list_emails

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

Annotations already declare readOnlyHint=true, and the description adds that it returns only 'metadata + snippet, no bodies' and supports pagination. This provides useful context beyond the annotation, though it could disclose rate limits or auth requirements.

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 three sentences long, front-loaded with the main purpose, then lists capabilities, and ends with an alternative. Every sentence adds value without redundancy.

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?

Given the tool's complexity (14 parameters, no output schema), the description covers the essential behavioral aspects (no bodies, pagination, filtering). It could be more complete by describing the response structure (e.g., fields returned) beyond mentioning metadata and snippet.

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?

With 57% schema description coverage, the description adds minimal meaning beyond the schema. It mentions filtering by 'folder, sender, unread, dates, etc.' but does not elaborate on syntax (e.g., date format, sender field name) that isn't already in the schema.

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 uses the specific verb 'list' with the resource 'emails', specifies scope ('connected mailbox'), and clarifies it returns 'metadata + snippet, no bodies'. It distinguishes from sibling tools by explicitly mentioning 'Use get_email for full bodies' and stating it's the primary way to check 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 clearly states when to use this tool ('to check the user's email', 'no browser needed') and provides a specific alternative ('Use get_email for full bodies'). It also mentions pagination with pageToken. However, it does not explicitly exclude scenarios where search_emails might be preferable.

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