mcp-whatsapp

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

The description adds valuable behavioral context beyond annotations: it specifies that the tool reads from a local cache and works offline, which is not covered by annotations like readOnlyHint or destructiveHint. It does not fully detail aspects like rate limits or exact return format, but provides meaningful operational insights.

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 extremely concise and front-loaded, consisting of a single, information-dense sentence. Every part ('reads local cache; works while disconnected', 'Search WhatsApp contacts by name or phone number') serves a clear purpose without any waste.

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?

Given the tool's low complexity (1 parameter, no output schema) and rich annotations, the description is largely complete. It covers key behavioral aspects like offline functionality, though it could slightly enhance completeness by mentioning the lack of output schema or result format.

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 100% schema description coverage, the input schema already fully documents the 'query' parameter. The description does not add additional semantic details about the parameter beyond implying it's used for matching names or phone numbers, so it meets the baseline without extra value.

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 specific action ('Search WhatsApp contacts'), resource ('contacts'), and scope ('by name or phone number'), distinguishing it from siblings like 'list_chats' or 'get_chat'. It precisely defines what the tool does without being vague or tautological.

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 provides clear context for usage ('reads local cache; works while disconnected'), which helps differentiate it from potential online search alternatives. However, it does not explicitly state when not to use it or name specific alternative tools, which prevents a score of 5.

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