matte_external

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

No annotations are provided, so the description carries the full burden. It usefully discloses that the binary is user-supplied/external and that a licence check gates execution, which are non-obvious behavioral facts. It says nothing about failure modes when the external tool is missing, output format, or runtime behaviour.

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, front-loaded with the action and no filler. The licence warning is effectively placed second as a caveat. Efficient, though extremely terse given the 0% schema coverage it is meant to offset.

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?

With no annotations, no output schema, and three wholly undocumented required parameters, an agent is left guessing at command_template syntax and what a run returns. The description covers the concept and one prerequisite but is not complete for a tool this unannotated.

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%, so the description must compensate. It does explain that {input} and {output} are placeholders substituted with the input/output paths, which gives those two parameters meaning the schema lacks. The third required parameter, command_template, is never explained — how to build it or what syntax is expected.

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 — run an external AI matting tool the user installed — with concrete examples (RVM, MatAnyone). The 'external/user-installed' framing distinguishes it reasonably from sibling tools like chroma_key, though it never names a sibling explicitly. An agent can tell what it does without opening the schema.

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 supplies one real prerequisite ('check that tool's licence first') and implies the placeholder convention for invocation. It does not say when this is preferable to chroma_key or other matting/keying siblings, nor when not to use it. Usage is implied rather than routed.

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