agents-brain

Agents Brain

If these instructions are already present in the conversation from a slash or dollar invocation, follow them directly; do not invoke this skill again through a skill tool.

Create or polish repo-local context as one coherent system: human-facing README.md files, agent-facing AGENTS.md files with companion CLAUDE.md symlinks, existing project-installed skills under .agents/skills, eligible source-catalog skills under skills/<name>/, and context docs — any other Markdown files, under any name or directory, whose content is durable guidance for agents or humans, such as conventions, command catalogs, data-format rules, workflow runbooks, and reference material.

Success means every selected target is grounded in repository evidence, respects its audience and scope, spends agent context only on guidance that changes behavior, and passes the narrowest repository-defined validation. Stop after reporting completed or planned changes, validation, and any blockers.

Model and Context Optimization

Optimize skills and other agent-facing context for GPT-5.6 and Claude Fable 5 while preserving README.md as clear human-facing documentation. Before complex, long-running, multi-tool, or orchestration-heavy context work, resolve scripts/fetch-guidance.sh relative to this skill directory, run it once for gpt-5p6 and once for claude-fable-5, and read both returned files completely. The helper retrieves the official GPT-5.6 prompting guidance and Claude Fable 5 prompting guidance because their recommendations may evolve. Simple context work does not require either guide.

Accept an integrity-valid cached guide for 24 hours. Use --refresh for explicitly latest or change-sensitive work, materially disputed guidance, or conflicts with observed model behavior. Interpret helper diagnostics precisely:

• cached reused a guide validated no more than 24 hours ago without network access.
• revalidated refreshed validation metadata after a successful conditional 304 response.
• fetched atomically replaced the cache with integrity-valid content from the pinned official URL.
• stale reused a guide validated no more than seven days ago after live retrieval failed. Proceed only after reading it and disclose the validation timestamp and retrieval failure in the final risks.

Forced refreshes, expired entries, integrity failures, and unexpected redirects fail closed. If either required guide cannot be returned, stop qualifying work before writing instead of substituting memory or another source. Never create the cache in a repository or skill installation.

Keep only content that changes a decision, prevents an evidenced mistake, or supplies a non-discoverable constraint. State each meaning once at the narrowest reliable load scope, except where independently installed artifacts need to stay self-contained. Preserve authority, safety, material exceptions, semantic success criteria, and exact machine-consumed text. Documentation-only authority does not permit changing helpers or schemas; report an extraction opportunity instead.

Choose a Workflow

Choose exactly one workflow and read only its reference.

For skill creation, first inspect applicable repository instructions. When they define a source catalog and lifecycle, stop and follow that repository-owned workflow. Use skill-writing only when no catalog-specific workflow exists.

If the intent is unclear, select polish in --dry-run mode and report the smallest useful planned change set.

Authority

• Explicit create, update, polish, repair, fix, or equivalent intent authorizes in-scope local writes. Inspection-only intent and --dry-run do not.
• Require explicit confirmation before deleting README.md, AGENTS.md, CLAUDE.md, or context-doc targets. --force authorizes documented overwrites, not deletions.
• Treat a broad write request as authorization for the requested scope. Otherwise, preview a change set larger than a handful of files and stop before writing.
• Do not expand from documentation work into source changes, skill creation, or external writes.

Arguments

• path: Optional repo-relative subtree. Restrict documentation, package-root, project-skill, source-catalog skill, and context-doc discovery to that subtree.
• target ...: Optional filters during polish: skill names from existing .agents/skills/<name>/ or eligible skills/<name>/ trees, or repo-relative Markdown paths selecting specific context docs.
• --root-only: Select only root README.md, AGENTS.md, and CLAUDE.md targets. Exclude project-installed skills, source-catalog skills, and context docs unless explicitly selected by target.
• --dry-run: Report planned writes and concise diffs without changing files.
• --preserve: During polish, keep accurate user-authored prose and structure; fix only drift and obvious noise.
• --minimal: Produce the smallest context that still meets the completion bar.
• --thorough / --full: Perform deeper analysis only where it adds durable, repository-specific context.
• --force: During create, regenerate existing README.md or AGENTS.md targets without prompting. Never applies to skills or deletions.

