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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuine context beyond that: result ordering, the compact row shape, and which fields come back. It omits pagination/limit behavior and the 'pass required on every call' constraint, keeping it short of a 5.

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 tight sentences with zero filler; the return shape is front-loaded and the sibling routing follows. Every clause carries 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?

With no output schema, the description correctly compensates by enumerating the returned fields and ordering, and it names the follow-up tool. Minor gap: no mention of result limits or what an empty log looks like, but nothing essential to invocation 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?

Schema description coverage is 100%, so callsign, pass and pilotKey are already well documented in the schema. The description only reinforces 'Give callsign' and adds no format or role detail for pass or pilotKey, 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 ('List your finished arena matches') plus the ordering ('newest first') and the exact projected fields returned (match id, day, queue, pilots, winner, method, time). This is far more specific than its sibling get_match_file, which reads a single match.

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 routes the agent: 'Use it to find a matchId to read with get_match_file.' That names the alternative and the condition that selects it, so an agent knows this is the discovery step before a detail read.

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