Search all mail

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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses the deduplication behavior (collapse duplicates by Message-ID) and that results report message locations. This adds meaningful behavioral context not present in the 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?

Extremely concise: two sentences that front-load the core function and then the usage context. Every word earns its place, with no filler.

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?

The description covers purpose and usage well, but given 8 parameters and no output schema, it leaves significant gaps. The lack of parameter descriptions for most fields and no detail on the result format beyond 'reporting where each message lives' makes it merely adequate, not fully 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 only 38%, leaving most parameters (from, text, subject, unread_only, flagged_only) undocumented. The description does not compensate by explaining any parameter semantics, so agents are left without help for these inputs.

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?

Purpose is clearly stated with a specific verb and resource: 'Search every mailbox at once'. It also describes the distinguishing behavior of collapsing duplicates by Message-ID and reporting locations, which sets it apart from sibling search_mail.

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?

Provides explicit usage guidance: 'Use when you do not know which folder something is in.' This gives clear context but does not explicitly name alternatives or exclusion cases, so it stops short of a 5.

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