search_mail

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

With no annotations, the description effectively discloses behavioral traits: filters are ANDed case-insensitive substring matches, date format, performance impact for large folders, and return type (summaries with opaque id). Minor omission: error handling for missing folders or no results.

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 concise (~80 words) and well-structured: one-line purpose, filter details, date format, account behavior, return type, and performance advice. No unnecessary words; every sentence adds value.

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?

Given 10 optional parameters and no output schema, the description covers core behavior, filter logic, and performance notes. It explains return type (summaries with opaque id) which compensates for missing output schema. Could mention pagination or result ordering.

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?

Despite 0% schema description coverage, the description adds meaning for key parameters (since/before take ISO dates, limit defaults, account defaults to all accounts, folder defaults to INBOX). It explains filter behavior (ANDed substring match) that applies to all text parameters. Could be more explicit about each parameter's purpose.

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 clearly states the tool searches a folder's mbox, explains it searches across accounts and returns summaries with an opaque id. It distinguishes from siblings like list_accounts and read_message by focusing on search functionality.

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 provides guidance on when to use (searching mail), mentions performance considerations and suggests narrowing with account and limit. It implies alternatives like read_message for full content via 'opaque id for read/extract', but lacks explicit when-not-to-use statements.

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