fetch_video_downloadFetch a completed project's video as an embedded MCP binary resource 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 readOnlyHint, destructiveHint=false and openWorldHint=false, so the description's added context is what earns credit: the HTTPS/Magic Hour media host requirement and the 8 MiB ceiling with fallback. It does not mention auth requirements beyond the signed URL or failure modes for expired signatures.
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 what the tool returns, then how to call it, then constraints, then the escape hatch. No sentence is redundant with another.
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 fetch tool with no output schema, the description covers return shape (embedded binary resource), host/transport requirement, and size limit. Only the error/expiry behavior is left implicit, which is a small gap.
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 carries the burden and does so for both parameters: download_url must be the exact signed URL including query parameters, and max_bytes caps the payload below the 8 MiB default. Minor gap: no guidance on what happens if max_bytes exceeds the actual file size or on URL expiry.
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 and resource ('Fetch a completed project's video') plus the delivery mechanism ('embedded MCP binary resource for compatible clients'), which distinguishes it from sibling fetchers like fetch_image_download and fetch_audio_download. An agent can tell what it gets back 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?
Gives concrete invocation guidance ('Use the exact signed download URL, including query parameters') and an explicit alternative for the oversized case ('Use the signed URL directly for larger files'), plus a client-compatibility caveat. It stops short of naming sibling tools or stating preconditions such as project completion state.
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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