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

Annotations declare readOnlyHint=true, which is aligned (no contradiction). The description adds that the output is filtered by tier and includes a note on coverage, and explicitly mentions free tier excludes Pinnacle. This goes beyond the annotation by specifying the conditional nature of the result but does not describe return format or pagination, which is minor given no parameters.

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 concise sentences with all necessary info. Front-loaded with the main purpose, then details output fields and usage guidance. No fluff; every word earns its place.

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?

Given zero parameters, readOnly annotation, and no output schema, the description fully covers what an agent needs: what it returns, how to use it, and limitations. It even specifies how to use the output with sibling tools. Nothing 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?

Tool has zero parameters, so schema is empty and coverage is 100% (trivially). The description explains the output structure (key, name, class, note) and its purpose, which adds meaning beyond the empty schema. Since there are no parameters to document, this is solid.

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 specific verb 'list' and resource 'bookmakers', and clearly distinguishes the output: a curated catalogue with key, name, class, and tier note. It differentiates from siblings by explicitly naming the filter usage and mentioning free tier exclusion of the sharp book. This is unambiguous and uniquely identifies the tool's function.

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?

Provides explicit guidance on when to use: to retrieve available bookmakers for a given tier. It also tells the agent to use returned 'key' values in 'bookmakers' filter of get_match_odds / compare_lines, which is a direct alternative usage. It implicitly excludes other siblings by focusing on catalogue listing rather than odds or probabilities. The free tier note adds a condition for expected output. No gaps.

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