Search contacts

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

Annotations already carry readOnly/openWorld/idempotent hints, so the description's job is lighter. It adds useful privacy context by stating it does not expose passwords or query an external address-book API, and it clarifies the data source (recent mail headers). 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?

Two sentences, front-loaded with the core action and resource, followed by a meaningful privacy qualifier. No redundant or filler language.

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?

For a read-only search with all parameters optional and sensible defaults, the description is usable as-is. However, with no output schema and undocumented query/limit/accountId semantics, an agent still lacks detail about return shape and parameter interaction, so it is 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?

The schema has 0% description coverage, so the description must compensate. It only implies the accountScope meaning ('one account or across all accounts'); it does not clarify query matching behavior, limit bounds, or how accountId selects an account. An agent has to rely on name/defaults/schema constraints.

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 names a specific verb ('search') and resource ('correspondents collected from recent mail headers'), and clarifies the scope ('one account or across all accounts'). It distinguishes this from generic search/mail_search by focusing on contacts from mail headers and explicitly ruling out an external address-book API.

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?

It clearly states the tool's use case — searching correspondents in one or all accounts — which helps an agent choose it over message-search siblings. It does not explicitly mention alternatives or when not to use it, but the 'correspondents from recent mail headers' scoping makes the boundary reasonably clear.

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