list_emails

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

With no annotations, the description must carry the full burden, and it does disclose two useful traits: results are compact metadata rather than full messages, and the default scope is the inbox. It omits read-only nature, whether spam/trash are included, the 50-item cap, and pagination behavior beyond what the page_token field already implies.

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, no filler, and the core purpose is front-loaded before scope and query syntax details.

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 list tool with no output schema and no annotations, the agent still lacks knowledge of what fields 'compact metadata' contains and what max_results defaults to. The essentials for invocation are present, but return-shape and limit details are thin.

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 coverage is 67%: query and page_token are documented in the schema, while max_results has no description anywhere. The description's note about Gmail search syntax and the inbox default adds modest meaning beyond the schema's own example, so the baseline 3 fits.

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 ('List personal Gmail messages') and adds scope detail ('Defaults to the inbox', 'compact metadata') that separates it from siblings like read_email and list_drafts. It stops short of explicitly naming those alternatives, so an agent must infer the routing.

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 says to use Gmail search syntax in the query and that the default scope is the inbox, which implies when to use it. There is no explicit when-not guidance or reference to read_email/read_thread/list_drafts for different needs, so the agent is left to infer boundaries.

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