fix(FlowiseChatGoogleGenerativeAI): handle 'thinking' content type round-trip

packages/components/nodes/chatmodels/ChatGoogleGenerativeAI/FlowiseChatGoogleGenerativeAI.test.ts

@@ -0,0 +1,98 @@
+import { AIMessage } from '@langchain/core/messages'
+import { convertMessageContentToParts } from './FlowiseChatGoogleGenerativeAI'
+
+describe('convertMessageContentToParts — Gemini "thinking" content blocks', () => {
+    // Background: When a Gemini model with thinking enabled
+    // (gemini-2.5-* with thinkingConfig, gemini-3-flash-preview, etc.)
+    // emits a thought summary, Flowise's response parser stores it as a
+    // LangChain content block of shape:
+    //
+    //   { type: 'thinking', thinking: 'reasoning text…', signature: '…' }
+    //
+    // On the NEXT iteration of an agent loop, the assistant message is
+    // echoed back to the API as conversation history, and each content
+    // block runs through `_convertLangChainContentToPart`. Without a
+    // branch for type='thinking', the converter throws
+    // "Unknown content type thinking" and the agent node errors out.
+    //
+    // Google's native shape is a text Part with a boolean `thought: true`
+    // flag and an optional `thoughtSignature` for Gemini-3 tool-call
+    // signature continuity. See:
+    //   https://ai.google.dev/gemini-api/docs/thinking
+    //   https://ai.google.dev/gemini-api/docs/thought-signatures
+
+    it('round-trips a thinking content block back into a Gemini text Part with thought=true', () => {
+        const msg = new AIMessage({
+            content: [
+                { type: 'thinking', thinking: 'First I should validate the inputs.' } as any,
+                { type: 'text', text: 'OK, validated.' }
+            ]
+        })
+
+        const parts = convertMessageContentToParts(msg, false, [])
+
+        const thoughtPart = parts.find((p: any) => p.thought === true) as any
+        expect(thoughtPart).toBeDefined()
+        expect(thoughtPart.text).toBe('First I should validate the inputs.')
+        expect(thoughtPart.thought).toBe(true)
+        // No signature in the input → no thoughtSignature in the output
+        expect(thoughtPart.thoughtSignature).toBeUndefined()
+
+        const textPart = parts.find((p: any) => p.text === 'OK, validated.' && !p.thought) as any
+        expect(textPart).toBeDefined()
+    })
+
+    it('preserves the thoughtSignature for Gemini-3 multi-turn tool-call continuity', () => {
+        // signature is stored under `signature` on the LangChain block (see
+        // the response parsers' output in FlowiseChatGoogleGenerativeAI.ts);
+        // it must be emitted as `thoughtSignature` on the outgoing Part.
+        const msg = new AIMessage({
+            content: [
+                {
+                    type: 'thinking',
+                    thinking: 'Need to call the search tool.',
+                    signature: 'abc123-thought-sig'
+                } as any
+            ]
+        })
+
+        const parts = convertMessageContentToParts(msg, false, [])
+        const p = parts[0] as any
+        expect(p.thought).toBe(true)
+        expect(p.thoughtSignature).toBe('abc123-thought-sig')
+    })
+
+    it('also accepts thoughtSignature on the LangChain block (alternate key name)', () => {
+        const msg = new AIMessage({
+            content: [
+                {
+                    type: 'thinking',
+                    thinking: 'alt',
+                    thoughtSignature: 'sig-from-alt-key'
+                } as any
+            ]
+        })
+
+        const parts = convertMessageContentToParts(msg, false, [])
+        const p = parts[0] as any
+        expect(p.thought).toBe(true)
+        expect(p.thoughtSignature).toBe('sig-from-alt-key')
+    })
+
+    it('coerces non-string thinking payload to a string instead of throwing', () => {
+        const msg = new AIMessage({
+            content: [{ type: 'thinking', thinking: null } as any]
+        })
+        const parts = convertMessageContentToParts(msg, false, [])
+        const p = parts[0] as any
+        expect(p.thought).toBe(true)
+        expect(typeof p.text).toBe('string')
+    })
+
+    it('still throws "Unknown content type" for truly unrecognized types', () => {
+        const msg = new AIMessage({
+            content: [{ type: 'definitely-not-a-real-type', value: 1 } as any]
+        })
+        expect(() => convertMessageContentToParts(msg, false, [])).toThrow(/Unknown content type/)
+    })
+})

packages/components/nodes/chatmodels/ChatGoogleGenerativeAI/FlowiseChatGoogleGenerativeAI.ts

@@ -302,6 +302,29 @@ function _convertLangChainContentToPart(content: MessageContentComplex, isMultim
         }
     } else if ('functionCall' in content) {
         return undefined
+    } else if (content.type === 'thinking') {
+        // Gemini's "thinking" / "thought summary" parts. Created by the
+        // response parsers in this file (see the two locations that emit
+        // `{ type: 'thinking' as const, thinking: p.text, signature: ... }`).
+        // When the assistant message is echoed back to the API as
+        // conversation history, the part must be in Google's native
+        // shape — a regular text Part with `thought: true` (and the
+        // optional `thoughtSignature` Gemini 3 expects for tool-call
+        // continuity). Without this branch the converter falls through
+        // to the throwing else, surfacing as
+        // "Error in Agent node: Unknown content type thinking" on the
+        // SECOND iteration of any agent loop running on a thinking
+        // model (gemini-2.5-* with thinking, gemini-3-flash-preview, …).
+        //
+        // Schema reference: https://ai.google.dev/gemini-api/docs/thinking
+        // Signature reference: https://ai.google.dev/gemini-api/docs/thought-signatures
+        const text = (content as any).thinking ?? (content as any).text ?? ''
+        const signature = (content as any).signature ?? (content as any).thoughtSignature
+        return {
+            text: typeof text === 'string' ? text : String(text ?? ''),
+            thought: true,
+            ...(signature ? { thoughtSignature: signature } : {})
+        } as Part
     } else {
         if ('type' in content) {
             throw new Error(`Unknown content type ${content.type}`)