First tool call

First tool call

After Claude Desktop is configured (see Quickstart), your first interaction usually looks like this:

You: “Post ‘hello from Claude’ in #general of my test guild.”

This single sentence triggers a precise sequence inside Claude.

What Claude does internally

1. Discovery — tools/list. Claude sends a JSON-RPC tools/list request over stdio. discord-mcp returns 192 tool definitions, each with a four-section description.
2. Selection. Claude scans the tool catalog, looking for ones whose Purpose line matches “post a message to a channel.” It picks messages_send.
3. Argument extraction. Claude reads messages_send’s input schema and fills the required fields (channel_id, content) by either inferring from context or asking you to confirm.
4. Invocation — tools/call. Claude sends a tools/call JSON-RPC frame with name: "messages_send" and the structured arguments.
5. Execution. discord-mcp validates the args (zod), resolves the channel, applies resilience policies (retry / circuit-breaker via Cockatiel), issues the REST call, redacts the response per the privacy policy, and returns it.
6. Display. Claude renders the success result — typically a confirmation with the created message’s ID and timestamp.

The four-section description format

Every tool’s description follows the same agent-optimized layout. Here is the contract for messages_send (abridged):

Purpose: Send a new message to a Discord channel.
When to use: User asks to post, send, share, or announce something in a channel.
When NOT to use: When editing an existing message (use messages_edit) or replying
  inside a thread without creating one (use threads_create + messages_send).
Returns: { id, channel_id, content, author, timestamp, ... } — the created Message object.

The four-section structure is what lets Claude pick the right tool from 192 candidates without hallucinating one that does not exist.

Why structured output matters

The tool’s return value is always structured JSON, not free-form text. Claude re-uses fields like id from the response in follow-up tool calls, e.g. to add a reaction (reactions_add) or pin the message (messages_pin). This is why discord-mcp ships every endpoint as a tool rather than an ad-hoc shell.

Next

• Client setup — same flow but with Cursor, Claude Code, or generic clients.
• Tools — full reference for all 192 tools (auto-generated).