Agent skill

Review Agent Harness

by majiayu000 in majiayu000/spellbook

Review whether a repository's coding-agent harness can reliably carry work from intent through controlled execution, verification, delivery, and learning.

MITAuto-check passedAgent Workflows

Install Review Agent Harness

skills CLI
$ npx skills add majiayu000/spellbook --skill review-agent-harness -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install majiayu000/spellbook review-agent-harness --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/majiayu000/spellbook.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/review-agent-harness .claude/skills/review-agent-harness && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
review-agent-harness
GitHub stars
287
Token cost
~3.5k tokens
SKILL.md length
1,633 words
Files
14 (incl. scripts, references)
Skills in repo
97
Repo updated
First seen
Licence
MIT

At a glance

Review whether a repository's coding-agent harness can reliably carry work from intent through controlled execution, verification, delivery, and learning.

  • Works in 5 steps: Freeze The Evidence Boundary → Run Three Isolated Evidence Passes → Reconcile Findings → …
  • Asked to assess agent readiness
  • SKILL.md covers Route And Scope, Step 1: Freeze The Evidence…, Step 2: Run Three Isolated… and Step 3: Reconcile Findings, plus 6 more sections
  • Runs Python scripts from its folder; calls python3

What it does

Review Agent Harness is an agent skill from majiayu000/spellbook. Review whether a repository's coding-agent harness can reliably carry work from intent through controlled execution, verification, delivery, and learning. Use when asked to assess agent readiness, repeated agent failures, Rules/Skills/Hooks/Memory effectiveness, missing validation or recovery loops, or whether a harness repair improved later outcomes. Do not use for code-only audits, AGENTS-only audits, individual skill reliability reviews, or executing the task itself.

Its SKILL.md is about 3.5k tokens, which your agent loads only when the skill is triggered. The skill folder holds 17 other files, including scripts and reference files (for example `agents/openai.yaml`, `evals/evals.json` and `references/finding-contract.md`).

It sits in Agent Workflows. It works with Git. The repository describes itself as: Cross-runtime skills for Claude Code, Codex, and multi-agent workflows. The licence is MIT.

When your agent uses it

  • Asked to assess agent readiness
  • Repeated agent failures
  • Rules/Skills/Hooks/Memory effectiveness
  • Missing validation

Example prompts

  • “/review-agent-harness”

Requirements

  • Python 3

Workflow steps

5 steps, taken from the step headings in SKILL.md.

  1. Freeze The Evidence Boundary
  2. Run Three Isolated Evidence Passes
  3. Reconcile Findings
  4. Report Or Track History
  5. Repair And Later Effect

What it can do on your machine

Read from SKILL.md and the folder at commit ed52af7. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Ships 6 files in scripts/ (Python), which the agent can run.

    Shell commands in SKILL.md call:

    • python3

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Review Agent Harness loads about 3.5k tokens when it runs, and up to ~8.4k if it reads all its reference files. Until then it costs about 124 tokens; SKILL.md has 1,633 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~124
When it runs · the whole SKILL.md, loaded when a task matches
~3.5k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~8.4k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from majiayu000/spellbook at commit ed52af7, republished under its MIT licence (© majiayu000). 1,633 words, ~3,515 tokens.

Download SKILL.mdSave it as .claude/skills/review-agent-harness/SKILL.md (or your agent's skills folder). This skill also uses 13 other files; get the full folder from GitHub.
name
review-agent-harness
description
Review whether a repository's coding-agent harness can reliably carry work from intent through controlled execution, verification, delivery, and learning. Use when asked to assess agent readiness, repeated agent failures, Rules/Skills/Hooks/Memory effectiveness, missing validation or recovery loops, or whether a harness repair improved later outcomes. Do not use for code-only audits, AGENTS-only audits, individual skill reliability reviews, or executing the task itself.

Review Agent Harness

Review the operating system around coding agents, not only its files. Separate declared assets, reachable routes, observed task use, and later outcomes.

Route And Scope

Resolve the directory containing this SKILL.md before running its scripts. Select one mode:

  • static: inspect the target repository only. Use by default.
  • episode: add explicitly authorized Codex or Claude Code JSONL sources.
  • longitudinal: compare a validated report with the existing ledger.

Default to inline, read-only output. Write a durable report under the target only when the user explicitly requests an artifact or historical tracking. Never discover user-home Sessions, read Memory bodies, or inspect another provider merely because its files are available.

Use adjacent skills instead when their narrower owner is sufficient:

  • codebase-audit for code defects and architecture health;
  • repo-agent-context-audit for AGENTS, Skills, and Specs alone;
  • skill-lifeguard for one Skill's reliable contract;
  • flowguard for running a long task;
  • review-gate before landing an agent-generated diff.

