Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), and the description adds genuinely new context: tokens are short-lived, require the mcp:write scope, and bypass normal production key flows. Idempotency is left to the annotation rather than restated, which is appropriate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the action, then the usage caveat and the scope requirement. No padding; every clause adds information an agent needs.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Auth scope and dev-vs-production behavior are well covered, which is substantial for a 3-parameter tool with no output schema. However, the 'mode' enum (live/replay) is left entirely unexplained in both schema and description, which is a real gap for an agent choosing a value.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 33% — only user_id is documented in the schema, and the description does not explain the 'mode' enum (live/replay) or session_id format at all. The phrases 'one participant' and 'join a session' give weak grounding for user_id and session_id, but the most ambiguous parameter (mode) is unexplained everywhere.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Mint a short-lived connection token') with the exact scope ('for one participant to join a session from a browser'), which clearly separates it from siblings like create_session and create_server_key. An agent can tell what this produces and for whom without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states the intended context ('for trying the integration locally') and the exclusion ('In production the app's server mints these with its own key'), so an agent knows both when to call it and when not to. The only minor gap is that it doesn't name a sibling tool as the production-side alternative, but the alternative behavior is described.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.