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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable context about local-only data and pagination behavior, which goes beyond annotations. However, it doesn't detail the return format or error cases, but given the annotations, this is sufficient.

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 concise, front-loaded with the main purpose, and every sentence adds value. It efficiently covers usage, pagination, and related tools without fluff.

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 tool has 7 parameters and no output schema, but the description covers the essential usage and pagination. It references related tools for coverage and backfill, which helps the agent understand the broader context. It could mention the limit parameter or return format, but overall it's complete enough for a list operation.

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 0%, so the description must compensate. It explains the key parameters: chat_jid (required, from whatsapp_chats), before/after for pagination, and order for sorting. It doesn't explain limit, since, or account, but the core semantics are covered. Given the low schema coverage, this is a strong effort.

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 lists messages in a chat from local history, with a specific verb and resource. It distinguishes from siblings by noting it only returns locally synced messages and referencing related tools for coverage and backfill.

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 explains when to use this tool (list messages from local history), how to paginate (before/after with timestamps), and when not to use it (to see archive coverage or pull older messages, use whatsapp_history_coverage and whatsapp_history_backfill). This provides clear context and alternatives.

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