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

Annotations already declare this is a non-destructive, non-open-world write, so the safety profile is covered. The description usefully constrains the reason to a fixed set rather than free text, but it never says what the write does — whether a new rating replaces a prior one, whether it is idempotent, or any auth/ownership requirement.

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?

Three short sentences with the trigger condition front-loaded and no filler. The 'Not for medical questions, emergencies or a crisis' clause is safety boilerplate loosely related to the tool's purpose and dilutes focus slightly.

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?

With full schema coverage, annotations, and an output schema, the description only needs to establish trigger and scope, which it does. The remaining gap is behavioral: it does not address re-rating or duplicate submissions for the same session.

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 the baseline is 3 — the enum values, the 1–5 star bounds, and session_id are all documented in the schema. The description adds only the framing that the reason is 'fixed' and not free text, which is marginal on top of the enum.

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 names a specific verb+resource pairing (giving stars for a session) and the trigger condition, so an agent can map it to a rating action without opening the schema. It does not explicitly differentiate from the sibling like_session, leaving the stars-vs-like distinction to inference.

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?

It states when to use it ('when the user gives stars for a session they just heard') and gives explicit exclusions: not for medical questions, emergencies or crisis, and not for free-text comments. It does not name an alternative tool for those out-of-scope cases, so routing on the negative side is incomplete.

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