view_moment

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 disclose the key behavioral trait: the output is a still-image contact sheet of frames with exact timestamps, not playback, and the source is a file on disk. It does not mention decoding cost, latency, or failure behavior for a missing/invalid path, which are the remaining gaps.

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: the first front-loads what the tool returns, the second front-loads the usage trigger. No filler, no restatement of the tool name, and the most decision-relevant fact (returns an image) comes first.

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 simple frame-extraction tool with 100% schema coverage and no output schema, the description supplies what the schema cannot: the return format and the workflow position. Only minor items are absent (cost/performance, error cases), so it is nearly but not fully complete.

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 all five parameters (path, start, end, width, frames) are already documented with units and bounds. The description only restates the seconds-based start/end semantics that the schema already provides, adding no new meaning. Baseline 3 is correct when the schema does the heavy lifting.

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 ('Close look at one section of a video file on disk') with scope (start/end in seconds) and the concrete return type (an IMAGE of frames with exact timestamps). It is clearly distinguishable from view_clip and view_timeline, which are named/implied as different granularities.

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 positions itself in a workflow: 'Use after view_clip to find the precise best moment or cut point.' That tells the agent when to reach for it and which sibling precedes it. It stops short of stating when NOT to use it (e.g., whole-clip overviews belong to view_clip), so not a full 5.

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