compress

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

With no annotations, the description must carry the behavioral burden. It discloses the key traits: this transcodes (hence lossy, quality-affecting) via a CRF ladder and returns the output path, but it says nothing about overwrite/destructive behavior, failure modes (e.g., existing file at output when overwrite=false), or that the operation is potentially long-running.

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 short sentences with no filler: the transformation and its knobs come first, and the return value is stated last. Every clause earns its place.

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 correctly states what is returned (the output path). Parameter docs are complete in the schema. The remaining gap is operational context — whether re-encoding loses quality irrecoverably and what happens on path collisions — which would be valuable for a write-producing media tool.

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 are already documented with defaults, enum values, and constraints. The description only echoes this at a high level ('CRF quality ladder', 'optional width cap') without adding new syntax, ranges, or interaction rules beyond the 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?

States a specific verb and resource ('Re-encode a video to a smaller file') plus the mechanism (CRF quality ladder, width cap). It is clearly distinguishable in intent from siblings like convert, scale, or export_preset, though it never names them explicitly.

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?

There is no guidance on when to pick this over convert, export_preset, or scale, despite a dense sibling set that overlaps heavily. The user must infer from the name and 'smaller file' phrasing that this is the size-reduction tool rather than a generic format conversion.

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