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

The annotations already flag readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable non-obvious context: it relies on Wacli, an unofficial client, and warns that accounts may be restricted for ToS violations. This is exactly the kind of behavioral disclosure annotations do not provide.

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 compact sentences with no filler. The first front-loads the action and prerequisite, and the second adds a necessary risk warning. Every word earns its place.

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 read-only, two-parameter tool with a fully documented schema and an output schema, the description is complete. It covers the key prerequisite, the safety profile via annotations, and adds an important risk warning. Nothing needed for 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%, with chat_id and limit already documented, including the chat_id source and default limit. The description restates the chat_id provenance but adds no meaningful parameter semantics beyond what the schema already provides, so the baseline of 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 action and resource: reads messages from a specific WhatsApp chat, and identifies the required chat_id source. The WhatsApp qualifier clearly distinguishes it from sibling tools like read_messages, signal_read_messages, and teams_read_chat_messages without needing to inspect the schema.

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?

Provides a concrete prerequisite: chat_id must come from a previous whatsapp_list_chats call. This gives clear context for when this tool applies, though it does not explicitly name exclusions or alternatives such as using whatsapp_search_messages for cross-chat search.

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