Claude Code Agent Development
anthropics/claude-plugins-official
Explains how to write agents for Claude Code plugins: the markdown file with YAML frontmatter, trigger descriptions, model and color settings, and system prompt design.
Rewrite Spectre subagent definitions into compact, contract-driven agents with clear routing, least-privilege tools, output schemas, and an auditable rewrite trail.
$ npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install joenandez/spectre spectre-rewrite-subagent --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/joenandez/spectre.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/spectre-rewrite-subagent .claude/skills/spectre-rewrite-subagent && rm -rf skills-srcUse ~/.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/
Install the "spectre-rewrite-subagent" agent skill from https://github.com/joenandez/spectre/tree/main/.agents/skills/spectre-rewrite-subagent into .claude/skills/spectre-rewrite-subagent/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "spectre-rewrite-subagent", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/joenandez/spectre/tree/main/.agents/skills/spectre-rewrite-subagentType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install joenandez/spectre spectre-rewrite-subagent --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/joenandez/spectre.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/spectre-rewrite-subagent .agents/skills/spectre-rewrite-subagent && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "spectre-rewrite-subagent" agent skill from https://github.com/joenandez/spectre/tree/main/.agents/skills/spectre-rewrite-subagent into .agents/skills/spectre-rewrite-subagent/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "spectre-rewrite-subagent", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install joenandez/spectre spectre-rewrite-subagent --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/joenandez/spectre.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/spectre-rewrite-subagent .cursor/skills/spectre-rewrite-subagent && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "spectre-rewrite-subagent" agent skill from https://github.com/joenandez/spectre/tree/main/.agents/skills/spectre-rewrite-subagent into .cursor/skills/spectre-rewrite-subagent/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "spectre-rewrite-subagent", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/joenandez/spectre.git --path .agents/skills/spectre-rewrite-subagent--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install joenandez/spectre spectre-rewrite-subagent --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/joenandez/spectre.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/spectre-rewrite-subagent .gemini/skills/spectre-rewrite-subagent && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "spectre-rewrite-subagent" agent skill from https://github.com/joenandez/spectre/tree/main/.agents/skills/spectre-rewrite-subagent into .gemini/skills/spectre-rewrite-subagent/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "spectre-rewrite-subagent", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install joenandez/spectre spectre-rewrite-subagentInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/joenandez/spectre.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/spectre-rewrite-subagent .github/skills/spectre-rewrite-subagent && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "spectre-rewrite-subagent" agent skill from https://github.com/joenandez/spectre/tree/main/.agents/skills/spectre-rewrite-subagent into .github/skills/spectre-rewrite-subagent/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "spectre-rewrite-subagent", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install joenandez/spectre spectre-rewrite-subagent --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/joenandez/spectre.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/spectre-rewrite-subagent .opencode/skills/spectre-rewrite-subagent && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "spectre-rewrite-subagent" agent skill from https://github.com/joenandez/spectre/tree/main/.agents/skills/spectre-rewrite-subagent into .opencode/skills/spectre-rewrite-subagent/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "spectre-rewrite-subagent", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
spectre-rewrite-subagentRewrite Spectre subagent definitions into compact, contract-driven agents with clear routing, least-privilege tools, output schemas, and an auditable rewrite trail.
Spectre Rewrite Subagent is an agent skill from joenandez/spectre. Rewrite Spectre subagent definitions into compact, contract-driven agents with clear routing, least-privilege tools, output schemas, and an auditable rewrite trail. Use when reviewing or rewriting plugins/spectre/agents/.md, when the user asks to improve subagents/agent definitions, or when checking generated plugins/spectre-codex/agents/.toml. Do not use for rewriting workflow skills; use spectre-rewrite-skill for SKILL.md compression.
Its SKILL.md is about 1.8k tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files (for example `agents/openai.yaml`).
It sits in Agent Workflows, covering Subagents. The repository describes itself as: Spectre is a battle-tested 6 stage agentic engineering workflow for building complex, production-ready features. You stay in the loop for the decisions that matter. Your agents…. The licence is MIT.
6 steps, taken from the step headings in SKILL.md.
Read from SKILL.md and the folder at commit 931c9e8. It shows what the files ask for, not the result of running them.
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.
Shell commands in SKILL.md call:
npmFrom the folder's file list and the shell code blocks in SKILL.md.
No URLs in SKILL.md. Its commands use npm, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Spectre Rewrite Subagent loads about 1.8k tokens when it runs. Until then it costs about 119 tokens; SKILL.md has 740 words of instructions outside code blocks.
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.
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); files beside SKILL.md are not scanned.
