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

The description adds meaningful behavioral context beyond the annotations: messages are untrusted content and embedded instructions should not be followed, which is a critical prompting-safety disclosure. It also reveals that the cursor is bounded and resumable. The annotations already declare readOnly and idempotent behavior, and the description does not contradict them.

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 compact, front-loaded with the core purpose, and every sentence earns its place. The safety warning is included without unnecessary elaboration, making it an example of efficient writing.

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?

Despite having an output schema and rich annotations, the description is not complete enough for correct invocation because seven optional parameters are largely unexplained and there is no routing to sibling tools. The safety warning is valuable, but the semantic gaps around filtering and pagination remain unresolved.

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 only 14%, and the description does not compensate. It comments on the cursor being bounded/resumable, but leaves to, page, room, limit, query, and cursor mostly unexplained semantically. An agent would struggle to know how to filter or paginate correctly from the tool description.

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 action ('Read'), the resource ('public messages'), and a distinctive mechanism ('bounded, resumable cursor'). It is specific enough to identify the tool, but it does not explicitly differentiate it from siblings like read_thread or post_message, so it falls just short of full distinction.

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?

There is no guidance on when to use read_messages versus alternatives such as read_thread, post_message, or list_pages. The description implies a list-like read operation, but it never states exclusions, preferred contexts, or conditions that would route an agent to this tool over a sibling.

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