Firefly MCP Server

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Fill image

generative_fill

Fill selected areas of an image using Firefly AI by supplying a source image and mask, generating Adobe output URLs; set wait=false for async jobs.

Instructions

Fill image. Consumes Firefly Services credits. Returns Adobe output URLs. Set wait=false to return an async job.

Input Schema

Name	Required	Description
`n`	No	Compatibility alias for numVariations. Do not supply both.
`mask`	No	Required. Selected areas of a background image that Firefly uses to fill the source image.
`size`	No	The desired width and height for the final expanded image in pixels. The supported sizes for the output images are: Square (1:1) - width 2048px, height 2048px Square (1:1) - width 1024px, height 1024px Landscape (4:3) - width 2304px, height 1792px Portrait (3:4) - width 1792px, height 2304px Widescreen (16:9) - width 2688px, height 1536px (7:4) - width 1344px, height 768px (9:7) - width 1152px, height 896px (7:9) - width 896px, height 1152px .
`wait`	No	Wait for completion, default true. Set false to return the job immediately.
`image`	No	The image to expand. Use a URL or an uploadID as the source for the image. Firefly only allows these listed domains for input URLs in the request: amazonaws.com windows.net dropboxusercontent.com storage.googleapis.com .
`seeds`	No	Array of seed image IDs. These reference images help ensure consistent image generation across multiple API calls. For example, you can use the same seed to generate a similar image with different styles. If specified along with numVariations, the number of seeds must equal numVariations.
`width`	No	Compatibility alias: provide together with height instead of size.
`height`	No	Compatibility alias: provide together with width instead of size.
`prompt`	No	An optional text prompt up to 1024 characters. The longer the prompt the better Firefly performs.
`confirm`	No	Set true only when the user asked for exactly this action.
`maskUrl`	No	Compatibility URL alias for mask.source.url.
`download`	No	Download completed media to FIREFLY_OUTPUT_DIR, default false. Requires wait=true.
`imageUrl`	No	Compatibility URL alias for image.source.url.
`numVariations`	No	Generate this number of variations. numVariations defaults to the number of seed images, or to 1 if you do not specify seeds.
`negativePrompt`	No	An optional text prompt up to 1024 characters. Avoid these characteristics in the generated image. Not supported for Firefly Custom Models on Image Model 3 or Firefly Custom Models on Image Model 4.
`promptBiasingLocaleCode`	No	A hyphen-separated string combining the ISO 639-1 language code and the ISO 3166-1 region, such as en-US. When a locale is set, the prompt will be biased to generate more relevant content for that region. The locale will be auto-detected if not specified based on your profile and the accepted language header.

Schema Changelog

Changes observed during successful MCP inspections.

