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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the description only needs to add what they don't cover. It does add a meaningful trait — matching is literal word matching, not semantic — plus a fallback strategy, though it stays silent on case sensitivity, which fields (subject vs body) are searched, and result limits.

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?

Two short sentences, zero filler. The purpose is front-loaded and the caveat about literal matching follows immediately after, so an agent can decide in one read.

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 an output schema present, return values need not be described, and full annotations cover the safety profile. For a one-parameter search tool this is nearly complete; only ordering/pagination behavior for the result set is left unaddressed.

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?

There is a single parameter with 100% schema description coverage, so the schema already explains 'query'. The description adds no syntax detail beyond it — nothing about multi-word queries, phrase quoting, or operator support — so the baseline of 3 is appropriate.

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) plus resource and scope (the user's inbox drafts) in the first clause, which cleanly separates it from list_recent_drafts, get_draft, and count_drafts. The keyword-vs-meaning sentence further pins down the retrieval semantics of this tool versus its similarly named siblings.

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 tells the agent what to do when results are empty ('try another wording'), which is a useful operational hint, but it never states when to prefer this search over list_recent_drafts or get_draft. Usage is implied by the verb rather than explicitly scoped against alternatives.

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