whatsapp_search_contacts

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

With no annotations, the description must carry the full burden of disclosing behavior. 'Searches' implies a read-only operation, but it does not mention prerequisites (e.g., syncing via whatsapp_sync), potential staleness of synced metadata, or what the return value looks like. This is minimal disclosure.

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 description is a single sentence but is truncated mid-phrase ('to their J...'), making it incomplete. It is not well-structured because the essential point is cut off, and the reader is left with an unfinished thought.

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 fails to explain how to use the tool given the empty parameter schema, what it returns (no output schema), or any preconditions like syncing contacts. The truncation exacerbates the incompleteness, leaving critical information missing for an agent to invoke the tool correctly.

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 input schema has zero parameters, but the description claims the tool searches 'by name or number', suggesting the agent can specify these fields. This is a direct contradiction between the description and the schema, leaving the agent unable to provide the necessary input. The description adds misleading meaning rather than clarifying the empty schema.

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 the action ('Searches your WhatsApp contacts') and the resource, and specifies the search criteria ('by name or number'). It also provides a use case ('use it to resolve a person to their J...'). However, the sentence is truncated, cutting off the exact purpose, and the empty parameter schema contradicts the implied input, preventing a higher score.

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 gives a clear usage context: 'use it to resolve a person to their J...' This tells the agent when to apply the tool. It does not mention alternatives or exclusions, but the context is sufficiently specific for most scenarios.

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