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by io.github.magichourhq
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fetch_video_download

Fetch a video downloads[n].url from a completed video project and return it as an embedded MCP binary resource 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.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
contextNoExplain 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."
max_bytesNo
download_urlYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changed
    • addedInput schema / properties / context
      Added 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"
+}
  2. First observed

TDQS

A3.8/5.0
Behavior3/5

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

With no annotations, the description carries the full burden and does disclose meaningful traits: the result is an embedded MCP binary resource, it is limited to compatible clients, and the URL is signed and time-limited. It omits auth requirements, behavior on expired URLs, and error handling, leaving notable gaps for a fetch tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with purpose and followed by the crucial URL-passing caveat; every clause earns its place. The phrase 'for compatible clients' is slightly vague but does not waste much space.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema or annotations, and three parameters exist, so the description should do heavy lifting. It covers purpose, return type, and URL format well but leaves max_bytes behavior and failure modes undocumented, making it adequate rather than complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 33% (just the context field), so the description must compensate, and it does for the critical parameter: it explains that download_url must be the exact full signed URL without trimming query parameters and that expires_at is separate metadata. It adds nothing for max_bytes, but the key parameter is well covered.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb (Fetch) and resource (a video download from a completed video project) and describes the return as an embedded binary resource, clearly distinguishing it from siblings like fetch_image_download, fetch_audio_download, and video_assets_generate_presigned_url.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It implies usage by scoping to 'a completed video project' and noting it is 'for compatible clients', which gives context. However, it never states when to prefer this over video_assets_generate_presigned_url or what to do for incompatible clients, so the routing guidance is only implied.

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

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