Install the MCP server
Connect Claude, Cursor or Codex to the B3OS MCP server so your agent can scrape, run sandboxes and call marketplace actions.
You need a key in B3OS_API_KEY (get one) and Node.js for npx.
Register the server with your client
The CLI writes the B3OS server into your client's MCP configuration:
bashnpx b3os mcp install --client claude
--client takes claude, cursor or codex. The entry starts the local server, npx -y @b3os/mcp, which reads B3OS_API_KEY from your environment (or the token from b3os login), so the client's configuration holds no secret. Restart the client afterwards.
Ask for something that needs a tool
Try a prompt that needs the web:
textScrape https://example.com and tell me in one sentence what the page is for.
The client calls vision_scrape, gets the page as Markdown and answers from it. B3OS tool names start with the product they call, such as vision_scrape, render_screenshot and sandbox_exec; the MCP server page lists them all.
Reach a marketplace action
Pack actions do not crowd the tool list. The agent finds them in three calls:
textFind a B3OS action that creates a GitHub issue and tell me which inputs it needs.
It calls actions_search with your words, actions_describe for the input schema of the best match, and actions_call to run it once you store a GitHub connection in the vault.
Configure it by hand
The remote server lives at https://beta-api.b3os.org/mcp: stateless Streamable HTTP, authenticated with your key as a bearer token. The local server runs on your machine over stdio. The two list slightly different tools in this beta; see the tool table.
bashclaude mcp add --transport http b3os https://beta-api.b3os.org/mcp \ --header "Authorization: Bearer $B3OS_API_KEY"
For clients that read an mcpServers JSON file, such as Cursor's ~/.cursor/mcp.json:
json{ "mcpServers": { "b3os": { "url": "https://beta-api.b3os.org/mcp", "headers": { "Authorization": "Bearer b3os_sk_..." } } }}
@b3os/mcp is the local stdio server, the one b3os mcp install sets up:
json{ "mcpServers": { "b3os": { "command": "npx", "args": ["-y", "@b3os/mcp"], "env": { "B3OS_API_KEY": "b3os_sk_..." } } }}
Paste your own key where the examples show b3os_sk_.... A key with fewer scopes gives the agent fewer powers: tools whose operations need a scope the key lacks fail with forbidden.
Next
- MCP server reference: the tools each server lists, exposing chosen packs directly, and running routines.
- Run an agent in a sandbox to put the agent itself on the node.