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

Annotations cover the safety profile (readOnlyHint=false, openWorldHint=true, non-idempotent, non-destructive), and the description adds genuinely non-obvious behavior: it reuses existing wait/conversation state, inherits site age/ban/membership/delay rules, schedules no background work, drives heartbeat_match on a 15s cadence, and requires the anonping:match scope. This is rich context beyond the structured fields.

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?

Four sentences, front-loaded with the trigger condition, and each sentence carries distinct information (trigger, resume semantics, heartbeat cadence, no background work, scope). The third sentence packing age/ban/membership/delay rules is dense but still earns its place.

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?

With no output schema, no parameters, and only four annotations, the description carries the burden well: it explains invocation timing, state reuse, polling behavior via heartbeat_match, absence of background work, and required scope. Nothing an agent needs to call it correctly is missing.

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 with an empty schema, so the baseline is 4 and there is nothing parameter-level for the description to compensate for. The scope requirement mentioned in the description is auth/logistics rather than a parameter, so it doesn't lower the score.

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?

The description states a specific verb+resource ('Start anonymous matching') and scopes it precisely to anonymous matching, which cleanly separates it from siblings like cancel_match, heartbeat_match, and send_message. It also clarifies the resume semantics (reuses an existing wait or active conversation) that an agent could not infer from the name alone.

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?

It gives an explicit trigger condition ('only when the user asks') and a continuing condition ('only while the user wants to keep waiting'), plus the companion cadence for heartbeat_match every 15 seconds. It does not explicitly name stopping/ending alternatives (cancel_match, end_conversation), so the routing guidance is strong but not exhaustive.

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