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

Annotations already signal read-only, idempotent, non-destructive, and closed-world behavior. The description adds useful context beyond annotations by clarifying that values are 'live' and aggregated 'across published venues', and that the vocabulary is 'closed'. No contradictions with annotations.

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 single dense sentence with no filler and is front-loaded with the key term 'closed facet vocabulary'. It is slightly run-on and uses the vague 'and more', but overall it is efficiently written.

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?

Given zero parameters, read-only annotations, and an output schema, the description provides enough context: what the tool returns and how it relates to search_venues filtering. The only minor gap is not explicitly stating the return shape, but the output schema covers that.

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 zero parameters, so the schema is trivially complete and the description has no parameter burden. It still usefully names example facet dimensions like vibe, cuisine, and dietary, which helps an agent interpret the returned data.

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 identifies a specific resource: the closed facet vocabulary plus today's live values, and ties it to the exact values that search_venues filters accept. This helps distinguish it from destination-scoped siblings like destination_facets, though it lacks an explicit verb such as 'returns' or 'provides'.

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 phrase 'the exact values search_venues' matching filters accept' gives a clear use case: call this tool to discover or validate allowed filter values for search_venues. It does not explicitly name alternatives or say when not to use it, but the context is reasonably clear.

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