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

With no annotations, the description carries the burden of disclosure. It reveals that the tool 'processes in the browser' and costs more credits than other workspaces, plus details about welcome credits and Day Pass exclusion. However, it does not disclose core operational behavior such as output format (e.g., SRT/VTT), how the video input is provided, or what happens if no subtitles exist. The pricing/credit context is useful but leaves key behavioral aspects unexplained.

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 front-loads the core function in the first sentence but then spends five sentences on credit/workspace pricing details. This is verbose and largely redundant with the mioffice_pricing_info tool. The pricing content could be condensed or moved, making the description more focused. Only the first sentence earns its place for tool selection.

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 simple tool with no parameters and no output schema, the description still misses essential operational details: how the video file is supplied (since there are no params, the mechanism is unclear), the return format of extracted subtitles, and behavior when no subtitles are embedded. The pricing context is well covered, but the actual tool workflow is under-specified.

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 (empty input schema), so the baseline for parameter semantics is 4. The description adds no parameter information, but there is nothing to document. The schema coverage is trivially 100% because there are no properties, so the description does not need to compensate.

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 states the tool's function: 'Extract embedded subtitles from MKV/MP4 video.' This is a specific verb ('Extract') and resource ('subtitles from video'), making it distinct from siblings like mio_ai_video_subtitler (which adds subtitles) or mio_ai_transcriber (which transcribes speech). The purpose 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 description provides no guidance on when to use this tool over alternatives, such as explaining that it only works with embedded subtitle streams and is not for generating or translating subtitles. Instead, it focuses on credit and workspace pricing, which is not usage guidance. No exclusions or alternative tool references are given.

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