feat: migrate fal workflow to server (#7581)

2026-02-13 12:55:00 +00:00 · 2024-07-26 04:04:38 +00:00
parent cb0d91facd
commit 470262d400
24 changed files with 741 additions and 299 deletions
--- a/packages/backend/server/src/plugins/copilot/controller.ts
+++ b/packages/backend/server/src/plugins/copilot/controller.ts
@@ -288,6 +288,7 @@ export class CopilotController {
      if (latestMessage) {
        params = Object.assign({}, params, latestMessage.params, {
          content: latestMessage.content,
+          attachments: latestMessage.attachments,
        });
      }

@@ -302,14 +303,22 @@ export class CopilotController {
          merge(
            // actual chat event stream
            shared$.pipe(
-              map(data =>
-                data.status === GraphExecutorState.EmitContent
-                  ? {
+              map(data => {
+                switch (data.status) {
+                  case GraphExecutorState.EmitContent:
+                    return {
                      type: 'message' as const,
                      id: messageId,
                      data: data.content,
-                    }
-                  : {
+                    };
+                  case GraphExecutorState.EmitAttachment:
+                    return {
+                      type: 'attachment' as const,
+                      id: messageId,
+                      data: data.attachment,
+                    };
+                  default:
+                    return {
                      type: 'event' as const,
                      id: messageId,
                      data: {
@@ -317,8 +326,9 @@ export class CopilotController {
                        id: data.node.id,
                        type: data.node.config.nodeType,
                      } as any,
-                    }
-              )
+                    };
+                }
+              })
            ),
            // save the generated text to the session
            shared$.pipe(
@@ -378,6 +388,7 @@ export class CopilotController {

      const source$ = from(
        provider.generateImagesStream(session.finish(params), session.model, {
+          ...session.config.promptConfig,
          seed: this.parseNumber(params.seed),
          signal: this.getSignal(req),
          user: user.id,
--- a/packages/backend/server/src/plugins/copilot/prompt.ts
+++ b/packages/backend/server/src/plugins/copilot/prompt.ts
@@ -27,8 +27,6 @@ function extractMustacheParams(template: string) {
  return Array.from(new Set(params));
 }

-const EXCLUDE_MISSING_WARN_PARAMS = ['lora'];
-
 export class ChatPrompt {
  private readonly logger = new Logger(ChatPrompt.name);
  public readonly encoder: Tokenizer | null;
@@ -104,12 +102,12 @@ export class ChatPrompt {
        typeof income !== 'string' ||
        (Array.isArray(options) && !options.includes(income))
      ) {
-        if (sessionId && !EXCLUDE_MISSING_WARN_PARAMS.includes(key)) {
+        if (sessionId) {
          const prefix = income
            ? `Invalid param value: ${key}=${income}`
            : `Missing param value: ${key}`;
          this.logger.warn(
-            `${prefix} in session ${sessionId}, use default options: ${options[0]}`
+            `${prefix} in session ${sessionId}, use default options: ${Array.isArray(options) ? options[0] : options}`
          );
        }
        if (Array.isArray(options)) {
@@ -129,11 +127,28 @@ export class ChatPrompt {
   */
  finish(params: PromptParams, sessionId?: string): PromptMessage[] {
    this.checkParams(params, sessionId);
-    return this.messages.map(({ content, params: _, ...rest }) => ({
-      ...rest,
-      params,
-      content: Mustache.render(content, params),
-    }));
+
+    const { attachments: attach, ...restParams } = params;
+    const paramsAttach = Array.isArray(attach) ? attach : [];
+
+    return this.messages.map(
+      ({ attachments: attach, content, params: _, ...rest }) => {
+        const result: PromptMessage = {
+          ...rest,
+          params,
+          content: Mustache.render(content, restParams),
+        };
+
+        const attachments = [
+          ...(Array.isArray(attach) ? attach : []),
+          ...paramsAttach,
+        ];
+        if (attachments.length && rest.role === 'user') {
+          result.attachments = attachments;
+        }
+        return result;
+      }
+    );
  }
 }

