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

Annotations already indicate read-only and idempotent behavior. The description adds valuable context beyond annotations: data comes from an external provider, may lag behind live results, and `syncedAt` signals freshness. This helps set expectations about data accuracy.

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 compact and front-loaded: it states the core purpose, then clarifies list semantics, and ends with a caveat about data freshness. Every clause adds useful information without unnecessary filler.

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 simple read-only tool with two optional parameters and no output schema, the description covers the important behavioral aspects: return sections, live-match inclusion, freshness indicator, and external data caveat. The main gap is the lack of any description of `limit` semantics, but overall an agent can call this tool correctly.

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?

The description adds no meaning for the two parameters. `locale` has a schema description, but `limit` has only type/default/range constraints; the description does not explain how `limit` affects the lists or whether it applies per category. With 50% schema coverage, the description should compensate more.

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 clearly states the tool provides River's fixture and recent results, with explicit definitions of 'upcoming' and 'recent'. It is distinct from siblings like get_match_report or get_standings by its focus on fixture lists and results, though it does not explicitly name those 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 is implied: use this tool for upcoming and recent fixtures, and the note about external data lagging gives caution for live-result needs. However, it does not explicitly say when to use this tool over siblings or when not to use it.

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