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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true and destructiveHint=false; the description's 'Read-only' simply restates one of these. It adds no new behavior detail such as scope of results, pagination, or what 'across chats' actually spans, though at least it does not contradict the annotations.

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?

Three short fragments, front-loaded and free of padding, which is structurally sound. But the terseness tips into under-specification rather than efficient communication for a tool with undocumented parameters.

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?

With 0% schema coverage, no output schema, and a nested 'extra' object, the description would need to explain argument semantics and result shape. It explains neither, so an agent knows roughly what the tool is but not how to call it correctly.

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% across two parameters (account_id and a generic 'extra' object), so the description carries the full burden and fails to. Worse, it points at a 'query string' that is not visible in the schema, leaving the agent to guess whether that lives inside 'extra' and how account_id scopes the call.

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 names the resource ('Messages across chats') and the tool name supplies the verb, so the general purpose is discernible. However, it does nothing to separate this from very similar siblings such as list_messaging_messages or list_attendee_messages, so an agent cannot tell which list it wants without opening schemas.

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?

'Filter with the query string' is the only usage hint, and it describes how to narrow results rather than when this tool is the right pick over alternatives. There are no conditions, prerequisites, or named alternatives.

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