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capcut_render_preview_proxy

Render a lightweight 540x960 proxy preview MP4 from a CapCut draft spec via FFmpeg to view edits without launching CapCut.

Instructions

Render a fast, lightweight 540x960 proxy preview MP4 directly from the draft spec using FFmpeg (~2-4 seconds), allowing agents/users to view the edit without launching CapCut.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
widthNo
heightNo
draft_nameYes
output_mp4_pathYes

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A3.6/5.0
Behavior3/5

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

No annotations are provided, so the description carries the full behavioral burden. It discloses key traits: the output format (MP4), approximate execution time (~2-4 seconds), use of FFmpeg, and the independence from CapCut. However, it omits whether the tool requires the draft to exist, whether it overwrites existing files at output_mp4_path, or any permission/error conditions.

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?

Single, front-loaded sentence that conveys purpose, method, speed, and key benefit without any waste. Every phrase earns its place.

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?

An output schema exists, so return values need not be explained. However, with no annotations and 0% parameter coverage, critical operational details (e.g., required draft_name, output path behavior, resolution limits beyond defaults) are missing. The description is complete enough for basic understanding but lacks the specificity needed for correct 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 all four parameters (draft_name, output_mp4_path, width, height) lack documentation in both schema and description. The description mentions 'draft spec' and '540x960', which loosely ties to draft_name and defaults for width/height, but does not clarify the required parameters or the output path semantics. The description fails to compensate for the coverage gap.

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?

States a specific verb (Render) and resource (proxy preview MP4) with distinguishing details: 540x960 resolution, sourced from the draft spec, and 'without launching CapCut.' This clearly separates it from siblings like capcut_assemble_ugc_video or capcut_inspect_draft.

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 usage by explaining the benefit ('view the edit without launching CapCut') and the speed advantage, but does not explicitly state when to use this versus alternatives like full renders or inspect_draft. Usage is inferable rather than guided.

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