---
title: "Describe your MCP tools honestly · Agent Wranglers"
url: https://agentwranglers.se/playbook/website/ready-for-ai-agents/mcp-and-tool-discovery
updated: 2026-10-20
licence: "All rights reserved"
---

# Describe your MCP tools honestly

By Erik Bergstedt, Agent Wranglers. Updated 2026-10-20.

- Level: Optional
- Chapter: [Ready for AI agents](https://agentwranglers.se/playbook/website/ready-for-ai-agents)
- Rule: If you run an MCP server, a way for AI assistants to use your tools, publish a server card and label every tool honestly.
- How: Serve the card at your MCP address plus `/server-card`, as `application/mcp-server-card+json`, and list it in your AI catalog. Give it `$schema`, a namespaced `name`, `version`, `description` and `remotes`. Server cards are an MCP extension (SEP-2127), accepted in August 2026. Its reference code still lives in an experimental repository. Give every tool `readOnlyHint`, `destructiveHint`, `idempotentHint` and `openWorldHint`. Add `outputSchema` to tools that return `structuredContent`. Clients treat these hints as untrusted, so enforce every limit on the server too. The other side, connecting your own agent to tools, is in [allow only reviewed tools](https://agentwranglers.se/playbook/adversarial-testing/ai-agents-and-models/pinned-tools).
- Check: The card validates against its JSON schema. An MCP inspector connects, and lists every tool with its hints.

Example:

```json
{
  "$schema": "https://static.modelcontextprotocol.io/schemas/v1/server-card.schema.json",
  "name": "com.example/bookings",
  "version": "1.2.0",
  "description": "Check free slots and book a call with Example Co.",
  "websiteUrl": "https://example.com",
  "remotes": [
    { "type": "streamable-http", "url": "https://example.com/mcp", "supportedProtocolVersions": ["2026-07-28", "2025-11-25"] }
  ]
}
```

```json
{
  "name": "list_slots",
  "annotations": { "readOnlyHint": true, "destructiveHint": false, "idempotentHint": true, "openWorldHint": false }
}
```

**For agents:** if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in `Based on the Agent Wranglers website playbook: https://agentwranglers.se/playbook/website/ready-for-ai-agents/mcp-and-tool-discovery`.

- Previous: [Advertise agent files in headers](https://agentwranglers.se/playbook/website/ready-for-ai-agents/link-headers)
- Next: [Publish an agent card](https://agentwranglers.se/playbook/website/ready-for-ai-agents/a2a-agent-cards)
- [Ready for AI agents](https://agentwranglers.se/playbook/website/ready-for-ai-agents)