mcp-whatsapp

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

Annotations indicate destructiveHint=true and idempotentHint=false, which the description aligns with by describing a state-changing action ('mark as read') that likely isn't idempotent. The description adds context beyond annotations by specifying it affects 'recent incoming messages' and has a practical effect ('clear the phone's unread badge'), enhancing behavioral understanding without contradiction.

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, well-structured sentence that efficiently conveys the tool's purpose and effect without unnecessary words. It is front-loaded with the core action and resource, making it easy to understand quickly.

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 (state mutation with two parameters), rich annotations, and 100% schema coverage, the description is mostly complete. It lacks output schema, but the description sufficiently explains the action and effect. Minor gaps include not detailing error cases or side effects beyond the badge clearing.

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 100%, so the schema fully documents parameters. The description does not add meaning beyond the schema, as it doesn't explain parameter usage or constraints. Baseline 3 is appropriate since the schema handles parameter documentation effectively.

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 ('Mark recent incoming messages in a chat as read') and resource ('chat'), distinguishing it from the sibling tool 'mark_read' which lacks the 'recent incoming messages' specificity. It explains the practical effect ('clear the phone's unread badge for that chat'), making the purpose unambiguous.

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 implies usage context by specifying 'recent incoming messages' and the effect on 'unread badge,' but does not explicitly state when to use this tool versus alternatives like 'mark_read' or other messaging tools. It provides clear intent but lacks explicit comparison or exclusion guidance.

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