Agents

MCP

Cactus's help as tools, over streamable HTTP. It answers from the published pages, with no account and no sign-in.

https://mcp.heycactus.ai/p/cactus/mcp

claude mcp add --transport http --scope user cactus https://mcp.heycactus.ai/p/cactus/mcp

A2A

Send a question as an A2A message and get one answer back, with the pages it cites. No sign-in.

https://mcp.heycactus.ai/p/cactus/a2a

Tools for browser agents

An agent running in your browser can use Cactus's help as WebMCP tools, which this site hands to the browser on every page. Every one of them only reads, except open_messenger.

• ask_cactus

  Asks a question and returns Cactus's answer, with the pages it cites.

• open_messenger

  Opens the Messenger, with a message sent. Only on a site that carries the Messenger, never on this one.

• search_help

  Finds the pages about a word or a feature, with the slug each one is read by.

  {"query":"sign in"}

  Run

• read_help_page

  Reads one page in full, by its slug.

  {"slug":"what-cactus-does"}

  Run

• list_topics

  Lists this site's sections, with the titles and slugs of their pages.

  no input

  Run

• read_timeline

  Reads the releases, one line each: the day, the theme, the title and what kind of change it was.

  no input

  Run

search_help, read_help_page, list_topics and read_timeline are on while this site is live.

WebMCP is still behind a flag. To turn it on:

• Chrome: open chrome://flags/#enable-webmcp-testing, set it to Enabled, and relaunch.
• Edge Canary or Dev: open about://flags/#enable-webmcp-testing, set WebMCP for testing to Enabled, and restart.

Files for agents

• llms.txt

  Every page on this site, one line each, and when to read it.

  https://cactus.heycactus.ai/llms.txt

• llms-full.txt

  Every page in one file.

  https://cactus.heycactus.ai/llms-full.txt

• Markdown

  Every page as markdown, at its own address with /md on the end.

  https://cactus.heycactus.ai/<page>/md

• OpenAPI

  What this site answers on, as an OpenAPI description.

  https://cactus.heycactus.ai/openapi.json

• MCP server card

  The MCP address, how it is signed in to, and the tools it answers with.

  https://cactus.heycactus.ai/.well-known/mcp/server-card.json

• A2A agent card

  The A2A address and what it does.

  https://cactus.heycactus.ai/.well-known/agent-card.json

Signing in

A public site needs none. A site its team keeps to itself reads to a member of the team: in a browser signed in to Cactus, or to an agent with a token from this site's own sign-in.

• auth.md

  How an agent signs in, with a browser or without one, step by step.

  https://cactus.heycactus.ai/auth.md

• Authorization server

  This site's OAuth metadata.

  https://cactus.heycactus.ai/.well-known/oauth-authorization-server

A token from the sign-in carries these scopes:

• cactus:read

  Read your team's pages, code map and past conversations

• cactus:ask

  Ask Cactus questions and start investigations; each creates a conversation