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

Annotations only declare readOnlyHint=true, so the description carries the behavioral burden. It adds valuable context: only OPEN markets are returned by default, RESULTED selections never carry a price under any query, and a finished fixture can 404 as normal market lifecycle rather than an outage. These details go well beyond what the annotations reveal.

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?

Three dense sentences, each earning its place: purpose is front-loaded, usage guidance follows, and behavioral caveats close out the description. No filler or repetition of schema boilerplate.

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 adequately names the return contents and covers the key edge cases (closed/suspended/resulted filtering, missing prices, 404 on finished fixtures). An agent has enough context to invoke the tool correctly and interpret unexpected results.

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 reinforces the include parameter's default behavior and the resulted-price caveat, but it does not meaningfully add parameter syntax or type information beyond what the schema already documents.

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: 'One fixture in full by id' and enumerates exactly what is returned (normalized markets with canonical key, tier, structure, status, decimal price, no-vig probability). It also distinguishes itself from the odds-listing siblings by specifying it is the follow-up call when a single match needs its whole market list.

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 says when to use it: after get_live_odds or get_prematch_odds returns an id, when one match needs its entire market list. This names the alternatives and the condition that selects this tool, leaving no ambiguity about the intended call sequence.

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