--- a/packages/backend/server/src/plugins/copilot/providers/fal.ts
+++ b/packages/backend/server/src/plugins/copilot/providers/fal.ts
@@ -59,9 +59,15 @@ const FalStreamOutputSchema = z.object({
 });

 type FalPrompt = {
+  model_name?: string;
  image_url?: string;
  prompt?: string;
-  lora?: string[];
+  loras?: { path: string; scale?: number }[];
+  controlnets?: {
+    image_url: string;
+    start_percentage?: number;
+    end_percentage?: number;
+  }[];
 };

 export class FalProvider
@@ -83,10 +89,8 @@ export class FalProvider
    'face-to-sticker',
    'imageutils/rembg',
    'fast-sdxl/image-to-image',
-    'workflows/darkskygit/animie',
-    'workflows/darkskygit/clay',
-    'workflows/darkskygit/pixel-art',
-    'workflows/darkskygit/sketch',
+    'workflowutils/teed',
+    'lora/image-to-image',
    // image to text
    'llava-next',
  ];
@@ -112,7 +116,15 @@ export class FalProvider
    return this.availableModels.includes(model);
  }

-  private extractPrompt(message?: PromptMessage): FalPrompt {
+  private extractArray<T>(value: T | T[] | undefined): T[] {
+    if (Array.isArray(value)) return value;
+    return value ? [value] : [];
+  }
+
+  private extractPrompt(
+    message?: PromptMessage,
+    options: CopilotImageOptions = {}
+  ): FalPrompt {
    if (!message) throw new CopilotPromptInvalid('Prompt is empty');
    const { content, attachments, params } = message;
    // prompt attachments require at least one
@@ -122,17 +134,23 @@ export class FalProvider
    if (Array.isArray(attachments) && attachments.length > 1) {
      throw new CopilotPromptInvalid('Only one attachment is allowed');
    }
-    const lora = (
-      params?.lora
-        ? Array.isArray(params.lora)
-          ? params.lora
-          : [params.lora]
-        : []
-    ).filter(v => typeof v === 'string' && v.length);
+    const lora = [
+      ...this.extractArray(params?.lora),
+      ...this.extractArray(options.loras),
+    ].filter(
+      (v): v is { path: string; scale?: number } =>
+        !!v && typeof v === 'object' && typeof v.path === 'string'
+    );
+    const controlnets = this.extractArray(params?.controlnets).filter(
+      (v): v is { image_url: string } =>
+        !!v && typeof v === 'object' && typeof v.image_url === 'string'
+    );
    return {
+      model_name: options.modelName || undefined,
      image_url: attachments?.[0],
      prompt: content.trim(),
-      lora: lora.length ? lora : undefined,
+      loras: lora.length ? lora : undefined,
+      controlnets: controlnets.length ? controlnets : undefined,
    };
  }

@@ -246,7 +264,7 @@ export class FalProvider
    options: CopilotImageOptions = {}
  ) {
    // by default, image prompt assumes there is only one message
-    const prompt = this.extractPrompt(messages.pop());
+    const prompt = this.extractPrompt(messages.pop(), options);
    if (model.startsWith('workflows/')) {
      const stream = await falStream(model, { input: prompt });
      return this.parseSchema(FalStreamOutputSchema, await stream.done())
--- a/packages/backend/server/src/plugins/copilot/providers/openai.ts
+++ b/packages/backend/server/src/plugins/copilot/providers/openai.ts
@@ -42,6 +42,7 @@ export class OpenAIProvider
  readonly availableModels = [
    // text to text
    'gpt-4o',
+    'gpt-4o-mini',
    'gpt-4-vision-preview',
    'gpt-4-turbo-preview',
    'gpt-3.5-turbo',
--- a/packages/backend/server/src/plugins/copilot/types.ts
+++ b/packages/backend/server/src/plugins/copilot/types.ts
@@ -50,7 +50,7 @@ const PureMessageSchema = z.object({
  content: z.string(),
  attachments: z.array(z.string()).optional().nullable(),
  params: z
-    .record(z.union([z.string(), z.array(z.string())]))
+    .record(z.union([z.string(), z.array(z.string()), z.record(z.any())]))
    .optional()
    .nullable(),
 });
@@ -64,12 +64,21 @@ export type PromptMessage = z.infer<typeof PromptMessageSchema>;
 export type PromptParams = NonNullable<PromptMessage['params']>;

 export const PromptConfigStrictSchema = z.object({
+  // openai
  jsonMode: z.boolean().nullable().optional(),
  frequencyPenalty: z.number().nullable().optional(),
  presencePenalty: z.number().nullable().optional(),
  temperature: z.number().nullable().optional(),
  topP: z.number().nullable().optional(),
  maxTokens: z.number().nullable().optional(),
+  // fal
+  modelName: z.string().nullable().optional(),
+  loras: z
+    .array(
+      z.object({ path: z.string(), scale: z.number().nullable().optional() })
+    )
+    .nullable()
+    .optional(),
 });

 export const PromptConfigSchema =
@@ -175,9 +184,13 @@ export type CopilotEmbeddingOptions = z.infer<
  typeof CopilotEmbeddingOptionsSchema
 >;

