CodexGuild DocsConnect coding agents to CodexGuild — MCP, REST and the codexguild skill
Quickstart Harness setup API reference

Getting started

Quickstart

Create an agent key, connect your coding agent over MCP and run your first sync.

1. Create an account and an agent key

  1. Create a free account.
  2. In the dashboard, click New agent, give it a name and pick its harness (Claude Code, Codex, Hermes…).
  3. Copy the key that starts with cgk_. It is shown only once.

Store it as an environment variable — never in a repository:

bash
export CODEXGUILD_API_KEY=cgk_xxxxxxxx_xxxxxxxxxxxxxxxxxxxxxxxx

Security: Treat the key like a password. If it leaks, revoke the agent in the dashboard and create a new one — revoked keys stop working immediately and can't be re-enabled.

2. Add the MCP server

Pick your harness below. The snippet is generated from GET https://api.codexguild.com/v1/setup/<harness>, so it always matches the current server.

1 · Set your key

Keep it in your shell profile or the harness’s secrets file — never in a repository.

bash
export CODEXGUILD_API_KEY=cgk_your_agent_key

2 · Add the MCP server

Runs npx -y @codexguild/mcp (Node 20+): every tool, plus automatic stack detection for sync and an offline audit of the skills you have installed.

~/.claude.json (user scope, via the CLI) or .mcp.json (project)

bash
claude mcp add-json codexguild --scope user '{"command":"npx","args":["-y","@codexguild/mcp"],"env":{"CODEXGUILD_API_KEY":"${CODEXGUILD_API_KEY}"}}'
json
{
  "mcpServers": {
    "codexguild": {
      "command": "npx",
      "args": [
        "-y",
        "@codexguild/mcp"
      ],
      "env": {
        "CODEXGUILD_API_KEY": "${CODEXGUILD_API_KEY}"
      }
    }
  }
}

3 · Install the codexguild skill

~/.claude/skills

bash
mkdir -p ~/.claude/skills/codexguild/references
curl -fsSL https://api.codexguild.com/.well-known/skills/codexguild/SKILL.md -o ~/.claude/skills/codexguild/SKILL.md
curl -fsSL https://api.codexguild.com/.well-known/skills/codexguild/references/api.md -o ~/.claude/skills/codexguild/references/api.md
curl -fsSL https://api.codexguild.com/.well-known/skills/codexguild/references/setup.md -o ~/.claude/skills/codexguild/references/setup.md

4 · Start every session with a sync

Ask your agent to run codexguild_sync, then codexguild_advise for setup proposals it will show you before applying.

Instruction files Claude Code loads: ~/.claude/CLAUDE.md · ./CLAUDE.md or ./.claude/CLAUDE.md · AGENTS.md (when no CLAUDE.md, v2.1.277+)

Claude Code does not read ~/.agents/skills — install the skill into ~/.claude/skills.

Check with `claude mcp list` (codexguild should be connected).

Verified

3. Verify the connection

Ask your agent:

Call codexguild_usage and tell me my plan.

You should see your plan and today's remaining quota. From the command line you can check the key directly:

bash
curl -s https://api.codexguild.com/v1/usage/today -H "Authorization: Bearer $CODEXGUILD_API_KEY"

4. Run your first sync

In a project directory, ask your agent to run codexguild_sync. It detects package.json, requirements.txt, pyproject.toml and go.mod, then returns:

  • releases and possibly-breaking changes for your stack, with the version the project uses,
  • the security status of skills your agent has installed,
  • new security advisories for coding agents,
  • scan-passed skills that fit the stack.

Tip: Make it automatic: run codexguild_advise once and approve the proposed CodexGuild section for your AGENTS.md / CLAUDE.md. It tells your agent to sync at the start of every session.

Next steps