About
The skill-improver autonomously runs a review-and-fix loop on a Claude Code skill using the skill-reviewer agent, continuing until no critical issues remain. It tracks findings across rounds, escalates if fixes stop converging, and includes a scope guard to maintain focus. Use it for iterative skill refinement or to fix quality issues, not for one-time reviews.
Quick Install
Claude Code
Recommendednpx skills add trailofbits/skills -a claude-code/plugin add https://github.com/trailofbits/skillsgit clone https://github.com/trailofbits/skills.git ~/.claude/skills/skill-improverCopy and paste this command in Claude Code to install this skill
Documentation
Skill Improver
Improve a Claude Code skill by running /code-improver:improve — a dynamic workflow
that loops a reviewer and a fixer subagent until a review reports zero critical/major
findings, then strips its own residue. This entry point wires the loop to the
plugin-dev:skill-reviewer agent, so the plugin-dev plugin must be installed
(marketplace claude-plugins-official). The loop, its ledger, and its guards live in
the workflow; this skill resolves the target and relays the outcome.
Starting the loop
The user provided: $ARGUMENTS (if empty, take the target skill from the conversation).
1. Resolve the skill path
- If the input ends with
/SKILL.mdand the file exists, use its directory - If the input is a directory containing
SKILL.md, use that path - Otherwise
Glob(pattern="**/SKILL.md")and filter by skill name or path substring:- Multiple matches: ask the user to choose
- No matches: report the available skills
- Single match: proceed
2. Resolve the loop script
The loop is the dynamic workflow workflows/improve.js in this plugin. Launch it by
path: scriptPath takes a resolved absolute path, and the Workflow tool's name resolves
built-in and project workflows, so a marketplace-installed one may not answer to
code-improver:improve. Try in order, first hit wins — the home directories come before
. so an installed copy beats a checkout of this marketplace:
Bash: ls -d -- "${CLAUDE_PLUGIN_ROOT}/workflows/improve.js"Bash: ls -d -- "${CODEX_PLUGIN_ROOT}/workflows/improve.js"(if that variable is set instead)Bash: find ~/.claude ~/.codex . -maxdepth 7 -path '*/code-improver/workflows/improve.js' -print -quit 2>/dev/null
Use the path exactly as printed. Its plugin directory — the path with
/workflows/improve.js removed — is pluginRoot. If all three come back empty, try
{name: "code-improver:improve"} once; if that is unavailable too, stop and say the loop
could not be located. Do not assemble a path by hand and do not improvise the loop.
3. Invoke the workflow
Run it with the Workflow tool, {scriptPath: "<the path from step 2>", args: {...}}:
{
"target": "<resolved absolute path>",
"reviewer": {
"kind": "agent",
"name": "plugin-dev:skill-reviewer",
"notes": "The target is a Claude Code skill directory; review it as a skill (frontmatter, triggering description, progressive disclosure, referenced files)."
},
"pluginRoot": "<the plugin directory from step 2>",
"maxRounds": 5
}
maxRoundsonly if the user asked for a different cap (--max-rounds N).pluginRootlets the run find its metrics collector; omit the key only if step 2 fell through to the workflow name — the workflow then searches for itself.scope(repo-relative globs) only if the user restricted or widened what the loop may touch; by default the workflow scopes to the skill's plugin directory.decisiononly on continuation (below).
The workflow runs in the background and needs no babysitting: it reviews, fixes, re-reviews, checks scope after every fix round, and can only complete on a clean review. It never commits; all changes stay in the working tree.
If the Workflow tool is unavailable or denied, stop and say so. Do not improvise the loop inline with direct edits — the ledger, scope guard, and escalation guarantees live in the workflow, and an inline imitation has none of them (observed failure: an inline fallback "fixed" a finding by weakening the documented guarantee, exactly what the loop exists to prevent).
If the result is halted: "reviewer-unavailable", relay it and stop. The reviewer
this skill names is not installed; tell the user to install the plugin-dev plugin from
the claude-plugins-official marketplace and re-run. Do not review the skill yourself.
Do not end your turn while the loop is running. The Workflow tool returns a task id immediately; the result comes later. In an interactive session the completion notification re-invokes you — wait for it. In a non-interactive run (scripted, CI, eval) there is no later turn: stopping abandons the loop mid-round, so after launching, poll the task (TaskOutput with the returned task id, or sleep-and-recheck) until it completes, then relay the result. A session that answers "the loop is running, I'll report later" has lost the run.
Relaying the result
The workflow returns a structured result. Report it honestly — the distinctions matter:
converged: true— the last action was a review with zero critical/major findings. Report rounds used, remaining minor findings (open_minor_count), and the artifact paths (ledger_path,metrics).capped: true— the fix budget ran out and the FINAL review still found blocking issues. Say plainly: capped, NOT converged, and listopen_blocking. Do not present this as success.escalation— the loop detected it was not converging (recurring findings, non-decreasing counts, or a fix relocating a problem). Relay the escalation message and finding ids to the user: this needs a design decision, not more rounds.halted— a guard fired (scope violation, unregistered new files, a dead or unavailable reviewer, or a finalize pass whose own edits failed the check that follows it). Relay the paths inviolations/new_untracked_files, the sites infinalize_regressions, and the notes.notesalways travel with the result — surface them; they include loud warnings such as "a git repository was initialized".
Continuing after an escalation
The loop stops on escalation by design. When the user decides (e.g. "keep the blocklist
and document the limitation"), start a fresh run with the same target plus:
{ "decision": "<the user's ruling, verbatim>" }
The new run reloads the on-disk ledger, so every finding, rejection, and verdict carries over — rounds restart, re-derivation does not.
To stop a running loop, stop the workflow task (TaskStop); the ledger on disk is current to the last round and a re-run resumes from it.
What the loop enforces (so you do not have to)
- Fix verification — the next review verifies every fix; fixes to executable behavior carry pins that fail against the pre-fix code.
- Scope — a mechanical git-diff check after every fix round, and after the finalize pass, halts on any out-of-scope change; out-of-scope files git does not track are guarded by content hash, since no diff would show them; completion also requires no unregistered new files in scope.
- Report everything — reviewers report all findings with severity; filtering happens once, at the ledger verdict, and rejections are not re-litigated without new evidence.
- Finalize — before completion the loop strips narration comments, collapses version
churn to exactly one bump (in
plugin.jsonand the marketplace entry that repeats it), and runs a docs-match-code pass. Those edits land after the last review, so a check reads them: an over-eager narration strip or a false docs claim halts withfinalize-regressioninstead of passing as done.
When NOT to use
- One-time review: dispatch the
plugin-dev:skill-revieweragent directly - Quick single fixes: edit the file directly
- Non-skill targets: use the
code-improverskill with a reviewer that fits the target, orpr-improverfor a branch - Exploratory drafting: manual iteration gives more control while the shape is fluid
GitHub Repository
Frequently asked questions
What is the skill-improver skill?
skill-improver is a Claude Skill by trailofbits. Skills package instructions and resources that Claude loads on demand, so Claude can perform skill-improver-related tasks without extra prompting.
How do I install skill-improver?
Use the install commands on this page: add skill-improver to Claude Code as a plugin, or clone its repository into your skills directory, then restart Claude so it picks up the skill.
What category does skill-improver belong to?
skill-improver is in the Meta category.
Is skill-improver free to use?
Yes. skill-improver is listed on AIMCP and free to install.
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