mcp-whatsapp

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

Annotations indicate destructiveHint=true and openWorldHint=true, but the description adds valuable context: it specifies that the tool 'reads local cache' and 'works while disconnected,' clarifying its offline capability and data source. This goes beyond annotations, though it could mention potential side effects of destructiveHint (e.g., cache updates). 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?

The description is front-loaded with key information in a single, efficient sentence: it starts with the operational context, states the action and resource, and includes the parameter key. There is no wasted text, making it highly concise and well-structured.

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 moderate complexity (2 parameters, no output schema), the description covers purpose and behavioral context adequately. However, it lacks details on return values or error handling, which would be helpful since there's no output schema. It compensates somewhat with offline usage notes.

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 50%, with chat_jid well-documented in the schema but include_last_message lacking description. The description does not add meaning beyond the schema for parameters, as it only mentions 'by JID' without explaining include_last_message. Baseline 3 is appropriate given partial schema coverage and no compensation in the description.

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 ('Get WhatsApp chat metadata'), resource ('by JID'), and scope ('reads local cache; works while disconnected'), distinguishing it from siblings like list_chats or get_group_info. 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 when to use this tool ('reads local cache; works while disconnected'), which is useful for offline scenarios. However, it does not explicitly state when not to use it or name alternatives (e.g., list_chats for broader queries), leaving some guidance gaps.

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