<!-- Clearly explain the need for these changes: -->
This PR adds a new internal block, **AI Image Editor**, which enables
**text-based image editing** via BlackForest Labs’ Flux Kontext models
on Replicate. This block allows users to input a prompt and optionally a
reference image, and returns a transformed image URL. It supports two
model variants (Pro and Max), with different cost tiers. This
functionality will enhance multimedia capabilities across internal agent
workflows and support richer AI-powered image manipulation.
---
### Changes 🏗️
* Added `FluxKontextBlock` in `backend/blocks/flux_kontext.py`
* Uses `ReplicateClient` to call Flux Kontext Pro or Max models
* Supports inputs for `prompt`, `input_image`, `aspect_ratio`, `seed`,
and `model`
* Outputs transformed image URL or error
* Added credit pricing logic for Flux Kontext models to
`block_cost_config.py`:
* Pro: 10 credits
* Max: 20 credits
* Added documentation for the new block at
`docs/content/platform/blocks/flux_kontext.md`
* Updated block index at `docs/content/platform/blocks/blocks.md` to
include Flux Kontext
---
### Checklist 📋
#### For code changes:
* [x] I have clearly listed my changes in the PR description
* [x] I have made a test plan
* [x] I have tested my changes according to the test plan:
<!-- Put your test plan here: -->
* [x] Prompt-only input generates an image
* [x] Prompt with image applies edit correctly
* [x] Image respects specified aspect ratio
* [x] Invalid image URL returns helpful error
* [x] Using the same seed gives consistent output
* [x] Output chaining works: result URI can be used in downstream blocks
* [x] Output from Max model shows higher fidelity than Pro
<details>
<summary>Example test plan</summary>
* [x] Create from scratch and execute an agent using Flux Kontext with
at least 3 blocks
* [x] Import agent with Flux Kontext from file upload, and confirm
execution
* [x] Upload agent (with Flux Kontext block) to marketplace (internal
test)
* [x] Import agent from marketplace and confirm correct execution
* [x] Edit agent with Flux Kontext block from monitor and confirm output
</details>
#### For configuration changes:
* [x] `.env.example` is updated or already compatible with my changes
* [x] `docker-compose.yml` is updated or already compatible with my
changes
* [x] I have included a list of my configuration changes in the PR
description (under **Changes**)
* No new environment variables or services introduced
<details>
<summary>Examples of configuration changes</summary>
* N/A
</details>
---------
Co-authored-by: Zamil Majdy <zamil.majdy@agpt.co>
