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

Without annotations, the description discloses key behaviors: long-polling (`wait` parameter), cursor-based pagination (`since`), and return value (messages + cursor). It does not mention side effects or auth requirements, but as a read-only poll, this is adequate.

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?

Two sentences, no wasted words. First sentence states the purpose clearly; the second explains parameters and return value. Well-structured and front-loaded.

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?

The description covers input parameters and behavior. Since an output schema exists, return values are likely well-defined in the schema. The description is complete enough for correct usage.

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 coverage is 0%, but the description fully explains both parameters: `since` as a cursor for pagination and `wait` as a timeout for long-polling. This adds meaning beyond the schema's property names and defaults.

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 tool's purpose: 'Pull inbound WhatsApp messages the human sent to pingwa'. It specifies the use case (out-of-band instructions or late answers to an `ask`) and distinguishes from siblings like `ask` (sending questions) and `notify` (outbound messages).

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 explains when to use this tool (for inbound messages, especially late answers to `ask`) and how the parameters work. It does not explicitly state when not to use it, but the context provided is sufficient for an agent to recognize appropriate usage scenarios.

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