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

With no annotations, the description carries the full burden. It usefully discloses the idle-status precondition, but says nothing about what happens if the precondition is violated, whether the call blocks until the task finishes, or how the session state changes afterward (the keep_alive parameter's effect is left entirely to the schema).

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 sentences, front-loaded with the action and immediately followed by the precondition. The final sentence is slightly redundant with the 'follow-up' framing but still earns its place by naming the reuse-of-context rationale.

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 and no output schema, the description covers purpose and precondition but omits return/result behavior and error handling. An agent can call it, but cannot predict whether the response is immediate or asynchronous.

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 100%, so all four parameters (task, keep_alive, session_id, output_schema) are already documented in the schema, and the description adds no format or constraint details beyond it. Baseline 3 applies when the schema does the heavy lifting.

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 and resource: 'Send a follow-up task to an existing keep-alive session.' It implicitly separates itself from run_session by emphasizing 'follow-up' on an existing session rather than starting a new one, though it never names the sibling explicitly.

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 a concrete precondition ('The session must be in idle status') and a clear use case ('multi-turn interactions where you want to reuse the same browser context'). It stops short of naming run_session as the alternative for starting fresh or stating what to do when the session is not idle.

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