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

With no annotations, the description carries the full behavioral burden; it does disclose two useful traits beyond the schema — automatic competition-key resolution and server-side conversion to API DD/MM/YYYY. It says nothing about failure modes (unknown competition, no fixtures that day), whether the call is read-only, or what volume of fixtures comes back.

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 tight sentences, front-loaded with purpose before behavior and usage instruction; nothing is padded. Minor redundancy in restating competition examples already present in the schema keeps it from a 5.

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?

No output schema and only four flat parameters, so the description needs only to establish purpose, date/format handling, and the auto-resolution behavior — all of which it does. The remaining gap is edge-case behavior (empty result sets, unrecognized competition names), which an agent would likely need to call the tool confidently.

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 schema already documents all four parameters, and the description's query examples merely repeat the schema's own examples. The one added signal is the anti-guessing instruction tied to the date parameter, which reinforces that the agent must supply a real date rather than infer one.

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 ('Football fixtures for one competition on one date') and adds scope that pins it down: exactly one competition, exactly one date. It also discloses the automatic league-key resolution (World Cup → WorldCupBrazil2014), which separates this from a generic search tool.

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?

Gives an explicit directive: 'Always call this for fixtures today — do not guess dates or schedules,' which is a real routing signal rather than an implied one. It does not name the alternatives (e.g. get_live_scores for in-progress matches, get_match for a single fixture), so the boundary with siblings is left to inference.

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