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

With no annotations, the description carries the behavioral disclosure burden. It explains the clean shutdown behavior, the valid moov atom guarantee, and the exact return fields. It does not mention failure modes or idempotency, but the core runtime behavior is well disclosed.

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 concise sentences with no wasted words. The action and key outcome are front-loaded, and the return values are listed compactly.

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 one-parameter tool with no output schema, the description is largely complete: it covers the operation, the expected input, and the return payload. It could mention edge cases like calling stop without an active recording, but the current information is sufficient for correct invocation in the normal flow.

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% and the single parameter already has a clear description: 'recordingId returned by device_record_start.' The tool description reinforces this pairing but does not add additional parameter-level detail. Baseline 3 is appropriate since the schema handles the semantics.

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 uses a specific verb and resource: 'Stop a screen recording started by device_record_start.' It also distinguishes itself by naming its paired start tool and detailing the clean remux pipeline closure. This leaves no ambiguity about what the tool does.

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 clearly indicates this tool is the counterpart to device_record_start, so an agent knows when to invoke it. It does not explicitly list alternatives to avoid, but the pairing and the device-specific naming make the intended usage obvious.

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