session_observe

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states what is returned (URL and aria-snapshot) but doesn't clarify whether this is a passive read operation or whether it might alter session state. For an observation tool, the read-only nature is implied by the name but never explicitly stated given annotations are absent.

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, efficient sentence with zero wasted words. It front-loads the action ('Return') and specifies both outputs clearly. The terseness is appropriate for a simple observation tool, though a touch more context about the aria-snapshot format could justify extending it.

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 no annotations, no output schema, and zero schema description coverage, the description is thin. It names two outputs (URL and aria-snapshot) but doesn't describe the format of the aria-snapshot, whether both always come together, or what happens if the session is inactive/invalid. Given siblings include session_act (which presumably mutates), this read tool would benefit from clarifying its non-mutating role.

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?

The single parameter `session_id` is a plain string with no schema description coverage (0%). The tool description doesn't mention this parameter at all, so the agent must infer that session_id refers to a session previously created by session_start. Since all sibling tools likely use the same session_id pattern, some inference is possible, but the description provides zero compensation for the documented schema gap.

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 tool returns the current URL and aria-snapshot of the session's page. It uses a specific verb ('Return') with a clear resource ('current URL and aria-snapshot'). While it doesn't explicitly differentiate from siblings, the 'observe' name and description of returning page state clearly distinguish it from session_start (initialize), session_act (perform action), session_end (terminate), and qa_get_trace.

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 provides no guidance on when to use this tool vs alternatives. It doesn't state this is the read/inspection tool for a session's current state, nor does it mention any prerequisites (e.g., session must be active, started via session_start). There's no context about typical usage patterns such as observing before deciding an action.

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