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

The description goes well beyond the readOnlyHint annotation by explaining the data semantics: definitions of joiners (with a data-availability caveat for 2026-08-02 onward), movers, and leavers, as well as the period defaulting to trailing 30 days. This is substantive behavioral context that is not evident from the annotations or schema.

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 well-structured and front-loaded: the first line states the core purpose, then each sentence adds necessary clarification about definitions and defaults. No redundant information is present, and the length is appropriate for the complexity of the subject.

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?

Despite the absence of an output schema, the description sufficiently describes the return contents: a daily category series, net growth, period totals, and the 'won from / lost to' breakdown. It also covers data definitions and default periods, making the tool's behavior and return value understandable without further documentation.

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%, with descriptions for all three parameters (key, from, to). The description adds context like 'Defaults to the trailing 30 days,' but this is largely already captured in the schema defaults. The description does not introduce new parameter syntax or format details, so a baseline score of 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?

The description clearly states the tool's purpose with a specific verb and resource: "Get an access point's churn." It then elaborates on what churn means (joiner/mover/leaver activity) and distinguishes it from sibling tools like get_access_point and get_country_churn by focusing on the access point's churn-specific data.

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 clear context for when to use the tool (to retrieve churn data for a specific access point) but does not explicitly exclude alternatives or reference sibling tools like get_country_churn. It lacks explicit when-to-use/not-to-use guidance, but the specificity makes the intended usage clear.

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