How do I add external tools to Claude Code?
Three paths. MCP/Composio: connect a tool through Composio's Tool Router, which issues a per-session MCP URL you register with your agent — it then auto-registers as an MCP tool your agent can call directly. (Composio's earlier Rube gateway was retired in May 2026.) SKILL.md: install a skill file that contains the API code and procedure — your agent reads it and executes with its built-in tools (terminal, HTTP). Custom MCP server: write a local MCP server that exposes your tool, configure it in your agent's config. Most operators start with path 2 (skill files) because they require no infrastructure — just copy a folder into your agent's skills directory and it works. Path 1 adds auth management; path 3 is for custom/internal tools.
Related questions
What is the fastest way to add a tool to Claude Code?
An MCP server for access, plus a skill telling the agent how to use it. AgentKit Works packages both together so installation is a single pasted prompt — the agent reads INSTALL.md, places the skill where the platform expects it, and verifies each step before reporting done.
Do I need to write code to add a tool?
No. MCP servers are configured, not coded, and skills are Markdown. AgentKit Works kits ship a ready-to-paste MCP configuration block and a SKILL.md, which is why installation takes about two minutes rather than an afternoon of wiring.
How do I know the tool was installed correctly?
Verify with evidence rather than assertion. Every AgentKit Works kit includes explicit verification steps in install.json — the installing agent runs a real call and shows the result, because an agent reporting success is not the same as the integration working.
Can the same tool setup work in Codex or Cursor?
Largely yes — SKILL.md is an open standard and MCP is cross-client. AgentKit Works verifies its kits on Claude Code and ships them compatible with Codex CLI, Hermes Agent and 30+ other tools, with the destination path being the only thing that differs per platform.
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