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

The readOnlyHint annotation already establishes this as a safe read operation, lowering the disclosure burden. The description adds that the response includes base/head coverage, which is useful, but it does not discuss auth, error behavior, or pagination/return shape beyond that hint.

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?

Two compact sentences with no wasted words. The core purpose is front-loaded, and the REST endpoint is supplementary rather than redundant.

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 read-only GET tool with full schema coverage and an output-less design, the description is nearly complete: it names the resource, gives the endpoint pattern, and notes the coverage data returned. It stops short of describing the full response shape, but that is a minor gap at this complexity.

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 description coverage is 100%, so every parameter is already documented in the schema and the baseline is 3. The description's REST path template loosely maps to the parameters but adds no format, validation, or semantic detail beyond the structured fields.

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 states a specific verb and resource ('Get a single pull request's detail') and identifies the returned content ('including its base/head coverage'). The word 'single' implicitly distinguishes it from the sibling codecov_list_pulls, though that alternative is not named explicitly.

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?

Usage is implied rather than stated: 'a single pull request's detail' suggests this is for one PR rather than a list. There is no explicit when-to-use, when-not-to-use, or named alternative such as codecov_list_pulls.

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