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

Annotations already mark this as read-only, idempotent, and non-destructive, so the bar is lower. The description adds valuable behavioral context beyond annotations: it explains that results are derived from site data and therefore reflect what's loaded, not a complete transfer market. This helps set expectations about data accuracy and completeness.

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 two sentences with zero filler. It front-loads the core purpose and then provides a succinct, relevant caveat about data provenance. Every sentence earns its place.

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 list tool with two well-documented parameters and no output schema, the description covers the essential context: what the tool returns (arrivals, departures, coach changes), the data source, and its limitation. It could mention response format, but that is not critical for this level of complexity, so a 4 is appropriate.

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%: both 'season' and 'locale' have clear, self-descriptive descriptions. The tool description adds no further parameter-level meaning, so the baseline score of 3 applies (the schema does the heavy lifting).

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 resource ('squad movements in a season') and the specific verb ('get who arrived and who left, including coaching changes'). It is unambiguous and distinguishes itself from the listed siblings (matches, standings, articles, etc.), which are clearly different domains.

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?

The description implies when to use it (when you need squad movements for a season) and adds a caveat about the data being site-derived, not a full transfer market. However, it never explicitly says when NOT to use it or names any alternative tools, so the guidance is implied rather than explicit.

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