The full file from joenandez/spectre at commit 931c9e8, republished under its MIT licence (© joenandez). 740 words, ~1,786 tokens.
.claude/skills/spectre-rewrite-subagent/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.Rewrite one or more Spectre subagent definitions from broad persona prompts into focused worker contracts. Produce a reviewable proposal by default; apply changes to the live plugin only when the user explicitly asks.
$ARGUMENTS (finder, analyst, patterns, reviewer, tester, dev, web-research) or explicit file paths.plugins/spectre/agents/<agent>.md.plugins/spectre-codex/agents/<agent>.toml.proposal by default: write review artifacts only.apply only if the user explicitly asks to update live definitions.Assume cwd is the Spectre repo root. If no target is provided, ask which subagent to rewrite.
Read these before drafting:
docs/tasks/main/research/subagent_definition_best_practices_053126.md - subagent best practices and practitioner findings.scripts/translators/agents.cjs only when applying or checking Codex TOML generation.docs/spectre-design-research.md only if deciding whether a block is load-bearing or generic bloat.Source of truth is plugins/spectre/agents/*.md; generated TOML is derived output.
Record:
name, description, tools, codex_sandbox_mode, model, and body line/token size.name, description, sandbox_mode, and developer_instructions if present.Choose one primary role and make the rewrite fit it:
locator: finds files/areas; returns grouped paths only.analyst: explains how code works; returns cited implementation facts.pattern-miner: finds reusable examples; returns 2-5 examples and recommendation.reviewer: identifies risks/findings; returns severity-ranked findings first.tester: writes or verifies tests; decide whether it is write-capable or read-only.implementer: writes code; may edit files and run commands.web-briefer: verifies current/third-party facts; returns sourced findings.If a source agent mixes roles, flag the split decision instead of silently broadening it.
Walk the source top to bottom. For each block, assign one verdict:
KEEP: changes behavior measurably.CUT: persona filler, generic expertise, tutorials, marketing, jokes, or capability catalogs the model already knows.CONTRACT: restate as mission, inputs, boundaries, method, or return contract.PERMISSION: move to tools/sandbox/model decision.REFERENCE: preserve only by linking to an existing reference doc.Keep specifics that define behavior: routing triggers, scope boundaries, least-privilege tools, citations, exact output schema, empty-result behavior, verification commands, artifact paths, and "do not write" constraints.
Use this shape unless the existing agent has a stronger local convention:
---
name: <agent>
description: <one or two sentences: trigger, boundary, return type>
tools: <least-privilege tool list>
codex_sandbox_mode: <read-only|workspace-write>
model: <model if intentionally set>
---
You are a focused <role>. <One sentence mission.>
## Mission
<What this agent produces, not a broad capability list.>
## Inputs Expected
- <files/diff/range/task/error/source constraints expected from parent>
## Boundaries
- <what to do>
- <what not to do, especially write/no-write and no nested delegation>
## Method
- <only role-specific heuristics and failure-mode guards>
## Return Contract
<compact schema; include citations, uncertainty, empty-result behavior, and max summary size if useful>Description rules:
Tool rules:
Read, Grep, Glob, LS and codex_sandbox_mode: read-only.Return rules:
file:line for code claims.In proposal mode, write one artifact per agent:
docs/tasks/spectre-light/proposals/agents/<agent>.rewrite.md
Create the directory if needed. The artifact must contain:
# Subagent Rewrite Proposal: <agent>## Inventory## Role Classification## Block Triage with | source block | verdict | reason |## Permission Decision## Proposed Agent Definition as a fenced Markdown block## Stripped Block Ledger with | stripped block | this prevented/claimed | replacement |## Load-Bearing Coverage with | item | where it lives now |## Self-Check## Open QuestionsDo not overwrite live agent files in proposal mode.
When applying:
plugins/spectre/agents/<agent>.md source files.npm run sync-codex.npm run sync-codex -- --check --quiet.plugins/spectre-codex/agents/*.toml except to inspect diffs.For each rewritten agent, report pass/fail:
Write, Edit, or Bash, and use codex_sandbox_mode: read-only.Return:
© joenandez, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
SKILL.md and 1 other file in .agents/skills/spectre-rewrite-subagent of joenandez/spectre.
