set_star

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

The description says "idempotently," which merely repeats the idempotentHint annotation. It adds no new behavioral context such as authentication requirements, error behavior, or the effect on other email metadata. Since annotations already declare idempotency and non-read-only status, the description adds minimal value beyond structured data.

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 sentence with no wasted words. It is front-loaded with the operation (Set) and immediate qualifiers (one starred state, idempotently). Structurally, it is as concise as possible for the content it provides.

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 with five required parameters and no parameter documentation, the description is grossly incomplete. It lacks any mention of how to identify the target email, what the starred value means, or how to handle the response. While annotations cover idempotency and write behavior, they do not compensate for missing parameter context and usage instructions.

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 0%, and the description provides zero explanation of the five parameters (account_id, mailbox, uid_validity, uid, starred). It does not indicate how these parameters relate to the email being starred, what the starred boolean controls, or how uid_validity is used. The tool is unusable without schema-level or description-level parameter semantics.

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 sets one starred state, using the verb "Set" with a specific resource ("one starred state"). The qualifier "one" distinguishes it from the sibling set_star_batch, and "starred" separates it from set_read_state. While terse, it conveys the exact operation and primary scope.

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?

No guidance is provided on when to use this tool versus alternatives like set_star_batch or set_read_state. The description does not mention batch operations, read-state operations, or any exclusions or prerequisites, leaving the agent to infer usage from the name alone.

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