fetch_audio_downloadFetch a completed project's audio as inline MCP audio content for compatible clients. Use the exact signed download URL, including query parameters. Requires HTTPS at the configured Magic Hour media host. Read-only; limited to 8 MiB, or a smaller requested max_bytes. Use the signed URL directly for larger files.
| Name | Required | Description | Default |
|---|---|---|---|
| max_bytes | No | ||
| download_url | Yes |
Changes observed during successful MCP inspections.
Input schema / properties / max_bytes / defaultPrevious value: -15728640New value: +8388608Input schema / properties / contextRemoved value: -{
- "description": "Explain in 15-25 words, in third person, why this tool is called and how it supports the user's goal. For analytics only. You MUST describe only the abstract purpose of the tool call. NEVER include, repeat, paraphrase, or infer personal, sensitive, or identifying information from the user request or tool results, including names, emails, phone numbers, IPs, IDs, or credentials. You MUST generalize specific entities into roles such as \"a user\", \"the customer\", or \"an account\". Example: \"Retrieving a customer's recent orders to investigate a billing issue and help support determine the appropriate resolution.\"",
- "type": "string"
-}Input schema / properties / contextAdded value: +{
+ "description": "Explain in 15-25 words, in third person, why this tool is called and how it supports the user's goal. For analytics only. You MUST describe only the abstract purpose of the tool call. NEVER include, repeat, paraphrase, or infer personal, sensitive, or identifying information from the user request or tool results, including names, emails, phone numbers, IPs, IDs, or credentials. You MUST generalize specific entities into roles such as \"a user\", \"the customer\", or \"an account\". Example: \"Retrieving a customer's recent orders to investigate a billing issue and help support determine the appropriate resolution.\"",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only/non-destructive; the description adds real context: the 8 MiB ceiling, the smaller max_bytes option, and the HTTPS-at-media-host prerequisite. It does not describe failure behavior when the host or URL is wrong, so it is not a 5.
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?
Four short sentences, front-loaded with the capability, then the URL requirement, then the size limit and fallback. Nothing is repeated from the title.
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?
With no output schema, the description does say the return is inline MCP audio content, and it covers the size limit, URL form, and transport requirement. A mention of what happens when the project isn't finished would make it 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 coverage is 0%, so the description must carry both parameters, and it does: download_url must be the exact signed URL including query parameters, and max_bytes is framed as a size cap against the 8 MiB default. Neither param is left to guesswork.
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?
States a specific verb+resource: fetch a completed project's audio as inline MCP audio content. That distinguishes it cleanly from the image/video download siblings by the resource type, though it never names those siblings explicitly.
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?
Gives usable conditions: works for compatible clients, needs HTTPS on the configured media host, and explicitly says to use the signed URL directly for files larger than the cap. It stops short of stating when not to use it versus fetch_image_download/fetch_video_download, but those are obvious.
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.