capture_frames

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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false), so the bar is lower; the description adds real value beyond them by disclosing output location (screenshots/sequence-<time>/), the return value (an ffmpeg command), and the virtualised-time guarantee. It does not address disk-write side effects, which slightly tempers the score.

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?

Front-loads the [INSPECT] Read-only tag, then delivers purpose, behavioral guarantee, output location, and return value in three tight sentences with no filler.

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 by naming the saved images and the ffmpeg command. Combined with destination and timing behavior, an agent has enough to invoke it correctly, though file naming/counting specifics are left implicit.

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 fps, width, height, format, and duration are all documented in the schema, including the png/jpeg distinction. The description adds no parameter-level meaning beyond that, so the baseline of 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?

States a specific verb and resource ("Record a frame sequence for a video") and tags the tool as [INSPECT] Read-only, making its inspection role clear. It distinguishes itself from single-frame siblings like take_screenshot by emphasizing a frame sequence, but never names an alternative 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?

Usage is implied rather than stated: the agent can infer this is for capturing video frames rather than a still, and the note about virtualised time hints at when smooth, deterministic output matters. There is no explicit when-to-use/when-not or named alternative such as take_screenshot.

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