external/skills/agent-development/SKILL.md
Use when the user wants to design Codex agent equivalents (specialized workers/profiles/prompt files), define triggering conditions, or build reusable agent prompts and validation tools.
npx skillsauth add troykelly/codex-skills agent-developmentInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
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Codex CLI does not auto-discover "agent" files the way Claude plugins do. To recreate agent behavior in Codex, combine:
codex-subagent, codex exec, or worker-dispatch) for isolated execution.This skill standardizes an agent card format (YAML frontmatter + prompt body) and shows how to run it with Codex.
Store agent prompts in agents/<agent-name>.md. Frontmatter is metadata for humans and validators; Codex does not read it automatically.
Required fields:
name (kebab-case identifier)description (when to use this agent)Recommended fields:
profile (Codex config profile name)model (override model)sandbox_mode and approval_policy (safety defaults)tools (advisory list of tools; use sandbox/approval to enforce)Example:
---
name: pr-reviewer
description: Use this agent when the user asks for a code review or to audit a pull request.
profile: review-worker
model: gpt-5.2-codex
sandbox_mode: workspace-write
approval_policy: on-request
tools: ["Read", "Grep", "Bash"]
---
You are a senior PR reviewer...
Preferred (subagent runner):
codex-subagent pr-reviewer <<'EOF'
[Provide task context and scope here.]
EOF
Fallback (manual codex exec):
awk 'BEGIN{c=0} /^---$/{c++; next} c>=2 {print}' agents/pr-reviewer.md | codex exec -p review-worker -
Define per-agent profiles in ~/.codex/config.toml:
[profiles.review-worker]
model = "gpt-5.2-codex"
sandbox_mode = "workspace-write"
approval_policy = "on-request"
Profiles capture the model and safety settings that Claude agents used to embed in frontmatter.
To make agent usage automatic, create a skill describing the trigger and invocation. The skill body should instruct how to run the agent card or spawn a worker.
Example trigger entry:
description: Use when the user asks for a PR review or code audit; run the pr-reviewer agent card.
See references/triggering-examples.md.
Use scripts/validate-agent.sh to validate agent cards for required fields and prompt length.
references/system-prompt-design.md for prompt structurereferences/triggering-examples.md for trigger phrasingreferences/agent-creation-system-prompt.md for AI-assisted agent card generationexamples/agent-creation-prompt.md for a complete prompt templateexamples/complete-agent-examples.md for full agent card examplesdata-ai
Defines behavior protocol for spawned worker agents. Injected into worker prompts. Covers startup, progress reporting, exit conditions, and handover preparation.
development
Defines context handover format when workers hit turn limit. Posts structured handover to GitHub issue comments enabling replacement workers to continue seamlessly.
data-ai
Use to spawn isolated worker processes for autonomous issue work. Creates git worktrees, constructs worker prompts, and handles worker lifecycle.
tools
Entry point for ALL work requests - triages scope from trivial to massive, asks clarifying questions, and routes to appropriate planning skills. Use this when receiving any new work request.