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

With no annotations, the description carries the transparency burden. It does disclose that it processes in the browser and uses credits, which is useful. However, it doesn't explain the output behavior (e.g., where the MP4 is saved, whether the original is modified) or the input method (no parameters). This is a partial disclosure, not a full one.

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 front-loaded with the core purpose but then spends four sentences on pricing and credit details. While relevant, this is more verbose than necessary and could be condensed. It is structured clearly but contains non-essential operational cost information that might be better placed in a central pricing reference.

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 description covers the core functionality and credit implications, but misses the execution model: how does an agent actually initiate the conversion with no parameters? It doesn't state whether the tool requires a prior uploaded file, a workspace context, or returns a download link. Given the simple purpose, it's near adequate but has a notable gap in actionable usage context.

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 tool has zero parameters, so the schema provides nothing. The description adds no parameter information, but the baseline for 0 params is 4. The description does not need to explain syntax or formats, though it could have clarified that the tool operates on a current session/file rather than taking direct arguments.

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 explicitly states 'Convert MKV videos to MP4 format' with a specific verb and resource, clearly distinguishing it from sibling tools like AVI to MP4 or MOV to MP4. The format pair is unambiguous.

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 purpose makes clear when to use this tool (when the user has an MKV file and wants MP4). No explicit exclusions or alternative recommendations are given, but the format-specific naming and description provide sufficient context for selection.

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