audio_merge

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

With no annotations, the description must carry the transparency burden. It does disclose a key behavior—matching files are joined without re-encoding, instantly and losslessly—and lists accepted formats and size limits. However, it omits what happens when files do not match (presumably re-encoding) and does not mention whether original files are modified or how output is named. These gaps prevent a higher score.

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 remarkably concise: three sentences that front-load the core purpose, then add key behavioral details and constraints. Every sentence earns its place—there is no fluff, repetition, or unnecessary jargon. This is an exemplary structure for a tool description.

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 merge tool with four parameters and no output schema, the description covers the essential aspects: what it does, when it is lossless, and what inputs are acceptable. It does not explain the re-encoding fallback behavior or output naming, but the schema covers parameter defaults and non-overwrite behavior. Overall, it is sufficiently complete for an agent to select and invoke the 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?

The input schema already describes all parameters (100% coverage), so the baseline is 3. The description adds meaningful context: it clarifies that the order in 'paths' matters ('in the order you picked') and specifies accepted file types and size limits, which inform valid values for 'paths' and 'format.' This extra semantic value justifies a 4.

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 audio' and then specifies the result: 'Join several recordings into one, in the order you picked.' This clearly states the verb, resource, and outcome, making it distinct from sibling tools like audio_convert or audio_trim. The purpose is immediately understandable and not a tautology.

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 clearly indicates the intended use case: joining multiple recordings in a chosen order. It also provides constraints (accepted formats, size limit) that help decide if the tool is appropriate. However, it does not explicitly mention alternatives or include a 'when not to use' statement, so it stops short of a full 5.

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