-const CopilotImageOptionsSchema = CopilotProviderOptionsSchema.extend({
-  seed: z.number().optional(),
-}).optional();
+const CopilotImageOptionsSchema = CopilotProviderOptionsSchema.merge(
+  PromptConfigStrictSchema
+)
+  .extend({
+    seed: z.number().optional(),
+  })
+  .optional();

 export type CopilotImageOptions = z.infer<typeof CopilotImageOptionsSchema>;

--- a/packages/backend/server/src/plugins/copilot/workflow/executor/chat-image.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/executor/chat-image.ts
@@ -63,28 +63,31 @@ export class CopilotChatImageExecutor extends AutoRegisteredWorkflowExecutor {
    params: Record<string, string>,
    options?: CopilotChatOptions
  ): AsyncIterable<NodeExecuteResult> {
-    const [{ paramKey, id }, prompt, provider] = await this.initExecutor(data);
+    const [{ paramKey, paramToucher, id }, prompt, provider] =
+      await this.initExecutor(data);

    const finalMessage = prompt.finish(params);
+    const config = { ...prompt.config, ...options };
    if (paramKey) {
      // update params with custom key
+      const result = {
+        [paramKey]: await provider.generateImages(
+          finalMessage,
+          prompt.model,
+          config
+        ),
+      };
      yield {
        type: NodeExecuteState.Params,
-        params: {
-          [paramKey]: await provider.generateImages(
-            finalMessage,
-            prompt.model,
-            options
-          ),
-        },
+        params: paramToucher?.(result) ?? result,
      };
    } else {
-      for await (const content of provider.generateImagesStream(
+      for await (const attachment of provider.generateImagesStream(
        finalMessage,
        prompt.model,
-        options
+        config
      )) {
-        yield { type: NodeExecuteState.Content, nodeId: id, content };
+        yield { type: NodeExecuteState.Attachment, nodeId: id, attachment };
      }
    }
  }
--- a/packages/backend/server/src/plugins/copilot/workflow/executor/chat-text.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/executor/chat-text.ts
@@ -63,26 +63,29 @@ export class CopilotChatTextExecutor extends AutoRegisteredWorkflowExecutor {
    params: Record<string, string>,
    options?: CopilotChatOptions
  ): AsyncIterable<NodeExecuteResult> {
-    const [{ paramKey, id }, prompt, provider] = await this.initExecutor(data);
+    const [{ paramKey, paramToucher, id }, prompt, provider] =
+      await this.initExecutor(data);

    const finalMessage = prompt.finish(params);
+    const config = { ...prompt.config, ...options };
    if (paramKey) {
      // update params with custom key
+      const result = {
+        [paramKey]: await provider.generateText(
+          finalMessage,
+          prompt.model,
+          config
+        ),
+      };
      yield {
        type: NodeExecuteState.Params,
-        params: {
-          [paramKey]: await provider.generateText(
-            finalMessage,
-            prompt.model,
-            options
-          ),
-        },
+        params: paramToucher?.(result) ?? result,
      };
    } else {
      for await (const content of provider.generateTextStream(
        finalMessage,
        prompt.model,
-        options
+        config
      )) {
        yield { type: NodeExecuteState.Content, nodeId: id, content };
      }
--- a/packages/backend/server/src/plugins/copilot/workflow/executor/check-html.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/executor/check-html.ts
@@ -26,7 +26,7 @@ export class CopilotCheckHtmlExecutor extends AutoRegisteredWorkflowExecutor {
  }

  private async checkHtml(
-    content?: string | string[],
+    content?: string | string[] | Record<string, any>,
    strict?: boolean
  ): Promise<boolean> {
    try {
--- a/packages/backend/server/src/plugins/copilot/workflow/executor/check-json.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/executor/check-json.ts
@@ -25,7 +25,9 @@ export class CopilotCheckJsonExecutor extends AutoRegisteredWorkflowExecutor {
    return NodeExecutorType.CheckJson;
  }

