Read WhatsApp chat messages

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

The description adds meaningful behavioral context beyond the readOnlyHint annotation: messages come from the local inbox log, are returned oldest first, and the tool works even when WhatsApp is unreachable. This is substantial, decision-relevant behavior that the agent could not infer from the schema or annotations alone.

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 two concise sentences with no filler. The key operation and scope are front-loaded, and the behavioral caveat about the local log follows immediately.

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 simple read-only tool with fully covered parameters, a readOnlyHint annotation, and no output schema, the description provides all essential context: what is read, from where, the ordering, and the offline capability. No critical information 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 coverage is 100%, so the baseline is 3, but the description adds value by clarifying that 'limit' means the last N messages and that output is ordered oldest first. This refines the semantics beyond the schema's simple 'Max messages, default 30' 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 uses a specific verb and resource: 'Reads the last N stored messages for one allowlisted chat, oldest first.' It also distinguishes itself from live-fetch tools by explicitly stating the messages come from the local inbox log, not a live WhatsApp fetch.

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 gives clear context for when to use the tool: reading stored messages from the local log, and it explicitly notes this is not a live WhatsApp fetch, which implies it is not for live retrieval. It does not name sibling alternatives directly, but the behavioral distinction is enough.

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