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

Annotations already include readOnlyHint=true and idempotentHint=true, which the description reinforces with 'Read-only: reports on the task without affecting it.' The description adds behavioral nuance by mentioning 'poll for completion' and 'detect guardrails,' which are not in the annotations. It does not contradict the annotations and adds useful context beyond what structured fields provide.

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 two sentences with no filler. It front-loads the core purpose and then adds the primary use cases and read-only nature. Every sentence contributes value, and it is appropriately sized for a simple polling tool.

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?

Given the presence of an output schema (which documents return values), the low complexity, and straightforward parameters, the description is complete. It covers the purpose, usage context, and read-only nature. An agent has everything needed to decide when to call this tool and what to expect.

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 input schema covers 100% of the parameters with descriptions for both taskId and sessionId. The tool description does not add any parameter-specific details beyond the schema, so the baseline score of 3 applies. It neither enhances nor detracts from the schema's clarity.

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 ('Check'), a clear resource ('status of a task'), and adds context ('previously started in a browser session'). It also signals the two main uses (poll for completion, detect guardrails), which clearly distinguishes it from action-oriented siblings like pause_session_task or stop_session_task. The purpose is unmistakable.

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 explicitly states when to use the tool: 'Use to poll for completion or detect guardrails.' It does not explicitly name alternatives or say when not to use it, but given the sibling list, no other tool serves this status-checking function. The guidance is clear enough for an agent to select this tool over mutating actions.

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