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

With no annotations, the description carries the full burden and does so well: it discloses hard input limits (25 MB / 20 min), duration cap for GIF/WebP (15 s), cost (€0.008 per minute), and the auth mechanism (API key in Authorization: Bearer). It does not describe failure modes, processing latency, or sync/async behavior, which keeps it from a 5.

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?

Capabilities, limits and pricing are front-loaded before the parameter list, and every clause carries information with no filler. It is dense and somewhat run-on as a single paragraph, but appropriate in size for an 11-parameter tool.

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 complex 11-parameter media tool, the description covers cost, size/duration limits, auth, formats and all parameter meanings, and an output schema exists so return values need not be explained. Only edge behavior such as error handling or processing time is absent.

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 0% and every parameter is a nullable string with no titles or meaning, so the description does the heavy lifting: it names all 11 parameters with units (start/end in seconds, width in px), enum values for aspect and format, defaults (mp4, fps 12, quality 75, crf 23), and valid ranges (1–100, 18–35). This fully compensates for the undocumented schema.

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?

The description states specific verbs and resource up front: trim by start/end, centre-crop to named aspect ratios, resize, mute, and lists concrete outputs (MP4, WebM, GIF/WebP, JPG frame, MP3). An agent can tell immediately this is a video clipping/transcoding tool and distinguish it from siblings like compress or subtitles.

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 through capabilities and limits ('clip up to 15 s', 'input up to 25 MB / 20 min'), so an agent can infer applicability, but there is no explicit when-to-use/when-not guidance or routing to alternatives such as compress or extract-audio tools elsewhere in the sibling list.

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