Convert a local AVIF still image

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

Annotations cover the safety profile (readOnly=false, destructive=false, openWorld=false), and the description adds context they can't: an environment precondition (local browser), a fidelity disclosure ('Source metadata is omitted; color, HDR and precision may change'), and a verification behavior ('compares every output pixel'). It does not say what happens if output_path already exists, which matters for a write tool.

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?

Four dense sentences, front-loaded with the core action before constraints and caveats. Some phrasing is jargon-heavy ('admitted reduced-header AV1', 'unsupported derived layouts') and costs the reader without adding precision, but nothing is padded.

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 4-parameter conversion tool with no output schema, the description covers inputs, refusals, fidelity trade-offs, and the runtime prerequisite. Gaps are the undocumented 'quality' parameter and the lack of any statement about return values or output-file overwrite behavior.

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 only 50% — input_path/output_path are documented, but 'format' and 'quality' have no descriptions. The description partially compensates by naming the three target formats, mapping loosely to the format enum, but it never mentions 'quality' or what it governs, so one of four parameters is unexplained in both schema and prose.

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?

Opens with a specific verb + resource + outputs: 'Convert one admitted reduced-header AV1 still AVIF to a new PNG, JPEG or WebP', which tells an agent exactly what goes in and comes out. It narrows scope with 'Refuses animation, movie tracks and unsupported derived layouts'. It never names the obvious sibling (abox_image_convert / abox_heic_convert), so differentiation from alternatives is left implicit.

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?

Gives clear eligibility conditions and explicit exclusions: still images only, animation and movie tracks refused, and a hard precondition 'Requires a local browser'. What's missing is routing guidance — it does not say to use abox_image_convert for other formats or abox_video_* for animations, so the agent must infer the alternative.

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