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

Annotations already mark this destructive, idempotent, non-readOnly and open-world, so the safety profile is covered. The description adds two things annotations cannot: the required auth scope (anonping:match) and the blast radius (only the pending wait, not a live matched conversation). It does not state what happens when no wait is pending, but idempotentHint implies a no-op.

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?

Three short sentences, front-loaded with the action, then the boundary, then the auth prerequisite. No filler and nothing buried.

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?

Zero params, no output schema, and annotations carry the mutation/idempotency profile, so little is left to explain. The description covers the one non-obvious operational fact (required scope) and the effect boundary; only the no-op-when-idle behavior is left to inference.

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?

The tool takes zero parameters, which is the baseline-4 case; there is no schema surface the description needs to compensate for. The scope string is arguably parameter-like context but is not an input field.

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 ('Cancel the current wait') and draws an explicit boundary against the sibling end_conversation by specifying it does not end an already matched conversation. An agent can route between cancel_match and end_conversation without opening either 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?

The exclusion ('Does not end an already matched conversation') implicitly routes matched-conversation teardown to end_conversation, and the required scope tells the agent when it is even callable. No alternative tool is named outright, so it stops short of fully explicit when/when-not/alternatives guidance.

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