Tools & MCP servers

Tools are the things the agent can actually do — read a file, run a command, search the web. This page lists what ships built in, and how to add more through MCP servers or your own code.

Built-in tools

These are registered in every session. Each one is subject to your permission rules, so “available” doesn’t mean “unattended.”

Files

Tool	What it does
read	Read a file, with image support and large-file truncation.
write	Create a file or replace its contents.
edit	Make a targeted change inside an existing file.
patch	Apply a structured patch across files.
glob	Find files by name pattern.
grep	Search file contents, powered by ripgrep.

Running and delegating

Tool	What it does
shell	Run a command in your shell.
task	Delegate to a subagent. See Agents & subagents.
todo	Keep a visible task list for multi-step work.
question	Ask you a structured question mid-task.

Knowledge and context

Tool	What it does
bridge	Structural code intelligence — semantic search, symbols, references, trace.
memory	Recall, save, and forget durable facts across sessions.
skill	Load a skill’s instructions into the conversation.
webfetch	Fetch and read a URL.
websearch	Search the web.

Note

bridge and memory are covered in depth in Memory & context bridge. websearch availability depends on your provider or a configured search key.

Two more are behind experimental flags and off by default: an lsp tool for language-server queries, and a plan tool used by plan-mode switching in the CLI.

MCP servers

MCP — the Model Context Protocol — is an open standard for giving an agent extra tools. A GitHub MCP server adds GitHub tools; a database MCP server adds query tools. V3Code Terminal connects to them as a client.

Run /mcps to toggle servers on and off for the current session, and v3code mcp list to see every configured server with its status.

Local servers

A local server is a process V3Code starts and talks to over stdio.

{
  "mcp": {
    "my-tools": {
      "type": "local",
      "command": ["bun", "x", "some-mcp-server"],
      "environment": { "API_TOKEN": "..." },
      "enabled": true,
      "timeout": 5000,
    },
  },
}

Field	Meaning
command	The command and arguments to launch, as an array.
cwd	Working directory. Relative paths resolve from the workspace.
environment	Environment variables for the server process.
enabled	Whether it starts with the session.
timeout	Request timeout in milliseconds. Defaults to 5000.

Remote servers

A remote server is reached over HTTP.

{
  "mcp": {
    "company-api": {
      "type": "remote",
      "url": "https://mcp.example.com/sse",
      "headers": { "Authorization": "Bearer ..." },
      "enabled": true,
    },
  },
}

OAuth is detected automatically when the server advertises it. If the server needs specific client details, configure them under oauth — clientId, clientSecret, scope, and either callbackPort or a full redirectUri. The default callback is http://127.0.0.1:19876/mcp/oauth/callback. Set "oauth": false to switch auto-detection off.

Note

Keep credentials out of committed config. A token in a project’s v3code.json gets committed with it. Prefer environment variables, or put the server in your global ~/.config/v3code/v3code.json.

MCP tools ask permission too

Tools from an MCP server are not automatically trusted. They appear under their own tool names and can be governed by the same permission rules as anything else, so an unknown tool can be set to ask or denied outright.

Your own tools

For something small and project-specific, you don’t need a full MCP server. Drop a JavaScript or TypeScript file into a tool/ folder in your config directory — .v3code/tool/changelog.ts — and its exported tools are registered automatically.

The file name becomes the namespace: a default export from changelog.ts registers as changelog, and a named export recent registers as changelog_recent.

Plugins can contribute tools the same way. List them under plugin in your configuration.

Controlling what’s available

Three levers, from blunt to precise:

toolson/off per tool

A simple enable map in configuration. Good for turning something off globally.

permissionask / allow / deny

The real control. Works per tool and per pattern, and is what agents use to constrain themselves.

agent permissionper agent

Rules set inside an agent file apply only to that agent — how explore stays read-only.

Related

Permissions & privacy covers approval rules, Configuration covers where these blocks live, and MCP covers the editor’s MCP support.