---
title: "Accept only tokens issued for your MCP · Agent Wranglers"
url: https://agentwranglers.se/playbook/adversarial-testing/ai-agents-and-models/mcp-token-audience
updated: 2026-10-20
licence: "All rights reserved"
---

# Accept only tokens issued for your MCP server

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

- Level: Required
- Chapter: [AI agents and models](https://agentwranglers.se/playbook/adversarial-testing/ai-agents-and-models)
- Rule: An MCP server you run accepts only access tokens issued for it. It never passes a client's token on to other APIs.
- How: Check the token's audience and issuer on every request, as the MCP authorization specification requires. Get separate tokens for the APIs behind the server. Ask each user for consent per client before you connect them to another service.
- Check: Send the server a valid token that was issued for a different API. It answers 401.

**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 security testing playbook: https://agentwranglers.se/playbook/adversarial-testing/ai-agents-and-models/mcp-token-audience`.

- Previous: [Break the lethal trifecta](https://agentwranglers.se/playbook/adversarial-testing/ai-agents-and-models/lethal-trifecta)
- Next: [Use models and data from trusted sources](https://agentwranglers.se/playbook/adversarial-testing/ai-agents-and-models/trusted-model-sources)
- [AI agents and models](https://agentwranglers.se/playbook/adversarial-testing/ai-agents-and-models)