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

With no annotations, the description carries the behavioral burden and does well: it discloses the default behavior when query is omitted, explains that query filters or searches, and warns that get_fixtures returns empty for cups. It does not state auth/rate-limit traits or explicitly that the operation is read-only, but 'List' strongly implies a safe read.

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 dense and front-loaded, leading with the core action, then default behavior, then the chaining rule. All sentences carry useful information, though the multiple clauses in one block make it slightly crammed.

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 two-parameter list tool with no output schema, the description explains the default return (featured major competitions with keys) and how query changes that. It does not describe the full return shape (e.g. what fields accompany each key), leaving a minor gap.

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 coverage is 100%, so both parameters are already documented in the schema. The description reinforces query behavior and examples but adds little beyond the schema's own 'Omit for all featured competitions with keys' wording. Baseline 3 is appropriate.

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: list football competition and league API keys. It also explicitly differentiates downstream behavior (get_league_fixtures vs get_fixtures), so an agent can distinguish this from sibling tools.

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 before fetching fixtures when the user names a league or tournament.' It also names the correct and incorrect alternatives (get_league_fixtures vs get_fixtures), covering both when to use this tool and which sibling to chain next.

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