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

Annotations already declare readOnlyHint=true and openWorldHint=false, covering the safety profile. The description adds useful behavioral context beyond annotations: supported audio formats, that the result is returned as JSON, and the cost of 50 points per call. It does not mention authentication or rate limits, but the added cost and format details are substantive.

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 action and efficiently lists supported formats, return type, and cost. The bilingual repetition adds some redundancy but remains acceptable for a service likely targeting both English and Korean users.

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?

No output schema exists, but the description notes that the converted text is returned as JSON, which fills that gap. Combined with annotations covering the safety profile and the schema covering all parameters, the definition is complete enough for an agent to call the tool correctly, though it lacks routing guidance.

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?

Schema description coverage is 100%, so the input schema already documents all three parameters in detail. The description lists common audio formats, but this overlaps with the schema's allowed MIME types and does not add meaning for the required audio_url, language, or artifact_filter parameters. Baseline 3 is appropriate when the schema does the heavy lifting.

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 states a specific verb and resource: 'Convert a speech audio file to text (STT)'. It clearly distinguishes the tool from siblings like OCR (image-to-text) and TTS (text-to-speech), so an agent can identify its role without opening the schema.

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 explains what the tool does but provides no guidance on when to use it versus alternatives. There is no explicit mention of when-not to use it, what kinds of inputs are appropriate, or how it differs from sibling tools such as youtube_subtitle or video_to_mp3.

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