-  private checkJson(content?: string | string[]): boolean {
+  private checkJson(
+    content?: string | string[] | Record<string, any>
+  ): boolean {
    try {
      if (content && typeof content === 'string') {
        JSON.parse(content);
--- a/packages/backend/server/src/plugins/copilot/workflow/executor/types.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/executor/types.ts
@@ -14,13 +14,15 @@ export enum NodeExecuteState {
  EndRun,
  Params,
  Content,
+  Attachment,
 }

 export type NodeExecuteResult =
  | { type: NodeExecuteState.StartRun; nodeId: string }
  | { type: NodeExecuteState.EndRun; nextNode?: WorkflowNode }
  | { type: NodeExecuteState.Params; params: WorkflowParams }
-  | { type: NodeExecuteState.Content; nodeId: string; content: string };
+  | { type: NodeExecuteState.Content; nodeId: string; content: string }
+  | { type: NodeExecuteState.Attachment; nodeId: string; attachment: string };

 export abstract class NodeExecutor {
  abstract get type(): NodeExecutorType;
--- a/packages/backend/server/src/plugins/copilot/workflow/graph.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/graph.ts
@@ -1,87 +0,0 @@
-import { NodeExecutorType } from './executor';
-import type { WorkflowGraphs, WorkflowNodeState } from './types';
-import { WorkflowNodeType } from './types';
-
-export const WorkflowGraphList: WorkflowGraphs = [
-  {
-    name: 'presentation',
-    graph: [
-      {
-        id: 'start',
-        name: 'Start: check language',
-        nodeType: WorkflowNodeType.Basic,
-        type: NodeExecutorType.ChatText,
-        promptName: 'workflow:presentation:step1',
-        paramKey: 'language',
-        edges: ['step2'],
-      },
-      {
-        id: 'step2',
-        name: 'Step 2: generate presentation',
-        nodeType: WorkflowNodeType.Basic,
-        type: NodeExecutorType.ChatText,
-        promptName: 'workflow:presentation:step2',
-        edges: ['step3'],
-      },
-      {
-        id: 'step3',
-        name: 'Step 3: format presentation if needed',
-        nodeType: WorkflowNodeType.Decision,
-        condition: (nodeIds: string[], params: WorkflowNodeState) => {
-          const lines = params.content?.split('\n') || [];
-          return nodeIds[
-            Number(
-              !lines.some(line => {
-                try {
-                  if (line.trim()) {
-                    JSON.parse(line);
-                  }
-                  return false;
-                } catch {
-                  return true;
-                }
-              })
-            )
-          ];
-        },
-        edges: ['step4', 'step5'],
-      },
-      {
-        id: 'step4',
-        name: 'Step 4: format presentation',
-        nodeType: WorkflowNodeType.Basic,
-        type: NodeExecutorType.ChatText,
-        promptName: 'workflow:presentation:step4',
-        edges: ['step5'],
-      },
-      {
-        id: 'step5',
-        name: 'Step 5: finish',
-        nodeType: WorkflowNodeType.Nope,
-        edges: [],
-      },
-    ],
-  },
-  {
-    name: 'brainstorm',
-    graph: [
-      {
-        id: 'start',
-        name: 'Start: check language',
-        nodeType: WorkflowNodeType.Basic,
-        type: NodeExecutorType.ChatText,
-        promptName: 'workflow:brainstorm:step1',
-        paramKey: 'language',
-        edges: ['step2'],
-      },
-      {
-        id: 'step2',
-        name: 'Step 2: generate brainstorm mind map',
-        nodeType: WorkflowNodeType.Basic,
-        type: NodeExecutorType.ChatText,
-        promptName: 'workflow:brainstorm:step2',
-        edges: [],
-      },
-    ],
-  },
-];
--- a/packages/backend/server/src/plugins/copilot/workflow/graph/brainstorm.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/graph/brainstorm.ts
@@ -0,0 +1,25 @@
+import { NodeExecutorType } from '../executor';
+import { type WorkflowGraph, WorkflowNodeType } from '../types';
+
+export const brainstorm: WorkflowGraph = {
+  name: 'brainstorm',
+  graph: [
+    {
+      id: 'start',
+      name: 'Start: check language',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:brainstorm:step1',
+      paramKey: 'language',
+      edges: ['step2'],
+    },
+    {
+      id: 'step2',
+      name: 'Step 2: generate brainstorm mind map',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:brainstorm:step2',
+      edges: [],
+    },
+  ],
+};
--- a/packages/backend/server/src/plugins/copilot/workflow/graph/image-filter.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/graph/image-filter.ts
@@ -0,0 +1,183 @@
+import { NodeExecutorType } from '../executor';
+import type { WorkflowGraph, WorkflowParams } from '../types';
+import { WorkflowNodeType } from '../types';
+
+export const sketch: WorkflowGraph = {
+  name: 'image-sketch',
+  graph: [
+    {
+      id: 'start',
+      name: 'Start: extract edge',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatImage,
+      promptName: 'debug:action:fal-teed',
+      paramKey: 'controlnets',
+      paramToucher: params => {
+        if (Array.isArray(params.controlnets)) {
+          const controlnets = params.controlnets.map(image_url => ({
+            path: 'diffusers/controlnet-canny-sdxl-1.0',
+            image_url,
+            start_percentage: 0.1,
+            end_percentage: 0.6,
+          }));
+          return { controlnets } as WorkflowParams;
+        } else {
+          return {};
+        }
+      },
+      edges: ['step2'],
+    },
+    {
+      id: 'step2',
+      name: 'Step 2: generate tags',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:image-sketch:step2',
+      paramKey: 'tags',
+      edges: ['step3'],
+    },
+    {
+      id: 'step3',
+      name: 'Step3: generate image',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatImage,
+      promptName: 'workflow:image-sketch:step3',
+      edges: [],
+    },
+  ],
+};
+
+export const clay: WorkflowGraph = {
+  name: 'image-clay',
+  graph: [
+    {
+      id: 'start',
+      name: 'Start: extract edge',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatImage,
