session_observe

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

With no annotations, the description carries the full burden. It does not explicitly state that the operation is read-only, nor does it describe error behavior for invalid session IDs or inactive sessions. The word 'return' suggests non-mutation, but other behavioral aspects are undisclosed.

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 sentence with no unnecessary words. It is front-loaded with the verb and clearly states the output components, making it extremely concise and well-structured.

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 tool with one parameter and no output schema, the description adequately specifies the return value (URL and aria-snapshot). It does not detail the output format or error handling, but given the tool's simplicity, the description is nearly complete, with only minor missing context.

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%, so the description must compensate. It references 'session's page' which implies session_id identifies a session, but it does not explain what a session_id is, its format, or how to obtain it. This is minimal semantic addition beyond the raw parameter name.

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 'return' with a clear resource: 'current URL and aria-snapshot of the session's page.' This clearly differentiates it from sibling tools like session_start and session_act, which focus on lifecycle actions, and qa_get_trace, which retrieves traces.

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 the tool (to observe the page state) but does not explicitly state when not to use it or mention alternatives. It lacks guidance on prerequisites such as needing an active session, which is left to the user to infer.

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