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

The annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds context that it returns the full catalogue with headline facts and boolean flags, but it does not describe potential performance implications (e.g., large payload) or pagination behavior. While this is useful, the lack of such details means it doesn't go beyond the annotations sufficiently to warrant a higher score.

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 a compact two-sentence block that front-loads the core purpose and scope. It includes all essential information—content, flags, URLs, usage guidance, and no-argument note—with zero filler. Every sentence earns its place, and the structure is well-organized.

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?

The tool is simple (no parameters, no output schema), and the annotations cover read-only and idempotent behavior. The description fully explains what the response contains boats, flags, URLs—and explicitly warns it is not availability. Nothing an agent needs to correctly invoke this tool is missing, given the absence of an output schema.

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 tool has no parameters, so the schema is trivially complete. The description effectively explains that no arguments are needed)Skip, which directly addresses the absence of parameters. It also explains the return payload's structure (features, URLs), which adds value not derivable from the empty schema. This is more than the baseline 4 for zero parameters.

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 enumerates every bookable Angling Lines carp fishing venue in France, with a specific verb 'List' and a defined resource. It explicitly distinguishes itself from the sibling search_venues by noting that feature keys match filter names, which is a specific and actionable distinction. This is not a tautology and immediately conveys the tool's unique role.

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 provides explicit guidance on when to use this tool versus alternatives, directly recommending 'prefer search_venues to filter server-side'. It also clarifies that it returns the full catalogue and is not an availability check, which distinguishes it from venues_available_on_date. This is high-quality usage guidance with clear exclusions.

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