transform

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

With no annotations to lean on, the description still carries real behavioral weight: it discloses that the operation re-encodes (a lossy, potentially slow, quality-affecting step), names the codecs, notes audio is retimed with speed changes, that crop applies before resize, and that the default output is name.transformed.ext rather than overwriting the input. The gap is safety semantics — overwrite and dry_run exist in the schema but the description never says what overwrite destroys or that dry_run previews without writing.

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-loaded with the one-sentence capability statement, then grouped by parameter with each rule compressed into a clause. No filler, no restatement of the tool name, and the units, ranges, and defaults that matter are all present in a very short block.

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?

The output schema means return values need no explanation, and the transformation semantics are well covered. But for a 9-parameter tool that writes a new media file, the description omits the flags an agent most needs to reason about safely (dry_run, overwrite, timeout_s) and says nothing about format inference from the output extension or failure conditions such as an existing target file.

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% across 9 parameters, so the description has to compensate and it only partially does. It richly explains width/height (aspect-ratio coupling), crop syntax ('W:H' centered vs 'W:H:X:Y'), speed range and semantics (0.25-4, 2 = twice as fast), and output naming, but input, output as an explicit parameter, dry_run, overwrite, and timeout_s are left entirely to the bare schema titles.

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 opening line gives a specific verb set and resource: 'Resize, crop and/or change the speed of a video'. That operation set is distinct from every sibling (convert, compress, trim, make_gif, extract_audio), so an agent can route to it without opening the schema, and the parenthetical about H.264/AAC vs VP9 adds useful precision about what re-encoding implies.

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 is effectively a parameter primer ('give one and the other keeps the aspect ratio', 'applied before resizing') rather than usage routing. It never says when to choose transform over compress (which also shrinks output) or convert, and offers no exclusions or preconditions such as requiring a valid video input. Usage is implied by the operation list, not stated.

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