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

With no annotations, the description carries the full burden. It discloses the content of the returned messages (browser actions, reasoning, results) and the pagination behavior, which is genuine value, but it omits read-only semantics, ordering guarantees, and any auth or rate-limit context.

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 tight sentences with the purpose front-loaded and the pagination hint last; nothing is redundant. It stops just short of being maximally efficient.

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 tool with no annotations and no output schema, the description covers the essential ground: what is returned and how to page through it. It could say more about message ordering or the response shape, but the core agent needs are met.

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 100%, so all three parameters are already documented in the schema, making 3 the baseline. The description reinforces the cursor-based polling use of after= but adds no syntax or format detail beyond what the schema states.

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 states a specific verb+resource (get agent messages/steps for a session) and adds substance by naming what the messages contain: browser actions, reasoning, results. It does not explicitly differentiate itself from the sibling get_session, so it falls short of a 5.

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?

It gives clear operational context: use the after= parameter to poll for new messages since your last check. That tells the agent the intended polling workflow, but there are no stated exclusions or explicit comparisons to alternatives like get_session.

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