record_video

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

Annotations only declare readOnly=false, destructive=false, openWorld=false; the description adds substantial context beyond that: a 100 MB clip cap, that the scratch-directory file is deleted at session stop, that audio requires a session started with audio, and that the result is frames-as-one-image the agent cannot play. These are exactly the operational limits an agent needs and none are recoverable from structured fields.

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?

Purpose and output contract are front-loaded in the first two sentences, and each subsequent clause carries distinct information (size cap, audio requirement, stopping modes, cheaper alternative). The colon-chained, run-on phrasing makes it denser than ideal, but there is little filler to cut.

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?

With no output schema, the description carries the return-value burden and does so fully: saved path, clip duration, up to 8 timestamped frames returned as one image, and the until_line case yielding the matching line. Combined with the size cap and file-lifetime note, an agent has everything needed to call and interpret this tool.

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%, so the schema already documents all 9 parameters and the baseline is 3. The description still adds cross-parameter meaning the schema does not: seconds is a maximum when until_line is present, until_line's result reports the matching line, and sound only functions in an audio-enabled session.

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?

States a specific verb+resource (record a video of the screen or one window) and the artifact produced (.mp4), naming both save destinations (scratch directory vs. path). It also differentiates itself from siblings by name, citing record_audio and take_screenshot's burst. An agent can distinguish it from every other capture tool without opening the schema.

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?

Explicitly routes to alternatives: 'For a few moments of motion, take_screenshot's burst is cheaper' and 'sound also says what it heard, as record_audio does.' It also frames the until_line vs. seconds choice as two stopping modes. It stops short of stating when recording is inappropriate overall (e.g., headless/no-display sessions), so it is clear context rather than full when/when-not coverage.

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