list_threads

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

No annotations provided, but the description indicates this is a read operation (listing) and specifies the return format (per thread with count and date). It does not mention destructive actions or auth needs, but the behavior is clear from the context.

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 concise with two sentences and no fluff. It could be slightly improved by front-loading key details, but it is well-structured for a short description.

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?

The description covers the return format (message count, latest date) and basic purpose, but lacks details on parameter behavior (e.g., whether subject_contains is partial match) and pagination. Given the 3 optional parameters and existing output schema, it is adequate but has 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 description does not mention any of the three parameters (subject_contains, sender, limit) or explain how they affect results. With 0% schema description coverage, the description fails to compensate, leaving parameter semantics unclear.

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 lists email threads by grouping on thread_id, returning one entry per thread with message count and latest date. This distinguishes it from sibling tools like search_emails (which returns individual emails) and get_email (specific email).

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 implies it is for listing threads, but does not explicitly state when to use it over alternatives like search_emails or get_email. No guidance on prerequisites or comparison to siblings.

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