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

The description adds that the output includes timed segments and is returned as JSON, which is useful beyond the bare 'transcribe' statement. Annotations already indicate non-read-only behavior, and the description does not contradict this. However, it does not disclose potential side effects like credit consumption or whether the operation is synchronous—both relevant given the fattly suite includes a credits tool and many async generation tools.

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?

Two concise sentences, front-loaded with the core action, and no filler. The first sentence captures the main purpose and output; the second clarifies the return format. Every word contributes.

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 tool has three parameters, all documented in the schema, but no output schema. The description mentions 'Returns the transcript as JSON' but does not outline the exact JSON structure, which could be ambiguous. It also relies on the schema to convey that audioUrl must come from fattly_upload_image, which is acceptable since that is in the schema. Given these factors, the description is adequate but not fully complete.

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% with detailed descriptions for all three parameters (audioUrl, task, language). The description itself adds no parameter-specific information, so it provides no extra meaning beyond what the schema already documents. Baseline of 3 is appropriate.

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 ('Transcribes') and resource ('audio file') with output details ('text with timed segments') and format ('JSON'). This clearly differentiates it from sibling tools like fattly_generate_audio, which generates audio, and fattly_video_status, which tracks video status.

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 implies usage for transcription but does not explicitly mention alternatives or when not to use it. There is no guidance on selection among siblings, such as preferring this over other audio-related tools. The purpose is clear enough that an agent could infer, but explicit exclusions are absent.

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