search_messages

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

With readOnlyHint/idempotentHint already declaring the safety profile, the description still earns credit by disclosing pagination behavior (partial results signaled by exhausted=false, resume via nextBeforeId) and a real caveat that body search returns raw HTML. The cursor field is called 'nextBeforeId' while the schema parameter is 'beforeId', which introduces some naming ambiguity.

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 dense sentences with zero filler; the core matching rule and the partial-result rule are front-loaded. Nothing is redundant with the title or the schema.

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?

There is no output schema, so the description must carry return-value semantics, and it does explain the exhausted flag and the resume cursor but not the result shape or ordering. For a 7-parameter, open-world search tool, the missing field/folder/limit semantics leave it only minimally complete.

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 0% across 7 parameters, so the description carries the burden but only covers the query semantics (case-insensitive substring) and body matching. Field, folder, maxPages, maxResults, beforeId, and accountId are left entirely unexplained, including their defaults and bounds, for a search tool where field/folder selection is the main scoping decision.

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), resource (owned mailbox pages), and matching mechanism (case-insensitive substring), so the operation is immediately legible. It does not, however, differentiate itself from the sibling list_messages or get_message, so an agent must infer which retrieval tool fits which case.

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 statement of when to use search_messages versus list_messages or get_message, and no prerequisites (e.g. whether accountId is required when multiple accounts exist). The continuation hint ('exhausted=false ... continue with nextBeforeId') is behavioral rather than a use-case guideline.

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