a0-development

name	a0-development
description	Development guide for extending Agent Zero from current source and DOX. Use for framework architecture, tools, extensions, API/WebUI handlers, agent profiles, prompts, skills, projects, runtime boundaries, and contribution workflow. Load the focused reference files before giving implementation guidance.
version	1.1.0
author	Agent Zero Team
tags	["development","framework","agent-zero","extending","tools","extensions","skills","api","agents","prompts","dox"]
trigger_patterns	["extend agent zero","agent zero development","build agent zero feature","create agent zero tool","add extension","framework development","agent zero architecture","how does agent zero work","create agent zero extension","add api endpoint","create agent profile","agent zero internals","how does the agent loop work","extension hook points","prompt system","agent profile","dox"]

Agent Zero Development

Use this skill as the entry point for Agent Zero framework development. It is intentionally lean: load only the reference files that match the task, then verify against the current repository before changing code.

Reality Rules

1. Source and nearest DOX beat memory, examples, and this skill if they disagree.
2. Before editing, read the applicable AGENTS.md chain from the repo root to every file you expect to touch.
3. New capabilities should usually be plugins. For plugin-specific work, load a0-plugin-router and follow the routed specialist skill.
4. Do not assume ports. Discover WebUI host/port from startup output, launcher or Docker mapping, or explicit --host, --port, WEB_UI_HOST, and WEB_UI_PORT configuration.
5. In Docker, framework checks belong to /opt/venv-a0 and agent/user code execution belongs to /opt/venv. Do not use one runtime as proof for the other.
6. Treat /a0/ as the runtime framework root inside Docker. In local development it means the repository root. If a live container matters, prove that /a0 matches the checkout before trusting source-only conclusions.
7. Do not document or change ignored usr/ or tmp/ runtime state unless the user explicitly asks.

Reference Map

Load references with:

{"tool_name": "skills_tool:read_file", "tool_args": {"skill_name": "a0-development", "file_path": "references/<file>.md"}}

Need	Read
Runtime split, root layout, discovery order, path and port boundaries	references/architecture-runtime.md
DOX edit workflow, when to update docs, file-level DOX checks	references/dox-workflow.md
Tool contracts, locations, prompts, and verification	references/tools.md
Python/WebUI extension discovery, hook points, ordering, implicit hooks	references/extensions.md
HTTP API, WebSocket handlers, WebUI extension surfaces	references/api-webui.md
Agent profiles, prompts, skills, projects	references/agents-prompts-skills-projects.md
Plugin-first workflow, where to put new work, handoffs to plugin skills	references/plugins-workflow.md

Working Flow

1. Classify the request: tool, extension, API/WebUI, profile, prompt, skill, project, plugin, runtime, or docs.
2. Read the root AGENTS.md, then the nearest child AGENTS.md files for the target paths.
3. Read the focused reference file from this skill.
4. Inspect the current source files named by the reference before making a claim or patch.
5. Keep changes narrow and in the repo-owned surface. Prefer usr/ for user-created runtime content, but do not document ignored user state unless requested.
6. Update DOX when a durable contract, path, behavior, workflow, responsibility, or verification rule changes.
7. Run targeted checks from the relevant DOX file. For skill-only changes, at minimum verify frontmatter parsing, reference paths, and markdown sanity.

Handoffs

• Plugin creation: load a0-create-plugin.
• Plugin management or installation: load a0-manage-plugin.
• Plugin debugging: load a0-debug-plugin.
• Plugin review or publishing: load a0-review-plugin or a0-contribute-plugin.
• Agent profile creation: load a0-create-agent.
• Skill creation or skill format work: load build-skill.

Closeout

Report the exact files changed, the grounding checks used, whether DOX was updated or intentionally left unchanged, and what verification ran. If a claim depends on a live Docker runtime, include the runtime proof, not only checkout evidence.