feat(tools): support middlware in dotprompt export

genkit-tools/common/src/server/router.ts

@@ -149,6 +149,7 @@ export const TOOLS_SERVER_ROUTER = (manager: BaseRuntimeManager) =>
           model: input.model.replace('/model/', ''),
           config: input.config,
           tools: input.tools?.map((toolDefinition) => toolDefinition.name),
+          use: input.use,
         };
         return fromMessages(frontmatter, input.messages);
       }),

genkit-tools/common/src/types/apis.ts

@@ -22,6 +22,7 @@ import {
   InferenceDatasetSchema,
 } from './eval';
 import { LogRecordSchema } from './log';
+import { MiddlewareRefSchema } from './middleware';
 import {
   GenerationCommonConfigSchema,
   MessageSchema,
@@ -170,6 +171,7 @@ export const CreatePromptRequestSchema = z.object({
   messages: z.array(MessageSchema),
   config: GenerationCommonConfigSchema.passthrough().optional(),
   tools: z.array(ToolDefinitionSchema).optional(),
+  use: z.array(MiddlewareRefSchema).optional(),
 });
 
 export type CreatePromptRequest = z.infer<typeof CreatePromptRequestSchema>;

genkit-tools/common/src/types/prompt.ts

@@ -20,6 +20,7 @@
 //
 
 import { z } from 'zod';
+import { MiddlewareRefSchema } from './middleware';
 import { GenerationCommonConfigSchema } from './model';
 
 /**
@@ -30,6 +31,7 @@ export const PromptFrontmatterSchema = z.object({
   variant: z.string().optional(),
   model: z.string().optional(),
   tools: z.array(z.string()).optional(),
+  use: z.array(MiddlewareRefSchema).optional(),
   candidates: z.number().optional(),
   config: GenerationCommonConfigSchema.passthrough().optional(),
   input: z

genkit-tools/common/src/utils/prompt.ts

@@ -22,30 +22,115 @@ export function fromMessages(
   frontmatter: PromptFrontmatter,
   messages: MessageData[]
 ): string {
-  let renderedMessages = '';
+  const cleanFrontmatter = cleanupFrontmatter(frontmatter);
+  const { rendered: renderedMessages, anyOmitted } = renderMessages(messages);
+
+  const header = `---
+${stringify(cleanFrontmatter, {
+  collectionStyle: 'block',
+  aliasDuplicateObjects: false,
+}).trim()}
+---`;
+
+  if (anyOmitted) {
+    return (
+      `${header}
+
+{{! Some advanced message types, such as tool requests/responses, have been omitted from the history. See comments inline for more details. }}
+
+${renderedMessages}`.trimEnd() + '\n'
+    );
+  }
+
+  return (
+    `${header}
+
+${renderedMessages}`.trimEnd() + '\n'
+  );
+}
+
+/**
+ * Renders an array of message data into a Dotprompt template string.
+ */
+function renderMessages(messages: MessageData[]): {
+  rendered: string;
+  anyOmitted: boolean;
+} {
+  let anyOmitted = false;
+  let rendered = '';
+
   messages.forEach((message) => {
-    renderedMessages += `{{role "${message.role}"}}\n`;
-    renderedMessages += message.content.map(partToString);
-    renderedMessages += '\n\n';
+    const hasToolRequest = message.content.some((p) => 'toolRequest' in p);
+    const hasToolResponse = message.content.some((p) => 'toolResponse' in p);
+    const hasSupportedPart =
+      message.content.length === 0 ||
+      message.content.some((p) => 'text' in p || 'media' in p);
+    const hasUnsupportedPart = message.content.some(
+      (p) => !('text' in p) && !('media' in p)
+    );
+
+    if (hasToolRequest || hasToolResponse || !hasSupportedPart) {
+      anyOmitted = true;
+      let reason = 'unsupported content';
+      if (hasToolRequest) {
+        reason = 'toolRequest';
+      } else if (hasToolResponse) {
+        reason = 'toolResponse';
+      }
+      rendered += `{{! message with role "${message.role}" omitted (${reason}). }}\n\n`;
+    } else {
+      if (hasUnsupportedPart) {
+        anyOmitted = true;
+      }
+      rendered += `{{role "${message.role}"}}\n`;
+      rendered += message.content.map(partToString).join('');
+      rendered += '\n\n';
+    }
   });
 
-  return `---
-${stringify(frontmatter)}
----
+  return { rendered, anyOmitted };
+}
+
+/**
+ * Removes empty arrays, empty objects, and null/undefined values from the
+ * frontmatter to ensure the generated YAML is clean and idiomatic.
+ */
+function cleanupFrontmatter(frontmatter: PromptFrontmatter): any {
+  return recursiveCleanup(frontmatter) || {};
+}
 
