count_eta_documents

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

No annotations are provided, so the description carries the full burden. It accurately states the core behavior (counting with optional filter) but does not disclose the return type (e.g., an integer) or any edge cases. However, for a simple read-only count operation, this is minimally sufficient.

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, front-loaded sentence that directly states the action and scope. Every word earns its place, with no redundancy or filler.

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 tool of this simplicity, the description adequately covers the core functionality. The schema covers parameters, and the sibling list provides context. However, it does not describe the return value or explicitly differentiate from query_eta_data, which could cause the agent to mis-select. Overall, it is nearly complete but leaves a few gaps.

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 input schema has 100% coverage for both parameters, with descriptions already explaining 'query' (optional, defaults to {}) and 'collection'. The description adds no additional parameter meaning beyond what the schema provides, so the baseline score of 3 applies.

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 counts documents in a collection with an optional query filter. The verb 'count' and resource 'documents in a collection' are specific and distinguish it from sibling tools like query_eta_data (returns documents) or aggregate_eta_data (performs aggregations).

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 no guidance on when to use this tool versus alternatives. It doesn't mention that this is for obtaining a count rather than retrieving documents, nor does it reference any sibling tools or exclusions. For an agent, the differentiation from query_eta_data is implied but not explicit.

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