image-gen-mcp

Configurable, provider-agnostic image generation, as a DeepSeek Harness plugin. Point it at any OpenAI-compatible /v1/images/generations endpoint and the model gains image_generate and image_config_status — plus a bundled skill that tells it when to use them.

A Codex plugin that exposes image generation tools through MCP with a configurable base URL and API key.

Install

DeepSeek Harness Desktop — open Plugins in the sidebar, choose Add plugin, and enter:

https://github.com/bauerelizabeth07139/image-gen-mcp

Then switch the new dsh-image-gen-mcp bundle on, and give it a backend (see Configuration — without a base URL and key the plugin deliberately mounts nothing and says so).

dsh CLI — install it into the profile you actually boot:

dsh plugin --profile web add bauerelizabeth07139/image-gen-mcp

No git on the machine? pnpm resolves a git shorthand with git ls-remote, which fails with 'git' is not recognized when git is missing. Use the tarball instead — that path is plain HTTPS:

dsh plugin --profile web add https://codeload.github.com/bauerelizabeth07139/image-gen-mcp/tar.gz/master

The same address works in the Desktop Add plugin dialog. Replace master with a commit SHA to pin an exact revision (/tar.gz/<sha>).

Uninstall with dsh plugin --profile web remove dsh-image-gen-mcp.

Requirements

• Node.js ≥ 22 — the harness itself; the server is plain Node with no npm dependencies, so there is nothing to install.
• A backend: a base URL that answers POST {baseUrl}/v1/images/generations and an API key for it. The base URL must not include /v1.

Tools

Tool	What it does
mcp__image_generation__image_generate	Generates an image from a prompt. Parameters: prompt (required), model, size, n.
mcp__image_generation__image_config_status	Reports whether the base URL and key are configured — ask this first when a generation fails for configuration reasons.

Bundled skill

skills/image-generation/SKILL.md is registered by the plugin, so the model knows the workflow: check image_config_status, generate with image_generate, return the artifact or an actionable error. It is adapted from the repository's original Codex skill — same workflow, harness tool names, plus a note about base64 payloads.

Configuration

Key	Environment variable	Default	Meaning
baseUrl	IMAGE_GEN_BASE_URL	(none — required)	backend base URL, without /v1
apiKey	IMAGE_GEN_API_KEY	(none — required)	credential for that backend
model	IMAGE_GEN_DEFAULT_MODEL	(empty)	default model; the server picks dall-e-3 in openai mode and gpt-image-1 in generic mode when this is empty
provider	IMAGE_GEN_PROVIDER	generic	generic (URL response) or openai (base64 response)
timeoutMs	IMAGE_GEN_TIMEOUT_MS	30000	the server's own HTTP budget
toolCallTimeoutMs	—	120000	DSH's per-call budget
env	—	{}	raw environment passthrough

Example loader row:

- id: dsh-image-gen-mcp
  name: 'dsh-image-gen-mcp'
  config:
    baseUrl: 'https://api.example.com'
    apiKey: 'sk-...'
    model: 'gpt-image-1'
    provider: 'generic'

The credential is forwarded explicitly: the harness scrubs credential-shaped variables (KEY, TOKEN, SECRET, PASSWORD) out of the environment a child would inherit, so an exported IMAGE_GEN_API_KEY is read at load time and written into the child's environment by the plugin.

Why this plugin ships a bridge

The server frames its stdio transport the LSP way — Content-Length: <n> followed by a blank line — while the MCP client inside DeepSeek Harness reads newline-delimited JSON. Mounted directly, the handshake would simply time out. bridge.mjs translates in both directions: NDJSON in from the harness, Content-Length frames to the server, and the reverse on the way back. Message bodies are reframed byte for byte, never re-parsed.

How it is mounted

index.js registers the skill, then mounts scripts/server.mjs through the bridge over stdio with failOnStartupError: true. If baseUrl or apiKey is missing it logs a warning and mounts nothing — a server that exits at startup would otherwise fail the whole bundle load — while still registering the skill, so the model can tell the user exactly what to configure.

Development

npm test

Four suites, all Harness-free: the manifest and card metadata (test/plugin.test.mjs), the bridge's framing and round trip (test/bridge.test.mjs), the stdio mount and credential forwarding (test/mount.test.mjs), and the bundled skill's registration (test/skill.test.mjs). The repository's own Python validators still work: python scripts/validate_plugin.py ., python scripts/test_server.py, python tests/test_provider_modes.py.

Repository layout

Path	Purpose
index.js	the DSH plugin: skill provider + stdio mount
bridge.mjs	NDJSON ↔ Content-Length translation
cordis.patch.yml	the loader row that activates the plugin
skills/image-generation/	the bundled skill, adapted from the original
locale/{en,zh}.json, assets/icon.svg	card title, description and artwork
scripts/server.mjs	the MCP server, unchanged
scripts/server.py, scripts/test_server.py	the original Python HTTP debug server and its test, unchanged
scripts/validate_plugin.py, tests/	the original Codex-plugin validators and tests, unchanged
.mcp.json, .codex-plugin/	the original Codex plugin manifest, unchanged
README.opencode.md	the repository's original README, verbatim

Other hosts (unchanged)

{
  "mcpServers": {
    "image-generation": {
      "command": "node",
      "args": ["scripts/server.mjs"],
      "env": {
        "IMAGE_GEN_BASE_URL": "${IMAGE_GEN_BASE_URL}",
        "IMAGE_GEN_API_KEY": "${IMAGE_GEN_API_KEY}"
      }
    }
  }
}

Two caveats carried over from the original setup: the relative scripts/server.mjs needs the repository root as the working directory, and a host that frames with newline-delimited JSON (like DSH) needs the bridge: node bridge.mjs -- node scripts/server.mjs.

License

MIT — the repository's own licence file, unchanged.