Open the folder on GitHubat commit 931c9e8
Spectre Rewrite Subagent 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.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Spectre Rewrite Subagent this skilljoenandez/spectre | 164 | — | ~1.8k | Automated safety check: Pass | MIT | |
| Claude Code Agent Developmentanthropics/claude-plugins-official | 38k | 7 repos | ~2.8k | Automated safety check: Pass | Apache-2.0 | |
| Subagent Driven DevelopmentAsvarox/allkaraoke | 261 | 37 repos | ~1.2k | Automated safety check: Pass | None | |
| Dispatching Parallel Agentsultralisp/ultralisp | 258 | 40 repos | ~1.5k | Automated safety check: Pass | None | |
| Paseo Advisor Second Opiniongetpaseo/paseo | 20k | 1 repos | ~756 | Automated safety check: Pass | Custom licence | |
| Task Observerrebelytics/one-skill-to-rule-them-all | 3.2k | 1 repos | ~11k | Automated safety check: Pass | CC-BY-4.0 |
anthropics/claude-plugins-official
Explains how to write agents for Claude Code plugins: the markdown file with YAML frontmatter, trigger descriptions, model and color settings, and system prompt design.
Asvarox/allkaraoke
A skill your agent uses when executing implementation plans with independent tasks in the current session
ultralisp/ultralisp
A skill your agent uses when facing 2+ independent tasks that can be worked on without shared state or sequential dependencies
getpaseo/paseo
Launches one separate agent through Paseo to give a second opinion on the current task, with a self-contained briefing and no permission to edit files.
rebelytics/one-skill-to-rule-them-all
Monitors task execution for skill improvement opportunities.
openobserve/openobserve
Splits a change into planner, coder and independent reviewer roles: you confirm a spec, a subagent implements it, and a separate reviewer checks each round's local WIP commit.
joenandez/spectre
A skill your agent uses when validating that the Spectre plugin itself still works after ANY change to this repo — skills, prompts, agents, hooks, the CLI, the Codex mirror, or a release.
joenandez/spectre
A skill your agent uses when modifying the Codex SPECTRE install flow, SessionStart continuity, project skill syncing, registry injection, or Codex-specific runtime files.
joenandez/spectre
Save a quiet, branch-keyed session snapshot with continuity, active work, and optional task/todo state for automatic resume.
joenandez/spectre
User-invoked front door for durable capture. An agent skill from joenandez/spectre.
joenandez/spectre
Rewrite a verbose SPECTRE skill into a compact, contract-form Spectre skill proposal — clear on WHAT, silent on HOW — grounded in the spectre-light distillation and freedom-tier budget.
joenandez/spectre
Capture durable project decisions, accepted corrections, verified reusable patterns or gotchas, disproved guidance, and changed persistent blockers as soon as they matter.
Categories
Rewrite Spectre subagent definitions into compact, contract-driven agents with clear routing, least-privilege tools, output schemas, and an auditable rewrite trail. Spectre Rewrite Subagent is an agent skill from joenandez/spectre. Rewrite Spectre subagent definitions into compact, contract-driven agents with clear routing, least-privilege tools, output schemas, and an auditable rewrite trail.
Spectre Rewrite Subagent fits situations like: rewriting plugins/spectre/agents/.md; the user asks to improve subagents/agent definitions; checking generated plugins/spectre-codex/agents/.toml; rewriting workflow skills.
Run `npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a claude-code`. Or copy the skill folder (.agents/skills/spectre-rewrite-subagent in joenandez/spectre) into .claude/skills/spectre-rewrite-subagent in your project. Claude Code loads it when a task matches its description.
Run `npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a codex`. Or copy the skill folder (.agents/skills/spectre-rewrite-subagent in joenandez/spectre) into .agents/skills/spectre-rewrite-subagent in your project. Codex loads it when a task matches its description.
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add joenandez/spectre --skill spectre-rewrite-subagent -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/spectre-rewrite-subagent, .gemini/skills/spectre-rewrite-subagent, .github/skills/spectre-rewrite-subagent and .opencode/skills/spectre-rewrite-subagent in your project.
Going by SKILL.md and its folder, Spectre Rewrite Subagent needs the command-line tools its instructions call (npm).
SKILL.md contains no URLs. Its commands use npm, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
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. Review the folder before installing.
Spectre Rewrite Subagent is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
About 1.8k tokens (SKILL.md is roughly 7.1k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
Skills that share tags, products or a category with Spectre Rewrite Subagent: Claude Code Agent Development (anthropics/claude-plugins-official, 38k stars), Subagent Driven Development (Asvarox/allkaraoke, 261 stars), Dispatching Parallel Agents (ultralisp/ultralisp, 258 stars) and Paseo Advisor Second Opinion (getpaseo/paseo, 20k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
joenandez (a GitHub user) maintains it in joenandez/spectre, which has 164 GitHub stars. The repository holds 26 skills in this directory. The repository was last updated on October 2, 2026.
Source: joenandez/spectre on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.