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

Annotations already declare destructiveHint=true, idempotentHint=false and readOnlyHint=false, and the description usefully adds that recordings should be short and bounded. However, it never explains the destructive dimension the annotation flags -- e.g. whether writing to an existing destination overwrites it -- nor any permission requirements. With annotations carrying the safety profile, this is adequate but not rich.

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?

Two sentences, zero waste, and the primary use condition is front-loaded ahead of the cheaper alternative. Nothing is repeated from the schema or annotations.

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?

Output schema exists so return values need not be described, and the schema covers all four parameters. The one remaining gap is that a destructiveHint=true capture tool never tells the agent what happens to an existing file at destination, which matters for safe invocation.

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%, with fps, duration_seconds, device and destination all documented including format guidance (.webm vs .mp4 per backend). The description adds no parameter-level meaning, so the baseline 3 applies.

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 names a specific action (short bounded screen recording) and the exact condition that motivates it (motion/timing needed to diagnose a UI issue). It clearly separates itself from the static-capture siblings take_screenshot and screenshot_region.

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 an explicit when-to-use rule plus an explicit alternative with a reason: prefer screenshot_region for static visual verification because it is cheaper and easier to inspect. That is exactly the routing guidance an agent needs.

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