ae_capture_frames

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

With no annotations, the description carries the full burden and it does well: 'Changes nothing' explicitly declares a non-mutating read operation, and it describes the artifact produced (grid with time labels). It omits any mention of permissions, size/time cost of rendering, or failure modes for an invalid comp/time range.

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 tight sentences: what it produces and why first, then how to specify times, then the safety note. No filler, and the most decision-relevant information is front-loaded.

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?

There is no output schema, and the description compensates by describing the return artifact as a single contact-sheet image with time labels. Combined with 100% schema coverage on all 9 parameters, an agent has enough to call it correctly; only edge-case behavior (conflicting time arguments, render failures) is unaddressed.

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 baseline is 3, but the description adds real semantic value the schema doesn't: the three mutually exclusive ways to pick frames (explicit times, start/end with count, or step) and the default of 9 evenly spaced. It does not explain interaction rules (e.g., what happens if times and count are both supplied).

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: renders several frames into ONE contact-sheet image with a grid and time labels. The singular sibling ae_capture_frame is implicitly distinguished by 'several frames ... into ONE contact-sheet image', so an agent can tell the two apart without opening a 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?

Gives a clear use context ('to judge an animation: timing, easing, overlaps, elements appearing outside their containers'), which is exactly the decision the agent needs. It stops short of naming ae_capture_frame or ae_render_preview as alternatives for single-frame or motion-clip inspection, so no explicit when-not guidance.

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