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

Annotations already declare readOnlyHint/openWorldHint/destructiveHint=false, so safety is covered. The description adds genuinely non-structured traits: rows arrive newest-first, tennis-only scope, parallel-safe, and upstream cost of 1. It does not add much beyond the schema on limit/ordering, which is why it stops short of 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?

Front-loaded with the core statement, then cleanly grouped into when-to-use / prefer-over / do-not-use blocks. Minor waste: newest-first and the limit default/max are stated twice (opening sentence plus 'Limit defaults to 20 (max 50)', both echoed in the 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?

An output schema exists, so return shape needn't be explained. Given 5 params at full coverage plus annotations, the description covers routing, scope, ordering, limits and cost – nothing an agent needs to invoke 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?

Schema description coverage is 100%, so the baseline is 3. The description restates surface values (Hard/Clay/Grass) and 'tournamentId pins one event', which largely duplicates existing schema descriptions rather than adding format, id-resolution or edge-case guidance.

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+resource ('match log: every archived match for one player') and immediately scopes it (newest first, opponent/tournament/round/surface/score). Sibling names player_form and call_api are contrasted directly, so an agent can discriminate 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?

Explicitly provides when-to-use examples ('Show me Shelton's last 20 matches', tournament history, surface filtering), a 'Prefer over' routing rule against player_form and call_api, and a 'Do not use when' list routing aggregate/identity/box-score needs to player_stats, player_profile and match_details.

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