Manage a WhatsApp chat

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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the safety profile is covered. The description adds valuable context by noting that mark_read sends read receipts and that mute_hours defaults to 8, which are behavioral specifics not captured in the annotations. While not exhaustively detailing side effects for every action, it provides meaningful extra insight beyond the structured metadata.

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 a single, compact sentence that starts with the core verb 'Change the state of a chat' and immediately lists all supported actions. There is zero fluff, and every word adds value. For a tool with multiple enumerated actions, this is an optimally concise format.

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?

Given the tool's simplicity and the completeness of the schema (100% param coverage) and annotations, the description covers the essential information an agent needs to call it correctly. It does not mention return values, but there is no output schema, so that is not required. Minor gaps like behavior on already-archived chats or edge cases are not necessary for correct invocation.

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 all three parameters (action, chat_id, mute_hours) are already documented with descriptions and constraints. The description reiterates the mute_hours default (8) and notes 'only used by mute', but this duplicates schema information. It adds no new semantic meaning beyond the schema, so the baseline of 3 is appropriate.

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: 'Change the state of a chat' and enumerates the specific actions (archive/unarchive, pin/unpin, mute/unmute, mark_read/mark_unread). This is a specific verb+resource pairing that distinctly separates it from sibling tools like manage_group or send_message. The title 'Manage a WhatsApp chat' further reinforces the scope, making it easily distinguishable.

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 implies when to use this tool by listing the supported actions, so an agent can infer it handles any chat state change (archive, pin, mute, read status). It does not explicitly name alternatives or state when not to use it, but the action list is comprehensive and self-explanatory. Given that no sibling tool covers these specific operations, the context is clear enough.

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