MoviePy MCP Server

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fade

Apply fade-in and fade-out to video or audio clips by specifying durations. Handles transitions to black for video and silence for audio.

Instructions

Add fade-in and/or fade-out. Works for video (to black) and audio.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "clip_id": "<clip_id>"
    },
    "name": "fade"
  }
}

Input Schema

Name	Required	Description	Default
`clip_id`	Yes
`fade_in_seconds`	No
`fade_out_seconds`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 1, 2026

TDQS

B3.3/5.0

Behavior2/5

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

With no annotations, the description must disclose behavioral traits. It mentions fade-to-black for video but does not state whether the clip is modified in place, whether a new clip is returned, or any side effects or prerequisites. The behavioral burden is unmet.

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

Conciseness5/5

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

The description is two concise sentences, front-loaded with the action and key scope. Every word adds value with no redundancy.

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

Completeness2/5

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

For a 3-parameter tool with no annotations and an output schema, the description is incomplete. It does not clarify whether it applies to images (likely not), how the tool behaves with existing fades, or what the output represents. It leaves significant gaps for safe invocation.

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

Parameters2/5

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 does not name or explain the parameters beyond the effect name; the param names ('fade_in_seconds', 'fade_out_seconds') are self-explanatory, but the description adds no additional meaning about units, defaults, or behavior with zero values.

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 clearly states the action ('Add') and the resource ('fade-in and/or fade-out'), and it distinguishes the tool from siblings by noting it applies to video (to black) and audio. This is specific and unambiguous.

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?

The description implies the tool is for adding fades to video or audio clips, giving some context. However, it does not explicitly state when to use this tool versus alternatives (e.g., set_volume for audio) or when not to use it, so guidance is implied rather than explicit.

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