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

Annotations already declare readOnlyHint=true, idempotentHint=true, etc. The description adds value by listing the exact metadata fields returned, which helps the agent understand the output. It does not contradict annotations, and although it doesn't discuss errors or authentication, it provides useful context beyond structured data.

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, front-loaded sentence with no redundancy. It lists essential details efficiently, achieving maximum clarity with zero wasted words.

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 metadata tool with two parameters and no output schema, the description adequately covers purpose, required input, and returned fields. It omits the optional 'account' parameter and does not discuss edge cases (e.g., invalid chat_jid), but given the tool's simplicity, it is sufficiently complete.

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% because description only mentions chat_jid ('Requires chat_jid'), which is already marked required in schema. It adds no format or meaning, and completely ignores the optional 'account' parameter. Thus, it adds minimal value beyond the schema.

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 'Get metadata for a single chat' and enumerates specific fields (subject/name, archive/pin/mute state, unread count, timestamps). This distinguishes it from siblings like whatsapp_chats (listing) and mutation tools (archive/mute/pin).

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 use for a single chat, contrasting with whatsapp_chats for listing, but does not explicitly mention alternatives or when not to use. It provides the prerequisite of chat_jid, giving clear context, though no explicit exclusions or alternative tool references.

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