search_mail

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

Annotations already cover readOnly, idempotent, and non-destructive hints. The description adds meaningful behavioral context: results are untrusted data and local_index may be empty if the index isn't built. These go beyond annotations and aid the agent.

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 dense but efficient, front-loading the core purpose and then detailing the response structure and edge case. All sentences carry information, though the first sentence is long. It's appropriately sized for the complexity.

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 no output schema, the description explains the response structure (provider and local_index) and the empty-index scenario. It also flags untrusted data. It doesn't explicitly mention that 'top' limits results per source, but the schema covers that. Reasonably complete for a search tool.

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 input schema has 100% coverage with descriptions for all three parameters. The tool description does not add parameter-specific guidance beyond what the schema already provides, so the baseline 3 applies.

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?

States a specific verb (Search) and resource (mailbox), and describes the dual result structure (provider + local_index). It doesn't explicitly name a sibling it is not, but the purpose is clear and distinct from listing tools like list_messages. Not a 5 because it doesn't reference any alternative.

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 explains the two search sources and notes when local_index is empty, but it never states when to use this tool versus siblings like list_messages or list_unread. The usage is implied rather than explicitly guided.

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