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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds substantial behavioral context beyond that: 'Parallel-safe: yes. Upstream cost: 1–2,' the Dota limitation ('may NOT_IMPLEMENTED or weak worldRanking'), and the pagination caveat ('UFC world scope spans every division; page with it rather than raising limit'). These are exactly the kind of behavioral traits an agent needs and that structured annotations do not convey.

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?

The description is information-dense with no filler: every section earns its place, from purpose and alternatives to per-game scope, parallel-safety, cost, and an example. It uses clear section headers and bullets, keeping the content scannable. Despite its length, it is appropriately sized for the tool's complexity.

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 multi-game standings tool with 10 parameters, the description is remarkably complete: it covers use cases, exclusions, per-game parameter requirements, known limitations, operational traits (parallel-safety, cost), pagination guidance, and a concrete example. Since an output schema exists, return-value documentation is unnecessary. Nothing an agent needs to call this tool 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?

Although the schema already achieves 100% description coverage, the description adds critical cross-parameter semantics that the schema cannot express: game-dependent required keys (lol: leagueId OR tournamentId; cs2: omit for world rankings; eventId for event standings; dota2: best-effort worldRanking only). It also adds usage nuance for cursor and limit in the UFC pagination note. This goes well beyond the baseline for high schema coverage and meaningfully improves parameter selection.

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 clear, specific statement: 'League/event standings or world/division rankings normalized to ranked rows.' It names the resource (standings/rankings), the output format (normalized rows), and immediately distinguishes from siblings via 'Prefer over: raw standings via call_api' and 'Do not use when: single team form → team_profile; live scores → live_matches.' An agent can confidently tell this apart from the listed alternatives.

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?

Usage guidance is explicit and structured: a 'When to use' bullet list covers table/playoff picture and per-game use cases, a 'Do not use when' section names exact alternatives (team_profile for single-team form, live_matches for live scores), and a per-game 'Required scope keys' section tells the agent exactly which parameters to provide for each game. This is comprehensive, actionable routing guidance.

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