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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description usefully adds that results preserve upstream grouping/league fields that 'can change as FotMob updates its payload', which warns about payload volatility. However, it also claims optional team/league filters that the schema does not expose, which is misleading rather than informative.

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 sentences, front-loaded with the core action, no filler. The volatility note is slightly tangential but still relevant to interpreting the response.

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 an output schema present, return values need no explanation, and the date/timezone contract is fully covered by the schema. The description is nonetheless incomplete because it advertises filtering capabilities that the tool does not accept, leaving the agent with a false model of the tool's surface.

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 date format (YYYYMMDD) and timezone default are already documented. The description adds no parameter detail and instead references 'optional team or league filters' that do not exist in the input schema, which could lead an agent to attempt unsupported arguments.

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 clear verb+resource ('Fetch FotMob match listings') and the scoping dimension ('requested date'). It does not name any sibling, so an agent cannot easily distinguish it from fotmob_team_fixtures or fotmob_match, but the purpose itself is unambiguous.

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?

There is no explicit when-to-use guidance and no alternatives named, despite many adjacent siblings (fotmob_team_fixtures, fotmob_match, fotmob_leagues). The mention of 'optional team or league filters' implies a filtering workflow but never says when this is preferable to the team/league-specific tools.

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