Search Contacts

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

Annotations already declare readOnly, idempotent, and openWorld, but the description adds critical non-obvious behavior: a bounded, header-only scan of a recent mail window, message_count counting only within that window (not all-time), and results ordered 'most recent first.' 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?

Four sentences, each earning its place: purpose, behavioral caveat, return format, and parameter guidance. The core purpose is front-loaded with no redundancy.

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 and rich annotations, the description covers the remaining non-obvious semantics an agent needs—recent-window behavior, the meaning of message_count, and inbox_id omission—making the tool fully callable without further inference.

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%, so the baseline is 3. The description adds meaningful nuance by explicitly explaining that omitting inbox_id scans every accessible inbox, reinforcing but extending the schema's 'set it only when the user named a specific inbox' guidance.

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 and resource: 'Find people by name or email fragment.' It clearly distinguishes this tool from the email-centric siblings by describing contact search behavior and the 'no stored contact list' caveat, reinforcing what it is not.

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 clear context and a concrete usage rule: 'For general or cross-inbox questions ... OMIT inbox_id so every accessible inbox is scanned.' It does not name an alternative tool, but no contact-search sibling exists, so there is no alternative to exclude.

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