search_contacts

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

No annotations are provided, so the description carries the full burden, and it discloses almost nothing behavioral: no statement on partial vs exact matching, case sensitivity, result limits, or ordering. That 'search' is non-destructive is inferable from the verb but not stated, and nothing warns about ambiguous matches.

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 core sentence is front-loaded and unambiguous, and the Args block is short enough not to waste space. Slight redundancy in restating the parameter name, but every line adds a bit of meaning.

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 one-parameter read tool with an output schema, the basics are covered, so return values need no explanation. What is missing is search-specific behavior: whether multiple contacts can come back, how results are ordered, and what an empty result looks like.

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 0% (the property has only the title 'Query'), so the description must compensate, and it does by defining the term as matching against contact names or phone numbers. It still omits match semantics (substring, prefix, normalized phone format), which is the one thing an agent would most need.

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 (search) and resource (WhatsApp contacts) plus the matching keys (name or phone number), which distinguishes it from get_contact in the sibling list. It stops short of explicitly naming that sibling or noting that results may be multiple.

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?

Usage is only implied: an agent can infer this is the lookup path when it lacks a contact ID, versus get_contact for direct retrieval. There is no explicit 'use this when / use X instead' routing, no mention of what happens when no match is found.

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