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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds behavioral value by listing the concrete fields returned (duration, dimensions, frame rate, codecs, audio channels, rotation, size), which matters because no output schema exists. It stops short of stating failure behavior for unreadable or unsupported files.

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?

A single front-loaded sentence with the action first and the returned attributes enumerated after a colon. No filler, no redundant restatement of the title, and it is appropriately sized for a simple metadata reader.

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 read-only tool with no output schema, the description adequately covers what comes back by enumerating the metadata fields, and annotations cover the safety profile. Gaps remain around error conditions, supported formats, and how path interacts with deviceId/workSessionId scoping.

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 67%: deviceId and workSessionId are well documented in the schema, while 'path' has no description at all. The description adds no syntax or format detail for the required path argument, only the phrase 'on this Mac', so it does little beyond what the schema already provides.

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 (describe) and resource (video/audio file on this Mac) and enumerates exactly what is reported: duration, dimensions, frame rate, codecs, audio channels, rotation, size. That enumeration inherently separates it from siblings like video_frames, video_edit, and video_transcribe, which perform different actions on the same resource.

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?

The description implies the use case (inspect media metadata) but never states when to prefer this over video_frames or video_status, nor any prerequisites such as the file needing to exist locally. It notes 'on this Mac', which is a weak scoping hint, but there is no explicit when/when-not guidance.

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