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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description's 'It only reads' is consistent with that. The description adds value by detailing what the response contains, which the schema does not cover. The 'Never promise an address' caveat is an extra behavioral instruction. No contradiction with annotations, and the description supplements them.

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, each serving a distinct purpose: what it returns, read-only confirmation, sibling for actions, and a safety caveat. The core purpose is front-loaded in the first sentence, and there is no wasted wording. This is a model of concise, well-structured description.

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?

Despite having no output schema, the description enumerates the return content. With one required parameter, strong annotations, and explicit routing to a sibling for mutations, an agent has everything needed to call the tool correctly. The safety note adds an important operational constraint.

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 coverage for match_id is 100% with a clear description ('The match_id from check_matches'). The tool description adds no new parameter-specific meaning beyond what the schema already provides. The phrase 'one match' implicitly clarifies match_id identifies a single match, but this is marginal, 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?

The description opens with a specific verb and resource: 'Get the full details of one match', then enumerates the exact content returned (what the other person wrote, why they matched, opener, status). It distinguishes itself from the sibling respond_to_match by stating it only reads, making the tool's purpose unmistakable.

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 description explicitly routes the agent away from this tool for actions: 'To accept, decline or block the match, call respond_to_match.' It also implies usage after obtaining a match_id from check_matches, and the safety note 'Never promise an address' adds an operational guideline. This gives clear when-to-use and when-not-to-use context.

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