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

Annotations already indicate the operation is not read-only and not destructive. The description adds that the output is MP3 and that FFmpeg is used, but it does not disclose side effects, mixed-format handling, or output delivery behavior. This is a modest addition beyond annotations, not comprehensive.

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 description is a single, efficient sentence with the essential constraint front-loaded and a useful category tag. There is no filler or redundant explanation.

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 one-parameter tool with annotations and a fully descriptive schema, the description provides enough information to invoke the tool correctly. A note about output/return behavior or ordering would make it fully complete, but nothing critical is missing.

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 schema already documents the files parameter fully, including accepted formats and the at-least-2 constraint. The description only restates 'at least 2' and adds no new parameter-level semantics, so the baseline of 3 applies.

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 clearly identifies the operation (merge/concatenate), the resource (multiple audio files), the minimum count (at least 2), and the output format (one MP3 via FFmpeg). This distinguishes it well from sibling tools like media_trim_audio and media_extract_audio.

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?

It gives a clear usage context: use this tool to concatenate two or more audio files into a single MP3. However, it does not explicitly name alternative tools or state when not to use it, so the guidance is sufficient but not exhaustive.

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