PhotoForge MCP Server

change_background

Replace an existing image's background with a new studio scene described by a prompt, optionally matching subject lighting to the new backdrop.

Instructions

Swap or generate a new studio background for an existing image.

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": {
      "imageUrl": "<imageUrl>",
      "backgroundPrompt": "<backgroundPrompt>"
    },
    "name": "change_background"
  }
}

Input Schema

Name	Required	Description
`imageUrl`	Yes	Source photo URL to modify background.
`lightingMatch`	No	Whether to match subject lighting to background.
`backgroundPrompt`	Yes	Description of the new background scene.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.0Oct 24, 2026

TDQS

C2.9/5.0

Behavior2/5

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

With no annotations, the description carries the full burden. It does not say whether this consumes credits, whether it is synchronous or async, whether the original image is preserved, or what the result contains — all material for an image-generation mutation.

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

Conciseness4/5

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

A single front-loaded sentence with zero filler, appropriately sized for a simple three-parameter tool. The only slight weakness is that 'swap or generate' leaves the two modes undifferentiated.

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?

No annotations and no output schema exist, so the description is the only place to learn behavioral facts, yet it omits return value, cost, and async behavior. Parameter documentation is complete, but the surrounding context an agent needs is missing.

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%, with all three parameters documented including the lightingMatch default. The description adds no additional meaning beyond the schema, so the baseline 3 applies.

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 states a specific verb ('Swap or generate') and resource ('studio background') scoped to 'an existing image', which is clearly distinct from siblings like remove_background or generate_photo. It does not name those siblings or explain the boundary, but the operation itself is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'for an existing image' weakly implies a precondition, but there is no explicit guidance on when to pick this over generate_photo, remove_background, or upscale_photo, nor any exclusion criteria. An agent must infer the routing decision entirely.

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