whatsapp_pin_message

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

Adds valuable context beyond annotations: everyone in the chat sees the pin (social/visibility behavior), and supports time-limited pinning. The success confirmation is stated. Annotations cover the safety profile (idempotent, non-destructive, open world), so remaining gaps are minor.

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?

Three tight sentences: action, visibility note, sibling routing, and return value. Front-loaded with the core action; zero 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?

For a 5-param mutation tool with full schema coverage and annotations covering safety, the description is nearly complete. It could explain unpin semantics or default pin duration, but nothing critical to correct invocation is missing.

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 already documents all five parameters (including pinned flag and pinExpiration format). The description only hints at 'optionally for a limited time,' adding little beyond what the schema provides. Baseline 3 applies.

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?

States a specific verb (pin/unpin), resource (message in a chat), and disambiguates from the near-identically-named sibling whatsapp_pin_chat by naming it directly. An agent can immediately distinguish the two.

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?

Explicitly routes the agent: 'To pin a whole chat in the list, use whatsapp_pin_chat.' This is exactly the alternative-selection guidance needed given the confusingly similar sibling name.

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