Step 1: Freeze The Evidence Boundary

Record target, mode, provider, locale, decision, acceptance boundary, output mode, included sources, excluded sources, and unavailable evidence. Treat a missing required source as unobserved; do not substitute a broader directory, another provider, or remembered results.

Resolve the target before interpreting assets or assigning scores. The collector classifies it as exact_git_root, inside_git_worktree, contains_nested_git_root, or non_git_directory. If the supplied directory contains a nested Git root, stop and retarget that exact repository; do not score the parent as though it were the project. For a Git target, the collector uses Git's tracked and untracked inventory and excludes ignored worktrees and prior review output from repository evidence.

Run static collection from the installed Skill directory:

bash
python3 scripts/collect_evidence.py \
  --target /absolute/target \
  --mode static \
  --locale zh-CN \
  --decision "assess agent-harness readiness" \
  --acceptance-boundary "resolve all five dimensions" \
  --output-mode inline \
  --output /temporary/evidence.json

For Session-informed review, require the user to authorize exact files or an exact root. Use one provider per evidence envelope:

bash
python3 scripts/collect_evidence.py \
  --target /absolute/target \
  --mode episode \
  --provider codex \
  --session-file /explicit/session.jsonl \
  --locale zh-CN \
  --decision "explain the observed verification gap" \
  --acceptance-boundary "separate configured and exercised routes" \
  --output-mode inline \
  --output /temporary/evidence.json

Use --session-root only when that exact recursive scope was authorized. Add --include-request-summaries only when sanitized request summaries are needed for the decision. Read Privacy Boundary and Session Adapters before Session-informed work.

Omit --output to stream evidence to stdout. Inline means no target writes; environment-owned scratch remains allowed. validate_findings.py --input - accepts findings JSON from stdin when the caller already has a stream.

Checkpoint: collection must return agent-harness-evidence; every stage must be available, constrained, not_authorized, not_applicable, unavailable, or unobserved. A depth-limited scan is constrained, never silently complete. Stop on malformed output or an unexplained missing stage.

Copy the collector-owned scope.target_id and complete scope.snapshot (baseline, target_relation, and id) into the findings document. Never author these values manually. The renderer and ledger updater recompute the binding from --target and reject a different local directory or any target state that changed after collection. A previous report, ledger row, branch name, or remembered result is a historical lead only. Recheck any retained claim against the frozen current snapshot and label genuinely historical evidence as such.

Step 2: Run Three Isolated Evidence Passes

Keep the passes logically independent even when one agent runs them in sequence:

  1. Task pass: use the current goal, corrections, acceptance boundary, and authorized Episode facts. Do not infer repository mechanisms.
  2. Project pass: use static startup, commands, tests, CI, Git, delivery, and recovery evidence. Do not infer Session behavior.
  3. Agent-assets pass: use project Rules, Skills, Hooks, settings, and other configured surfaces. Presence and counts are navigation facts only.

Do not launch parallel agents by default. If the user explicitly requests threads, use threads with read-only lanes and bounded evidence packets. A specialist proposes candidates; it does not assign final severity or claim effectiveness.

Read Review Model before classifying the five dimensions. Use present -> reachable -> exercised -> outcome_supported only when each stronger state has direct evidence.

Resolve all 15 stable checks, three per dimension. Assign a score to each dimension only after resolving its checks. The score is an evidence-bounded summary, not a finding: present caps a dimension at 74, reachable at 84, exercised at 94, and outcome_supported at 100; missing or unobserved caps it at 59. Use the lowest applicable check ceiling and retain a short score rationale. Do not compute an overall score.

Step 3: Reconcile Findings

Retain each distinct eligible candidate. Merge only when consequence, root cause, owner, and verifier are the same. The lead alone assigns severity, confidence, primary dimension, verification state, and priority.

Read Finding Contract. Every finding needs:

  • an observed consequence or exact governing requirement;
  • a bounded evidence reference;
  • a cause chain and smallest owner;
  • an executable repair route;
  • a machine-checkable verifier.

Counts, file absence without a requirement, similarity, theoretical risk, score, or unavailable evidence never create a finding. Critical and High findings require an adversarial check; retain an unavailable check as unverified instead of presenting it as confirmed.

Record each executed verifier in verification_runs with a stable id, purpose, result, exit code, final-state flag, and bounded summary. A confirmed Critical or High finding must cite a final-state candidate_refutation or targeted_reproduction run that supports the claim. Inspect aggregate exit semantics: a child syntax error or failed subcheck paired with aggregate exit 0 is evidence of a false-green verifier, not a passing check.

