Search emails

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

Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), so the description does not need to restate side effects. It adds valuable behavior beyond annotations: the tool searches 'local envelope data and full bodies' and sender filters are 'case-insensitive substring matches', which meaningfully shapes expectations. No contradiction with annotations.

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, compact sentence that front-loads the operation and scope and follows with a useful behavioral detail. Every word contributes; no filler or repetition of schema content.

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 all 11 parameters documented in the schema, an output schema present, and annotations covering side effects, the description adds the missing context an agent needs: local data scope and substring case-insensitivity. It would be stronger with explicit sibling routing, but that gap does not make the invocation unclear.

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 100%, which earns a baseline 3, but the description adds genuine param semantics by specifying that sender filters are case-insensitive substring matches. This clarifies intended behavior for from_addr and to_addr beyond the schema wording.

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 a specific verb ('Search') and identifies the resource ('local envelope data and full bodies'), making the operation clear. It does not explicitly contrast with sibling tools like get_email or list_recent, but the 'local' scope plus search semantics prevent major confusion.

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?

There is no guidance on when to use search_emails versus siblings such as get_email, get_emails_batch, or list_recent; no alternatives are named and no exclusion conditions are given. An agent must infer trigger conditions from the parameter list, which is insufficient for good tool selection.

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