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

Annotations already establish this is a read-only, closed-world lookup, so the bar is lower; the description still adds conditional behavior ('when available' for the city guide) and characterizes the athlete payload as those 'who want sponsors'. It stops short of describing not-found/error behavior.

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?

A single front-loaded sentence that leads with the core purpose before nesting details. Dense parenthetical enumeration of guide contents is justified given no output schema, though it reads as a long run-on.

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 compensates by enumerating the return payload (facts, guide sub-sections, athletes), and the 'when available' caveat flags non-uniform responses. Missing only edge-case behavior for invalid or unknown slugs.

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?

Only one parameter at 100% schema coverage, so the baseline is 3; the description earns extra by giving the parameter's provenance ('from search_races'), telling the agent the slug is a value produced by another tool rather than an arbitrary string.

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 (get) and resource (race by slug) and enumerates exactly what comes back: facts, race-weekend guide, and athletes seeking sponsors. This distinguishes it clearly from siblings like get_training_guide or get_athlete.

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 tells the agent where the slug comes from ('from search_races'), which routes from the sibling search tool. It does not state when not to use it or what happens for an unknown slug, so it falls short of a full when/when-not treatment.

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