTPUTS.md`. Log harness version `v0` in `docs/memory/current-state.md` if memory suite installed.7980---8182## Gotchas8384- **Minimal seed is mandatory.** Pre-tuned harnesses contaminate attribution — every component added later must justify itself with traces (Self-Harness, AHE).85- **AGENTS.md must stay lean.** RHO/Codex paths cap combined project docs ~32KB — routing belongs in skills, detail in L3 refs.86- **Harness ≠ agent topology.** `agent-builder` designs who talks to whom; this skill designs what files/tools/prompts wrap the model.87- **Deterministic scaffold beats one-shot LLM init.** Inspect → plan → staged writes → manifest (harnessforge pattern); LLM fill is optional fallback only.88- **Blueprint validators that shell out are a trust boundary** — document, never auto-run untrusted commands.8990---9192## Output Format9394```95Harness generation complete96Version: v097Context: [library | consumer | legacy-gap-fill]98Manifest: docs/harness/manifest.json99Artifacts: [list paths]100Eval stub: docs/harness/eval-interface.md101Drift check: [documented command]102Next: [eval-pipeline | harness-evolution | project-setup]103```104105---106107## Example108109<examples>110 <example>111 <input>Generate a harness for this React monorepo — we have AGENTS.md from project-setup.</input>112 <output>113Harness generation complete114Version: v0 | Context: consumer115Manifest: docs/harness/manifest.json (7 components, all generated)116Merged: Skill Invocation + Orchestration Map preserved from interview117Created: docs/harness/eval-interface.md, docs/harness/tasks.json (stub), docs/harness/governance.md118Next: eval-rubric-design to define harness regression dimensions119 </output>120 </example>121</examples>122123## Common Rationalizations124125| Excuse | Reality |126|--------|---------|127| "AGENTS.md is enough" | No manifest, eval stub, or governance = not a harness v0 |128| "Skip eval stub for now" | harness-evolution hard-fails without it |129| "Copy external harness README" | Distill patterns; secure-scan; no URL embed |130| "Let LLM write the whole harness" | Deterministic manifest + merge beats opaque generation |131| "Agent-builder already ran" | Topology ≠ harness files — run both |132133## Verification134135- [ ] `docs/harness/manifest.json` exists with 7 components and hashes136- [ ] Eval interface stub + tasks.json shape present137- [ ] AGENTS.md ≤150 lines; user content preserved on merge138- [ ] Governance forbidden paths documented139- [ ] SKILL-OUTPUTS.md appended140141## Red Flags142143- Harness v0 bloated with speculative prompts/tools144- User-edited files overwritten without merge145- No eval interface stub when evolution is planned146- External SKILL.md vendored wholesale147148## Prune Log149Last pruned: 2026-07-05150- Deep learn-from: scaffold-patterns L3 — drift CI, interface validation, AHE sandbox151152## Impact Report153154```155Harness v0 generated: [context]156Manifest: docs/harness/manifest.json | Components: 7157Eval stub: [yes/no] | Merged AGENTS.md: [yes/no]158Files created: [count] | Next route: [skill]159```160161## Reference Files162163- `references/component-manifest.md` — seven components, JSON schema, ETCLOVG map164- `references/scaffold-patterns.md` — inspect→render, drift CI, bootstrap snapshot165- `references/examples.md` — library project + consumer repo worked examples
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