Author one agent-harness-findings JSON object in environment-owned scratch space, then validate it:

bash
python3 scripts/validate_findings.py --input /temporary/findings.json --strict --json

Fix the findings data, not the validator. Stop if validation does not pass.

Step 4: Report Or Track History

For inline review, render the overview, frozen snapshot, five-dimension scorecard, all 15 checks, structured verification runs, findings, evidence boundary, and at most three priority moves in the response. Do not write to the target.

When durable output is explicitly requested, render atomically:

bash
python3 scripts/render_report.py \
  --findings /temporary/findings.json \
  --evidence /temporary/evidence.json \
  --target /absolute/target \
  --out /absolute/target/.agent-harness-review \
  --json

The renderer refuses to replace an existing run and writes only validated findings.json, privacy-safe evidence.json, and derived report.md.

For longitudinal mode, update the ledger after a fresh review:

bash
python3 scripts/update_ledger.py \
  --findings /temporary/findings.json \
  --target /absolute/target \
  --ledger /absolute/target/.agent-harness-review/ledger.json \
  --json

An absent prior finding remains open with recheck_required until a targeted spot-check produces an agent-harness-resolution-confirmations document. Each confirmation must retain the finding id, verifier, and one bounded evidence_ref. Pass it with --resolution-confirmations /temporary/confirmations.json. Never resolve from finder absence or an id-only assertion.

Show full SKILL.md (667 more words)Show less

Step 5: Repair And Later Effect

Read Repair Loop for follow-up. This review does not authorize fixes. Route a selected finding to its owner in a separate task, run its verifier on the final state, and update repair_state only.

Do not upgrade learning-retention from same-window repair evidence. For a tool-backed route, collect the later Episode with --mechanism-category edit or validation, --episode-role later, and an explicit --comparison-basis; collect the baseline with the same basis and --episode-role baseline. The adapter count shows only that coarse mechanism was exercised. Use bounded file or policy evidence to map the category to the repaired route. Separately require target-owned command or artifact references showing the result improved and guardrails still passed. Adapter counts, collection time, or a request summary alone never prove later effect.

When claiming outcome_supported, pass both collector envelopes to every gate: validate_findings.py --evidence baseline.json --evidence later.json, and use the same repeated --evidence flags with render_report.py or update_ledger.py. The claim is rejected without exactly one bound baseline and one bound later envelope.

Operating Contract

Direct actions:

  • inspect the authorized repository read-only;
  • run bounded local collectors and validators;
  • produce inline findings;
  • write report artifacts only when durable output was requested.

Escalate before:

  • reading stored Sessions, Memory bodies, or user-home assets outside an exact authorization;
  • editing Rules, Skills, Hooks, settings, source, tests, or generated files;
  • installing automation, publishing, committing, pushing, or changing remote state.

Evidence-backed pushback: reject a requested score or conclusion when the target is not the exact repository, the relevant evidence is unavailable, an aggregate verifier hides a failed subcheck, or a historical claim was not rechecked on the frozen snapshot. State the concrete boundary and the smallest next command that could resolve it.

Feedback loop: replay the closest case in evals/evals.json after a miss or false positive, add one focused regression test, and patch the smallest durable owner in the collector, validator, renderer, or written contract.

Negative Examples And Gotchas

  • Do not turn “five Skills installed” into “Skills are effective.” Require task-linked use and a result.
  • Do not turn “no Session access” into “no failures.” Mark behavior unobserved and continue only with static mechanisms.
  • Do not treat a test run before the final edit as verification closure. Run the mapped check on the final state.
  • Do not mark a missing previous finding resolved because a finder omitted it. Spot-check and confirm the id.
  • Do not copy raw prompts, commands, paths, secrets, or stable Session ids into findings or reports. Keep only adapter-produced facts.
  • Do not use a numeric score as evidence or average the dimensions into an overall score. Scores summarize the 15 evidence-bounded checks only.
  • Do not inherit a finding from an older report. Treat it as a lead and rerun its mapped check on the frozen snapshot.
  • Do not redirect durable output to a sibling directory. The renderer accepts only /absolute/target/.agent-harness-review, and the ledger updater accepts only its ledger.json below that directory.
  • Do not attribute a generated or aggregate failure to the nearest file. Trace the caller, configuration, and output owner before choosing the smallest repair owner.

Done When And Drift Loop

Finish only when:

  • all five dimensions appear exactly once with evidence or an explicit unobserved / not_applicable boundary;
  • all 15 stable checks appear exactly once and each dimension score stays below its weakest applicable evidence ceiling;
  • every finding passes validate_findings.py --strict;
  • durable reports, when requested, are renderer-produced and paths are exact;
  • unavailable stages and unverified high-severity candidates remain visible;
  • no target mutation occurred outside explicit authority.

