Fetch a audio downloads[n].url from a completed audio project and return it as inline MCP audio content for compatible clients. Pass the exact full signed URL from downloads[n].url without trimming query parameters; expires_at is separate metadata, not part of the URL.
| Name | Required | Description | Default |
|---|---|---|---|
| max_bytes | No | ||
| download_url | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the behavioral disclosure burden. It reveals that the result is inline MCP audio content rather than a plain URL, and warns that the signed URL must be passed exactly, including query parameters, with expires_at treated as separate metadata. It does not describe max_bytes limits or error behavior, but the critical runtime constraints are surfaced.
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 purposeful sentences: the first states the operation and audience, the second delivers the critical URL-handling instruction. There is no filler, and the most important operational warning is placed directly with the relevant parameter.
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 two-parameter tool with no output schema and no annotations, the description provides enough to call it correctly: the source of the URL, the inline return behavior, and the URL format constraint. It leaves max_bytes semantics and failure behavior implicit, but those are secondary given the schema default and the simplicity of the operation.
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 0%, so the description must compensate. It adds essential semantics for download_url: the value must be the exact full signed URL, query parameters must not be trimmed, and expires_at is not part of the URL. However, max_bytes receives no explanatory coverage beyond what the schema default implies.
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 action ('Fetch... and return it as inline MCP audio content'), a concrete resource ('downloads[n].url' from a completed audio project), and naturally differentiates from sibling fetch_image_download and fetch_video_download through the audio resource. The inline-content detail adds clarity about what the tool actually does beyond simply fetching a URL.
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?
It clearly scopes use to completed audio projects and inline-audio-compatible clients, which gives the agent a clear selection context. It does not explicitly name alternatives or state when not to use it, but the audio-specific target is enough to route correctly alongside its image and video counterparts.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Most tools are differentiated by product-specific prefixes (e.g., lip_sync, text_to_video, image_upscaler), but the set contains many overlapping create_image/create_video tools, and generic editors like ai_image_editor_create_image and ai_video_editor_create_video blur boundaries with their more specific counterparts. Face/body swapping tools also occupy a similar conceptual space, requiring careful description reading to avoid misselection.
Names generally follow a descriptive snake_case pattern of feature plus action (e.g., text_to_video_create_video, image_projects_delete, wait_for_image_project). Minor inconsistencies like ai_face_editor_edit_image versus the dominant create_image suffix, and the mixed ai_ prefix usage across tools, prevent a perfect score.
44 tools is a large surface for an MCP server, even for a broad media-generation API. The count exceeds the 25+ threshold and creates a heavy selection burden, especially with over a dozen create tools for images and videos.
The surface covers the full create-to-download workflow for image, video, and audio: creation, status polling, wait helpers, fetch helpers, delete, and asset upload support. Minor gaps include no list/cancel endpoints and no general project search, but agents can complete core tasks without dead ends.
