mcp-whatsapp

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

Annotations already indicate this is a destructive, non-idempotent, open-world operation, but the description adds valuable context about the backfill behavior and timestamp anchoring logic. It doesn't contradict annotations and provides meaningful behavioral details about what 'backfill' means operationally, though it could mention potential rate limits or WhatsApp API constraints.

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 perfectly concise with just two sentences that efficiently communicate the tool's purpose and key parameter behavior. Every word earns its place, and the information is front-loaded with no unnecessary elaboration or repetition.

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 destructive tool with no output schema, the description provides adequate context about the operation's purpose and parameter behavior. However, it could better address what 'backfill' entails operationally (e.g., whether it's asynchronous, how long it takes, what data gets retrieved) given the destructive nature indicated by annotations.

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 both parameters. The description adds marginal value by explaining the default behavior when from_timestamp is omitted (anchoring on newest cached message), but doesn't provide additional semantic context beyond what's in the schema descriptions for chat_jid and from_timestamp.

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 ('Ask WhatsApp to backfill history') and target resource ('for a chat'), distinguishing it from all sibling tools which focus on messaging, group management, or contact operations rather than data synchronization. It precisely defines the tool's unique function in the WhatsApp toolset.

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 about when to use the tool (to backfill chat history) and includes conditional logic for the from_timestamp parameter, but doesn't explicitly state when NOT to use it or mention alternatives like list_messages for retrieving existing cached messages. The guidance is helpful but lacks explicit exclusion criteria.

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