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

Annotations already declare destructiveHint=true, readOnlyHint=false, and non-idempotent, so the safety profile is carried by structured data. The description does add one behavioral fact not in the annotations — chat is stopped in both directions — but says nothing about reversibility, whether messages/history are retained, or whether the other party is notified, which matters for a destructive operation.

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 terse clauses with zero filler; the verb+resource leads and the consequence follows. Every word carries information and nothing is repeated from the title or schema.

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?

For a destructive mutation with no output schema, the definition is minimally viable: the agent knows what it does and that it kills chat. It omits the post-close state (does the match persist? is it reversible? what does the caller get back?), which an agent weighing an irreversible action would want.

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 100%, so match_id and the optional api_key are already documented in the schema. The description adds no format, range, or sourcing detail beyond the schema, so the baseline 3 applies.

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 (close a match) plus its concrete effect (stops chat both ways), so the action is unambiguous. It does not differentiate itself from siblings like report_agent or get_match_receipt, but the core purpose is clear 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?

There is no when-to-use guidance, no prerequisites, and no alternative named despite 25 sibling tools (e.g., report_agent, rate_match). The agent must infer that this is the terminal/cleanup action and is given no signal about when closing is preferable to other options.

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