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ae_render_preview

Render an After Effects composition or time range to H.264 MP4 or PNG for review; queued items pause and long renders return a command ID.

Instructions

Render a composition (or a time range) through the Render Queue to an H.264 MP4 or a PNG sequence for the user to watch. Other queued items are paused during the render and restored. Blocks After Effects while rendering; long renders return a commandId for ae_get_result.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "ae_render_preview"
  }
}

Input Schema

Name	Required	Description
`comp`	No	Composition name or numeric item id. Omit to use the active composition.
`half`	No	Render at half resolution (faster).
`path`	No	Output file (mp4) or folder (png). Default: <bridge>/renders.
`start`	No
`format`	No	Default mp4.
`duration`	No
`timeoutMs`	No	Default 600000.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Oct 17, 2026

TDQS

A3.8/5.0

Behavior4/5

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

With no annotations, the description carries the full burden and does well: it discloses that other queued items are paused and restored, that it blocks After Effects, and that long renders return a commandId for ae_get_result. It does not state whether existing output files are overwritten or any auth/permission requirements, keeping it at a 4.

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?

Three tight sentences with zero waste, front-loaded with the purpose and followed by side effects and async behavior. Every sentence earns its place.

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

Completeness4/5

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

Given no annotations and no output schema, the description covers purpose, output formats, queue side effects, blocking behavior, and the async follow-up path. It leaves the start/duration semantics and file-overwrite behavior unexplained, so it is strong but not fully complete.

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

Parameters3/5

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

Schema coverage is 71%, so most params (comp, half, path, format, timeoutMs) are already documented by the schema. The description hints at the time range ('or a time range') but sheds no light on the undocumented 'start' and 'duration' params, so it adds little beyond the schema.

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

Purpose4/5

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

Clear specific verb+resource: 'Render a composition (or a time range) through the Render Queue to an H.264 MP4 or a PNG sequence.' This distinguishes it well from the still-capture siblings (ae_capture_frame/ae_capture_frames), but it never explicitly contrasts with them, so it stops short of a 5.

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?

Usage is implied by 'for the user to watch' (i.e., when you need a viewable preview) and the guidance to poll ae_get_result for long renders. However, there is no explicit when-to-use versus ae_capture_frame, no prerequisites, and no when-not guidance.

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