If --minimal and --thorough / --full are both present, make no writes and ask the user to choose. Report unrecognized flags; continue only when they cannot change scope, safety, or write behavior.

Repository Guard Rail

Run before discovery or writes:

cwd="$(pwd -P)"
case "$cwd" in
  /) printf 'abort: refusing to run at the filesystem root\n' >&2; exit 1 ;;
esac
repo_root="$(git rev-parse --show-toplevel 2>/dev/null)" || {
  printf 'abort: not inside a git repository\n' >&2; exit 1; }
managed_skill_root=
case "$repo_root" in
  /|"$HOME") printf 'abort: unsupported repo root: %s\n' "$repo_root" >&2; exit 1 ;;
  "$HOME/.agents"|"$HOME/.codex"|"$HOME/.claude") managed_skill_root="$repo_root/skills" ;;
  "$HOME/.agents/"*|"$HOME/.codex/"*|"$HOME/.claude/"*)
    printf 'abort: repo root is nested under an agent configuration repository: %s\n' "$repo_root" >&2; exit 1 ;;
esac
if [ -n "$managed_skill_root" ]; then
  case "$cwd" in
    "$managed_skill_root"|"$managed_skill_root/"*)
      printf 'abort: installed skills must be edited in their source catalog: %s\n' "$cwd" >&2; exit 1 ;;
  esac
fi

When managed_skill_root is set, allow README.md, AGENTS.md, and CLAUDE.md work elsewhere in that repository, but exclude the entire installed skills/ tree from every workflow. Apply the exclusion before discovery, canonicalization, or symlink traversal. If path, a target, or an explicit request would enter that tree, make no writes there and report that the skill must be edited in its source catalog. --force does not override this boundary.

Outside managed agent-config roots, eligible git-tracked skills/<name>/ source catalogs are in scope for polish per references/polish.md.

Snapshot git status --short before broad edits. Preserve unrelated pre-existing changes and re-check expected paths after generators or broad commands.

Discovery and Tool Routing

Use git-aware discovery, canonicalize every candidate beneath repo_root, and exclude VCS, dependency, environment, and build outputs. Deliberately include ignored .agents/skills/*/SKILL.md only when project skills are selected. Discover git-tracked, non-ignored, non-symlinked skills/*/SKILL.md only outside managed agent-config roots and only when source-catalog skills are selected. Parse each selected skill's YAML frontmatter. Inspect only a project-installed skill's declared write boundary before deciding whether it qualifies for a coordination exemption. Prefer fd, fall back once on suspiciously narrow results, and synthesize independent repository evidence before writing.

Discover context docs by following Markdown links from README.md, AGENTS.md, CLAUDE.md, and SKILL.md files, then by scanning remaining tracked Markdown whose content qualifies. Classify by content, never by file name or location. Exclude changelogs, licenses, legal and policy notices, generated or vendored documentation, and prose that is product content rather than guidance. When classification is uncertain, leave the file out of scope and report it as a candidate.

Completion and Report

After writes, run repository-defined Markdown formatting or checks when present. If skill frontmatter or agents/openai.yaml changed in a project-installed skill, run its invocation metadata check. Verify changed CLAUDE.md symlinks resolve to sibling AGENTS.md. In --dry-run, report commands that would depend on planned files instead of running them.

Lead with ### ✅ Context updated only after writes and required validation pass, ### ⚠️ Context updated — validation failed when files were written but required checks fail, ### 🔎 Context preview — no files written in dry-run mode, or ### ⛔ Context blocked — no files written for a pre-write stop. Then report only:

1. 🧭 Mode and scope: workflow, dry-run status, target counts, and relative paths in a compact table.
2. 📦 Changes: completed or planned changes grouped by directory; use a tree when it makes path ownership clearer.
3. 🧪 Validation: exact commands, result, and any justified skip in a table.
4. ⚠️ Blockers and risks: conflicts, advisories, and unrecognized flags; omit when empty.

Keep paths, commands, guard-rail errors, symlink targets, and user-authored content exact and undecorated. Omit empty detail and stop once the selected targets meet the completion bar.

References

• polish: read references/polish.md.
• create: read references/create-docs.md.