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

With no annotations, the description must carry the full burden of behavioral disclosure. It does mention that processing happens in the browser and notes credit usage, but it does not disclose how input/output is handled, whether originals are modified, file size/number limitations, or any side effects. This is insufficient for a tool that merges files.

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?

The first sentence is concise and front-loaded. However, the remaining 4-5 sentences are a verbose explanation of credits and day-pass restrictions, which could be condensed to 'uses credits; see pricing page.' Some of this commercial context is useful, but it is not tightly packed.

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 tool has no parameters, no output schema, and no explanation of how it receives input (e.g., ambient workspace files). It does not specify supported formats, number of videos, output destination, or behavior in error cases. For a simple tool the missing input/output mechanics leave a significant gap for an agent to invoke it correctly.

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?

The input schema has zero parameters, so schema coverage is vacuously 100%. With no parameters to document, the description need not add parameter details. The baseline for 0 parameters is 4, and the description does not introduce any misleading parameter information.

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 opens with 'Merge Videos — Combine multiple videos into one file,' which states a specific action (combine) and resource (videos) with an unambiguous result (one file). It is distinct from sibling tools like mio_video_converter or mio_video_compress, and no other video merge tool exists in the sibling list.

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 implies when to use the tool (when combining multiple videos into one file) and provides context that it runs in the Video And Audio Studio with higher credit consumption. However, it does not explicitly compare against alternatives or state exclusions for other video tools, and the credit/day-pass information is more about pricing than usage selection.

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