Use evals/evals.json and the repository tests as the replay surface. Patch the smallest durable owner when the Skill over-triggers, misses a primary request, accepts private data, treats configuration as use, resolves from absence, or claims later effectiveness from same-window checks.

Resources

  • scripts/collect_evidence.py: static collector and Session adapter facade.
  • scripts/validate_findings.py: findings, evidence-state, and privacy gate.
  • scripts/render_report.py: atomic durable Markdown renderer.
  • scripts/update_ledger.py: conservative longitudinal ledger.
  • references/review-model.md: dimensions and evidence semantics.
  • references/finding-contract.md: authoring and reconciliation contract.
  • references/privacy-boundary.md: authorization and redaction rules.
  • references/session-adapters.md: Codex and Claude Code input boundaries.
  • references/repair-loop.md: repair progress versus later effectiveness.

© majiayu000, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 13 other files (scripts, references) in skills/review-agent-harness of majiayu000/spellbook.

  • SKILL.md
  • agents/openai.yaml
  • evals/evals.json
  • references/finding-contract.md
  • references/privacy-boundary.md
  • references/repair-loop.md
  • references/review-model.md
  • references/session-adapters.md
  • scripts/collect_evidence.py
  • scripts/harness_common.py
  • scripts/render_report.py
  • scripts/session_adapters.py
  • scripts/update_ledger.py
  • scripts/validate_findings.py

Open the folder on GitHubat commit ed52af7

Compare with similar skills

Review Agent Harness next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Review Agent Harness compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Review Agent Harness this skillmajiayu000/spellbook287—~3.5kAutomated safety check: PassMIT
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CodeGraph Agent Evalcolbymchenry/codegraph74k—~950Automated safety check: PassMIT
Neat-Freak Knowledge CloseoutKKKKhazix/khazix-skills21k—~1.9kAutomated safety check: PassMIT
O2 Review Loopopenobserve/openobserve22k—~3.7kAutomated safety check: PassAGPL-3.0
Beads Task Memorygastownhall/beads28k—~1.2kAutomated safety check: PassMIT

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Works with

Categories

Questions about Review Agent Harness

What does Review Agent Harness do?

Review whether a repository's coding-agent harness can reliably carry work from intent through controlled execution, verification, delivery, and learning. Review Agent Harness is an agent skill from majiayu000/spellbook. Review whether a repository's coding-agent harness can reliably carry work from intent through controlled execution, verification, delivery, and learning.

When should I use Review Agent Harness?

Review Agent Harness fits situations like: asked to assess agent readiness; repeated agent failures; rules/Skills/Hooks/Memory effectiveness; missing validation.

How do I install Review Agent Harness in Claude Code?

Run `npx skills add majiayu000/spellbook --skill review-agent-harness -a claude-code`. Or copy the skill folder (skills/review-agent-harness in majiayu000/spellbook) into .claude/skills/review-agent-harness in your project. Claude Code loads it when a task matches its description.

How do I install Review Agent Harness in Codex?

Run `npx skills add majiayu000/spellbook --skill review-agent-harness -a codex`. Or copy the skill folder (skills/review-agent-harness in majiayu000/spellbook) into .agents/skills/review-agent-harness in your project. Codex loads it when a task matches its description.

Can I use Review Agent Harness in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add majiayu000/spellbook --skill review-agent-harness -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/review-agent-harness, .gemini/skills/review-agent-harness, .github/skills/review-agent-harness and .opencode/skills/review-agent-harness in your project.

What does Review Agent Harness need to run?

Going by SKILL.md and its folder, Review Agent Harness needs Python for the scripts in its folder and the command-line tools its instructions call (python3). Our summary lists: Python 3.

Does Review Agent Harness access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Review Agent Harness safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.

What licence does Review Agent Harness use?

Review Agent Harness is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Review Agent Harness use?

About 3.5k tokens (SKILL.md is roughly 14k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 4.9k tokens, read only when the agent opens those files.

What are the alternatives to Review Agent Harness?

Skills that share tags, products or a category with Review Agent Harness: Darwin Skill Optimizer (alchaincyf/darwin-skill, 6.2k stars), CodeGraph Agent Eval (colbymchenry/codegraph, 74k stars), Neat-Freak Knowledge Closeout (KKKKhazix/khazix-skills, 21k stars) and O2 Review Loop (openobserve/openobserve, 22k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Review Agent Harness?

majiayu000 (a GitHub user) maintains it in majiayu000/spellbook, which has 287 GitHub stars. The repository holds 97 skills in this directory. The repository was last updated on October 8, 2026.

Source: majiayu000/spellbook on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.