Build, audit, and improve harnesses that make AI coding agents reliable: AGENTS.md/CLAUDE.md instruction files, feature/state tracking, verification gates, scope boundaries, session handoff, memory persistence, context budgets, tool-permission safety, and multi-agent coordination. Use this whenever

Harness Creator Use this skill to make a repository easier for coding agents to start, stay in scope, verify work, and resume across sessions. Keep the harness small enough that agents actually follow it. Not for model selection, prompt tuning in isolation, chat UI design, or general app architecture. Core Model Every useful coding agent harness has five subsystems: Subsystem Minimal artifact Purpose Instructions AGENTS.md or CLAUDE.md Startup path, working rules, definition of done State feature list.json , progress.md Current feature, status, evidence, next step Verification init.sh or documented commands Tests/checks the agent must run before claiming done Scope Feature dependencies and done criteria Prevents overreach and half finished work Lifecycle session handoff.md , end of session routine Makes the next session restartable First Move 1. Inspect what already exists: instruction files, feature/state files, verification commands, docs, package manifests. 2. Ask only for missing context that cannot be inferred safely: target agent, desired file name, tolerance for structure, and whether overwriting is allowed. 3. Prefer a minimal harness first. Add memory, tool safety, multi agent, or benchmark details only when the user's problem calls for them. Common Tasks Create a harness Use the bundled script when working on a local repository: Options: agent file CLAUDE.md for Claude oriented projects. package manager npm pnpm yarn bun when detection is wrong. commands "cmd one,cmd two" for custom verification. force only after confirming overwrites are acceptable. Then explain what was created and how the user should replace placeholder feature entries. Audit an existing harness Run: Report the five subsystem scores, the lowest scoring area, and the first 2 3 changes that would improve reliability. Treat the lowest score as a candidate bottleneck; confirm with failures, logs, or task outcomes before claiming causality. Produce a report Use when the user wants a shareable assessment: Be clear that this is a structural benchmark. The benchmark first runs a self check — it scaffolds a throwaway harness and validates it, proving the bundled scripts work end to end — then scores the target and eval coverage. Real effectiveness still needs before/after agent sessions on representative tasks. When to Read References Load only the reference needed for the user's problem: Memory across sessions: [Memory Persistence](references/memory persistence pattern.md) Reusable workflows as skills: [Skill Runtime](references/skill runtime pattern.md) Permissions, tools, concurrency: [Tool Registry & Safety](references/tool registry pattern.md) Context budget and progressive disclosure: [Context Engineering](references/context engineering pattern.md) Delegation and parallel agents: [Multi Agent Coordination](references/multi agent pattern.md) Hooks, startup, long running work: [Lifecycle & Bootstrap](references/lifecycle bootstrap pattern.md) Non obvious failure modes: [Gotchas](references/gotchas.md) Design Rules Keep the root instruction file short: routing and invariants, not a full manual. Put project facts in project docs, not in the skill. Make verification commands explicit and runnable. Require evidence before marking a feature done. Use one active feature unless the harness has explicit multi agent ownership boundaries. Prefer append/update state files over relying on chat history. Never hide destructive behavior in scripts; overwrites require explicit user approval. Deliverable Checklist For a usable minimal harness, leave the target project with: [ ] AGENTS.md or CLAUDE.md [ ] feature list.json [ ] progress.md [ ] init.sh [ ] Optional session handoff.md for multi session work [ ] Documented verification evidence or next action If you cannot create files, provide exact file contents and commands instead.

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