Changed23 schema fields changedv3.0.0Oct 6, 2026
- addedInput schema / $defs
```
Added value: +{
+  "url": {
+    "description": "The pre-signed URL of an uploaded file. Use a URL or an `uploadID` as the source for the image. Firefly only allows these listed domains in the request: amazonaws.com windows.net dropboxusercontent.com storage.googleapis.com .",
+    "format": "uri",
+    "maxLength": 2083,
+    "minLength": 1,
+    "type": "string"
+  }
+}
```
- changedInput schema / properties / confirm / description
```
Previous value: -"Must be true to spend Firefly Services credits for the operation the user requested."New value: +"Set true only when the user asked for exactly this action."
```
- changedInput schema / properties / image / properties / mask / properties / uploadId / format
```
Previous value: -"uuid4"New value: +"uuid"
```
- addedInput schema / properties / image / properties / mask / properties / url / $ref
```
Added value: +"#/$defs/url"
```
- removedInput schema / properties / image / properties / mask / properties / url / description
```
Removed value: -"The pre-signed URL of an uploaded file. Use a URL or an `uploadID` as the source for the image. Firefly only allows these listed domains in the request: amazonaws.com windows.net dropboxusercontent.com storage.googleapis.com ."
```
- removedInput schema / properties / image / properties / mask / properties / url / format
```
Removed value: -"uri"
```
- removedInput schema / properties / image / properties / mask / properties / url / maxLength
```
Removed value: -2083
```
- removedInput schema / properties / image / properties / mask / properties / url / minLength
```
Removed value: -1
```
- removedInput schema / properties / image / properties / mask / properties / url / type
```
Removed value: -"string"
```
- changedInput schema / properties / image / properties / source / properties / uploadId / format
```
Previous value: -"uuid4"New value: +"uuid"
```
- addedInput schema / properties / image / properties / source / properties / url / $ref
```
Added value: +"#/$defs/url"
```
- removedInput schema / properties / image / properties / source / properties / url / description
```
Removed value: -"The pre-signed URL of an uploaded file. Use a URL or an `uploadID` as the source for the image. Firefly only allows these listed domains in the request: amazonaws.com windows.net dropboxusercontent.com storage.googleapis.com ."
```
- removedInput schema / properties / image / properties / source / properties / url / format
```
Removed value: -"uri"
```
- removedInput schema / properties / image / properties / source / properties / url / maxLength
```
Removed value: -2083
```
- removedInput schema / properties / image / properties / source / properties / url / minLength
```
Removed value: -1
```
- removedInput schema / properties / image / properties / source / properties / url / type
```
Removed value: -"string"
```
- changedInput schema / properties / mask / properties / source / properties / uploadId / format
```
Previous value: -"uuid4"New value: +"uuid"
```
- addedInput schema / properties / mask / properties / source / properties / url / $ref
```
Added value: +"#/$defs/url"
```
- removedInput schema / properties / mask / properties / source / properties / url / description
```
Removed value: -"The pre-signed URL of an uploaded file. Use a URL or an `uploadID` as the source for the image. Firefly only allows these listed domains in the request: amazonaws.com windows.net dropboxusercontent.com storage.googleapis.com ."
```
- removedInput schema / properties / mask / properties / source / properties / url / format
```
Removed value: -"uri"
```
- removedInput schema / properties / mask / properties / source / properties / url / maxLength
```
Removed value: -2083
```
- removedInput schema / properties / mask / properties / source / properties / url / minLength
```
Removed value: -1
```
- removedInput schema / properties / mask / properties / source / properties / url / type
```
Removed value: -"string"
```
First observedv2.0.0Oct 2, 2026

TDQS

C2.6/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=true, so safety is covered structurally. The description adds genuinely useful context beyond that: it consumes Firefly Services credits (cost) and returns Adobe output URLs. It still omits failure/retry behavior and what the async job returns, so it lands at a solid but not rich 3.

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?

Four short sentences with no filler and the core action front-loaded. It is efficient, though the terseness verges on under-specification for a tool of this complexity rather than trimming redundant content.

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?

With 16 parameters, zero required fields, nested objects, and no output schema, the description is too thin: it never states that a mask and source image are effectively needed, nor how fill differs from expand or composite. The credit and URL notes are helpful but do not cover what an agent needs to call this correctly.

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% and the schema already documents wait, mask vs image, aliases, and sizing in detail, so baseline is 3. The description's only parameter note (wait=false) merely repeats the schema and clarifies nothing about the mask requirement or the 16-parameter/alias surface.

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

Purpose2/5

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

"Fill image" essentially restates the title with no verb+resource specificity and gives no differentiation from close siblings like generative_expand, generate_similar, or generate_object_composite. The remaining sentences describe side effects (credit consumption, output format) rather than what filling actually does.

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 only usage instruction is "Set wait=false to return an async job," which is a parameter note, not guidance on when to pick this tool over generative_expand or the composite tools. No when-not, no prerequisites, no workflow context for the mask/image pairing an agent must reason about.

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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Fill image

Instructions

Input Schema

Schema Changelog

TDQS

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