generate_image_with_alt

Defined in dapp/app/lib/mcp/tools/image-generate-workflow.ts, this tool centralizes OpenAI image creation and the client-side delivery contract.

Pipeline Highlights

• Input schema — accepts a prompt plus an optional name. Sizes/quality are fixed by aiServerConfig.image.defaults to keep runtime predictable.
• Generation — callOpenAIImage is the sole generator path today; it enforces the OpenAI provider and falls back to fetching the signed URL when b64_json is absent.
• Alt Text — generateAltText uses the configured vision provider (openai or lmstudio) so every image ships with accessible copy even though the pixels never touch disk.
• Streaming — the handler pushes JSON first ({ kind: 'store-image', name, width, height, dataBase64 }) and then the <img src="store://..."> text segment so hydrators can populate caches before the transcript renders.

Image Delivery

Images generated by tools are never stored server-side. The workflow (image-generate-workflow.ts) streams a base64 payload through SSE, marks it with kind: 'store-image', and inserts a placeholder <img src="store://image/..."> tag in the text portion. The client’s hydration hook writes the data into memory so parseContentWithMedia.ts can render it inline.

// dapp/app/lib/mcp/tools/image-generate-workflow.ts
const imageGenerateWorkflow: Tool<Params> = {
  name: 'generate_image_with_alt',
  description: 'Generate an image and emit a store:// payload + alt text.',
  async handler({ prompt, name }) {
    const { pngBase64, w, h } = await callOpenAIImage(prompt);
    const alt = await generateAltText(`data:image/png;base64,${pngBase64}`);
    const fileName = uniqueName(name);
    const json = jsonResult({
      kind: 'store-image',
      name: fileName,
      mime: 'image/png',
      width: w,
      height: h,
      alt,
      dataBase64: pngBase64,
    });
    const text = textResult(
      `<img src="store://image/${fileName}" alt="${alt.replace(/"/g, '&quot;')}" width="${w}" height="${h}" />`,
    );
    return { content: [...json.content, ...text.content] };
  },
};

Presenter Behavior

dapp/components/chatBot/ToolActivity/catalog/presenters/generate_image_with_alt.presenter.ts keeps the UI minimal:

Ties to the Frontend