-${renderedMessages}`;
+function recursiveCleanup(val: any): any {
+  if (Array.isArray(val)) {
+    const cleaned = val
+      .map(recursiveCleanup)
+      .filter((v) => v !== undefined && v !== null);
+    return cleaned.length > 0 ? cleaned : undefined;
+  }
+  if (val !== null && typeof val === 'object' && !(val instanceof Date)) {
+    const cleaned: any = {};
+    let hasProps = false;
+    for (const key in val) {
+      const v = recursiveCleanup(val[key]);
+      if (v !== undefined && v !== null) {
+        cleaned[key] = v;
+        hasProps = true;
+      }
+    }
+    return hasProps ? cleaned : undefined;
+  }
+  return val === null || val === undefined ? undefined : val;
 }
 
 function partToString(part: Part): string {
-  if (part.text) {
+  if ('text' in part && part.text !== undefined) {
     return part.text;
-  } else if (part.media) {
+  } else if ('media' in part && part.media !== undefined) {
     return `{{media url:${part.media.url}}}`;
-  } else if (part.toolRequest) {
-    return '<< tool request omitted >>';
-  } else if (part.toolResponse) {
-    return '<< tool response omitted >>';
-  } else {
-    return '';
   }
+
+  const type =
+    Object.keys(part).find(
+      (k) => k !== 'metadata' && part[k as keyof Part] !== undefined
+    ) || 'unknown';
+  return `{{! ${type} part omitted }}`;
 }

genkit-tools/common/tests/utils/prompt_test.ts

@@ -44,16 +44,141 @@ describe('fromMessages', () => {
       'model: googleai/gemini-pro\n' +
       'config:\n' +
       '  temperature: 0.5\n' +
-      '\n' +
       '---\n' +
       '\n' +
       '{{role "user"}}\n' +
       'Who are you?\n' +
       '\n' +
       '{{role "model"}}\n' +
-      'I am Oz -- the Great and Powerful.,' +
-      '{{media url:https://example.com/image.jpg}}\n' +
-      '\n';
+      'I am Oz -- the Great and Powerful.{{media url:https://example.com/image.jpg}}\n';
+    expect(fromMessages(frontmatter, messages)).toStrictEqual(expected);
+  });
+
+  it('handles toolRequest by omitting the entire message', () => {
+    const frontmatter: PromptFrontmatter = {
+      model: 'googleai/gemini-pro',
+      use: [{ name: 'test-middleware', config: { foo: 'bar' } }],
+    };
+    const messages: MessageData[] = [
+      {
+        role: 'user',
+        content: [
+          { text: 'Hello' },
+          { reasoning: 'Thinking...' } as any,
+          { toolRequest: { name: 'myTool' } } as any,
+        ],
+      },
+    ];
+
+    const expected =
+      '---\n' +
+      'model: googleai/gemini-pro\n' +
+      'use:\n' +
+      '  - name: test-middleware\n' +
+      '    config:\n' +
+      '      foo: bar\n' +
+      '---\n' +
+      '\n' +
+      '{{! Some advanced message types, such as tool requests/responses, have been omitted from the history. See comments inline for more details. }}\n' +
+      '\n' +
+      '{{! message with role "user" omitted (toolRequest). }}\n';
+
+    expect(fromMessages(frontmatter, messages)).toStrictEqual(expected);
+  });
+
+  it('omits messages entirely composed of unsupported parts', () => {
+    const frontmatter: PromptFrontmatter = { model: 'model' };
+    const messages: MessageData[] = [
+      {
+        role: 'model',
+        content: [
+          { toolResponse: { name: 'myTool', output: 'result' } } as any,
+        ],
+      },
+    ];
+
+    const expected =
+      '---\n' +
+      'model: model\n' +
+      '---\n' +
+      '\n' +
+      '{{! Some advanced message types, such as tool requests/responses, have been omitted from the history. See comments inline for more details. }}\n' +
+      '\n' +
+      '{{! message with role "model" omitted (toolResponse). }}\n';
+
+    expect(fromMessages(frontmatter, messages)).toStrictEqual(expected);
+  });
+
+  it('omits messages composed of other unsupported parts with "unsupported content" reason', () => {
+    const frontmatter: PromptFrontmatter = { model: 'model' };
+    const messages: MessageData[] = [
+      {
+        role: 'model',
+        content: [{ reasoning: 'Thinking...' } as any],
+      },
+    ];
+
+    const expected =
+      '---\n' +
+      'model: model\n' +
+      '---\n' +
+      '\n' +
+      '{{! Some advanced message types, such as tool requests/responses, have been omitted from the history. See comments inline for more details. }}\n' +
+      '\n' +
+      '{{! message with role "model" omitted (unsupported content). }}\n';
+
+    expect(fromMessages(frontmatter, messages)).toStrictEqual(expected);
+  });
+
+  it('handles mixed support messages without toolRequest by commenting parts', () => {
+    const frontmatter: PromptFrontmatter = { model: 'model' };
+    const messages: MessageData[] = [
+      {
+        role: 'user',
+        content: [
+          { text: 'Here is data: ' },
+          { data: { foo: 'bar' } } as any,
+          { text: ' and more text.' },
+        ],
+      },
+    ];
+
+    const expected =
+      '---\n' +
+      'model: model\n' +
+      '---\n' +
+      '\n' +
+      '{{! Some advanced message types, such as tool requests/responses, have been omitted from the history. See comments inline for more details. }}\n' +
+      '\n' +
+      '{{role "user"}}\n' +
+      'Here is data: {{! data part omitted }} and more text.\n';
+
+    expect(fromMessages(frontmatter, messages)).toStrictEqual(expected);
+  });
+
+  it('recursively cleans empty objects and arrays from frontmatter', () => {
+    const frontmatter: any = {
+      model: 'googleai/gemini-pro',
+      use: [
+        {
+          name: 'fallback',
+          config: {},
+        },
+      ],
+      tools: [],
+      config: {
+        safetySettings: [],
+      },
+    };
+    const messages: any[] = [];
+
+    const expected =
+      '---\n' +
+      'model: googleai/gemini-pro\n' +
+      'use:\n' +
+      '  - name: fallback\n' +
+      '---\n';
+
     expect(fromMessages(frontmatter, messages)).toStrictEqual(expected);
   });
 });