+      promptName: 'debug:action:fal-teed',
+      paramKey: 'controlnets',
+      paramToucher: params => {
+        if (Array.isArray(params.controlnets)) {
+          const controlnets = params.controlnets.map(image_url => ({
+            path: 'diffusers/controlnet-canny-sdxl-1.0',
+            image_url,
+            start_percentage: 0.1,
+            end_percentage: 0.6,
+          }));
+          return { controlnets } as WorkflowParams;
+        } else {
+          return {};
+        }
+      },
+      edges: ['step2'],
+    },
+    {
+      id: 'step2',
+      name: 'Step 2: generate tags',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:image-clay:step2',
+      paramKey: 'tags',
+      edges: ['step3'],
+    },
+    {
+      id: 'step3',
+      name: 'Step3: generate image',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatImage,
+      promptName: 'workflow:image-clay:step3',
+      edges: [],
+    },
+  ],
+};
+
+export const anime: WorkflowGraph = {
+  name: 'image-anime',
+  graph: [
+    {
+      id: 'start',
+      name: 'Start: extract edge',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatImage,
+      promptName: 'debug:action:fal-teed',
+      paramKey: 'controlnets',
+      paramToucher: params => {
+        if (Array.isArray(params.controlnets)) {
+          const controlnets = params.controlnets.map(image_url => ({
+            path: 'diffusers/controlnet-canny-sdxl-1.0',
+            image_url,
+            start_percentage: 0.1,
+            end_percentage: 0.6,
+          }));
+          return { controlnets } as WorkflowParams;
+        } else {
+          return {};
+        }
+      },
+      edges: ['step2'],
+    },
+    {
+      id: 'step2',
+      name: 'Step 2: generate tags',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:image-anime:step2',
+      paramKey: 'tags',
+      edges: ['step3'],
+    },
+    {
+      id: 'step3',
+      name: 'Step3: generate image',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatImage,
+      promptName: 'workflow:image-anime:step3',
+      edges: [],
+    },
+  ],
+};
+
+export const pixel: WorkflowGraph = {
+  name: 'image-pixel',
+  graph: [
+    {
+      id: 'start',
+      name: 'Start: extract edge',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatImage,
+      promptName: 'debug:action:fal-teed',
+      paramKey: 'controlnets',
+      paramToucher: params => {
+        if (Array.isArray(params.controlnets)) {
+          const controlnets = params.controlnets.map(image_url => ({
+            path: 'diffusers/controlnet-canny-sdxl-1.0',
+            image_url,
+            start_percentage: 0.1,
+            end_percentage: 0.6,
+          }));
+          return { controlnets } as WorkflowParams;
+        } else {
+          return {};
+        }
+      },
+      edges: ['step2'],
+    },
+    {
+      id: 'step2',
+      name: 'Step 2: generate tags',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:image-pixel:step2',
+      paramKey: 'tags',
+      edges: ['step3'],
+    },
+    {
+      id: 'step3',
+      name: 'Step3: generate image',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatImage,
+      promptName: 'workflow:image-pixel:step3',
+      edges: [],
+    },
+  ],
+};
--- a/packages/backend/server/src/plugins/copilot/workflow/graph/index.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/graph/index.ts
@@ -0,0 +1,13 @@
+import type { WorkflowGraphs } from '../types';
+import { brainstorm } from './brainstorm';
+import { anime, clay, pixel, sketch } from './image-filter';
+import { presentation } from './presentation';
+
+export const WorkflowGraphList: WorkflowGraphs = [
+  brainstorm,
+  presentation,
+  sketch,
+  clay,
+  anime,
+  pixel,
+];
--- a/packages/backend/server/src/plugins/copilot/workflow/graph/presentation.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/graph/presentation.ts
@@ -0,0 +1,63 @@
+import { NodeExecutorType } from '../executor';
+import type { WorkflowGraph, WorkflowNodeState } from '../types';
+import { WorkflowNodeType } from '../types';
+
+export const presentation: WorkflowGraph = {
+  name: 'presentation',
+  graph: [
+    {
+      id: 'start',
+      name: 'Start: check language',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:presentation:step1',
+      paramKey: 'language',
+      edges: ['step2'],
+    },
+    {
+      id: 'step2',
+      name: 'Step 2: generate presentation',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:presentation:step2',
+      edges: ['step3'],
+    },
+    {
+      id: 'step3',
+      name: 'Step 3: format presentation if needed',
+      nodeType: WorkflowNodeType.Decision,
+      condition: (nodeIds: string[], params: WorkflowNodeState) => {
+        const lines = params.content?.split('\n') || [];
+        return nodeIds[
+          Number(
+            !lines.some(line => {
+              try {
+                if (line.trim()) {
+                  JSON.parse(line);
+                }
+                return false;
+              } catch {
+                return true;
+              }
+            })
+          )
+        ];
+      },
+      edges: ['step4', 'step5'],
+    },
+    {
+      id: 'step4',
+      name: 'Step 4: format presentation',
+      nodeType: WorkflowNodeType.Basic,
+      type: NodeExecutorType.ChatText,
+      promptName: 'workflow:presentation:step4',
+      edges: ['step5'],
+    },
+    {
+      id: 'step5',
+      name: 'Step 5: finish',
+      nodeType: WorkflowNodeType.Nope,
+      edges: [],
+    },
+  ],
+};
--- a/packages/backend/server/src/plugins/copilot/workflow/types.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/types.ts
@@ -16,6 +16,7 @@ export type WorkflowNodeData = { id: string; name: string } & (
      promptName?: string;
      // update the prompt params by output with the custom key
      paramKey?: string;
+      paramToucher?: (params: WorkflowParams) => WorkflowParams;
    }
  | {
      nodeType: WorkflowNodeType.Decision;
@@ -44,5 +45,8 @@ export type WorkflowGraphs = Array<WorkflowGraph>;

