Veo 3.1 MCP Server

extend_video

Extend Veo-generated videos by adding seconds to continue the sequence. Specify duration and optional continuation prompt to maintain visual consistency.

Instructions

Extend a Veo-generated video by additional seconds. Input video must be from a previous Veo generation (not an arbitrary video).

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": {
      "videoFileUri": "<videoFileUri>",
      "additionalSeconds": "<additionalSeconds>"
    },
    "name": "extend_video"
  }
}

Input Schema

Name	Required	Description
`videoFileUri`	Yes	FileUri of the Veo-generated video to extend
`additionalSeconds`	Yes	Number of seconds to add (typically 7 for 8s extension)
`prompt`	No	Optional: Continuation prompt describing what should happen next
`model`	No	Model to use (default: fast)
`seed`	No	Optional seed for reproducibility

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jan 25, 2026

TDQS

B3.3/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden. It mentions the input constraint (Veo-generated video only) but lacks details on permissions, rate limits, whether the extension is reversible, or what the output looks like (e.g., file format, processing time). For a mutation tool with zero annotation coverage, this is a significant gap in behavioral disclosure.

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 sentences with zero waste, front-loaded with the core purpose and followed by a key constraint. Every sentence earns its place by adding essential information without redundancy or fluff.

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?

Given the tool has 5 parameters, no annotations, and no output schema, the description is adequate but incomplete. It covers the purpose and input constraint but lacks behavioral details (e.g., mutation effects, error handling) and output information, which are important for a video extension tool with multiple parameters.

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 description coverage is 100%, so the schema already documents all parameters thoroughly. The description adds minimal value beyond the schema by hinting at the input constraint ('from a previous Veo generation'), but doesn't provide additional syntax, format details, or usage examples for parameters. Baseline 3 is appropriate when the schema does the heavy lifting.

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?

The description clearly states the action ('extend') and resource ('Veo-generated video'), specifying it adds seconds to a video. It distinguishes from arbitrary video processing by noting the input must be from previous Veo generation, but doesn't explicitly differentiate from sibling tools like 'start_video_generation' or 'get_video_job'.

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 stating the input video must be from a previous Veo generation, which provides some context. However, it doesn't specify when to use this tool versus alternatives like 'start_video_generation' for new videos or 'get_video_job' for checking status, nor does it mention prerequisites or exclusions beyond the input requirement.

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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