Find chats and contacts by name or phone fragment

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

Annotations already provide readOnly, idempotent, and non-destructive hints. The description goes further by disclosing data-source limitations ('sync cache... may not be locally present'), input constraints ('query must be non-empty', limit clamping), and a safety note about user-authored content. This is substantial context beyond the structured 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?

Every sentence delivers distinct value: purpose, return fields, query constraint, limit behavior, and data-source caveat. The description is front-loaded with the most important information and contains 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, combined with rich annotations and an existing output schema, covers everything needed to invoke the tool correctly: search semantics, required-parameter behavior, limit bounds, source reliability, and safety considerations. There are no obvious gaps.

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?

With 0% schema description coverage, the description fully compensates by explaining that query is a name/phone substring, must be non-empty, and that limit has a default of 20 with a [1, 100] clamp. This gives an agent practical meaning for both parameters beyond their raw names and types.

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 a specific action ('Search') across a defined scope ('chat partners + address book') with an explicit matching criterion ('name/phone substring'). It distinguishes itself from sibling search_messages by focusing on contacts rather than message content.

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 makes clear what kind of search this tool performs and thereby implies the appropriate use case. It does not explicitly name alternative tools for when not to use it, but the object of search (contacts/address book) is unambiguous enough for an agent to route correctly.

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