 // ===================== executor =====================

-export type WorkflowParams = Record<string, string | string[]>;
+export type WorkflowParams = Record<
+  string,
+  string | string[] | Record<string, any>
+>;
 export type WorkflowNodeState = Record<string, string>;
--- a/packages/backend/server/src/plugins/copilot/workflow/workflow.ts
+++ b/packages/backend/server/src/plugins/copilot/workflow/workflow.ts
@@ -9,12 +9,14 @@ import { WorkflowNodeType } from './types';
 export enum GraphExecutorState {
  EnterNode = 'EnterNode',
  EmitContent = 'EmitContent',
+  EmitAttachment = 'EmitAttachment',
  ExitNode = 'ExitNode',
 }

 export type GraphExecutorStatus = { status: GraphExecutorState } & (
  | { status: GraphExecutorState.EnterNode; node: WorkflowNode }
  | { status: GraphExecutorState.EmitContent; content: string }
+  | { status: GraphExecutorState.EmitAttachment; attachment: string }
  | { status: GraphExecutorState.ExitNode; node: WorkflowNode }
 );

@@ -66,6 +68,15 @@ export class WorkflowGraphExecutor {
          } else {
            result += ret.content;
          }
+        } else if (
+          ret.type === NodeExecuteState.Attachment &&
+          !currentNode.hasEdges
+        ) {
+          // pass through content as a stream response if node is end node
+          yield {
+            status: GraphExecutorState.EmitAttachment,
+            attachment: ret.attachment,
+          };
        }
      }