fix(a2a): added file data part and data data part to a2a agents (#2805)

* fix(a2a): added file data part and data data part to a2a agents

* removed unused streaming tool

* ack comment

Author: waleedlatif1

apps/docs/content/docs/en/tools/a2a.mdx

@@ -44,6 +44,8 @@ Send a message to an external A2A-compatible agent.
 | `message` | string | Yes | Message to send to the agent |
 | `taskId` | string | No | Task ID for continuing an existing task |
 | `contextId` | string | No | Context ID for conversation continuity |
+| `data` | string | No | Structured data to include with the message \(JSON string\) |
+| `files` | array | No | Files to include with the message |
 | `apiKey` | string | No | API key for authentication |
 
 #### Output

apps/sim/app/api/tools/a2a/send-message-stream/route.ts

@@ -1,4 +1,4 @@
-import type { Message, Task } from '@a2a-js/sdk'
+import type { DataPart, FilePart, Message, Part, Task, TextPart } from '@a2a-js/sdk'
 import { createLogger } from '@sim/logger'
 import { type NextRequest, NextResponse } from 'next/server'
 import { z } from 'zod'
@@ -10,11 +10,20 @@ export const dynamic = 'force-dynamic'
 
 const logger = createLogger('A2ASendMessageAPI')
 
+const FileInputSchema = z.object({
+  type: z.enum(['file', 'url']),
+  data: z.string(),
+  name: z.string(),
+  mime: z.string().optional(),
+})
+
 const A2ASendMessageSchema = z.object({
   agentUrl: z.string().min(1, 'Agent URL is required'),
   message: z.string().min(1, 'Message is required'),
   taskId: z.string().optional(),
   contextId: z.string().optional(),
+  data: z.string().optional(),
+  files: z.array(FileInputSchema).optional(),
   apiKey: z.string().optional(),
 })
 
@@ -51,18 +60,100 @@ export async function POST(request: NextRequest) {
       hasContextId: !!validatedData.contextId,
     })
 
-    const client = await createA2AClient(validatedData.agentUrl, validatedData.apiKey)
+    let client
+    try {
+      client = await createA2AClient(validatedData.agentUrl, validatedData.apiKey)
+      logger.info(`[${requestId}] A2A client created successfully`)
+    } catch (clientError) {
+      logger.error(`[${requestId}] Failed to create A2A client:`, clientError)
+      return NextResponse.json(
+        {
+          success: false,
+          error: `Failed to connect to agent: ${clientError instanceof Error ? clientError.message : 'Unknown error'}`,
+        },
+        { status: 502 }
+      )
+    }
+
+    const parts: Part[] = []
+
+    const textPart: TextPart = { kind: 'text', text: validatedData.message }
+    parts.push(textPart)
+
+    if (validatedData.data) {
+      try {
+        const parsedData = JSON.parse(validatedData.data)
+        const dataPart: DataPart = { kind: 'data', data: parsedData }
+        parts.push(dataPart)
+      } catch (parseError) {
+        logger.warn(`[${requestId}] Failed to parse data as JSON, skipping DataPart`, {
+          error: parseError instanceof Error ? parseError.message : String(parseError),
+        })
+      }
+    }
+
+    if (validatedData.files && validatedData.files.length > 0) {
+      for (const file of validatedData.files) {
+        if (file.type === 'url') {
+          const filePart: FilePart = {
+            kind: 'file',
+            file: {
+              name: file.name,
+              mimeType: file.mime,
+              uri: file.data,
+            },
+          }
+          parts.push(filePart)
+        } else if (file.type === 'file') {
+          let bytes = file.data
+          let mimeType = file.mime
+
+          if (file.data.startsWith('data:')) {
+            const match = file.data.match(/^data:([^;]+);base64,(.+)$/)
+            if (match) {
+              mimeType = mimeType || match[1]
+              bytes = match[2]
+            } else {
+              bytes = file.data
+            }
+          }
+
+          const filePart: FilePart = {
+            kind: 'file',
+            file: {
+              name: file.name,
+              mimeType: mimeType || 'application/octet-stream',
+              bytes,
+            },
+          }
+          parts.push(filePart)
+        }
+      }
+    }
 
     const message: Message = {
       kind: 'message',
       messageId: crypto.randomUUID(),
       role: 'user',
-      parts: [{ kind: 'text', text: validatedData.message }],
+      parts,
       ...(validatedData.taskId && { taskId: validatedData.taskId }),
       ...(validatedData.contextId && { contextId: validatedData.contextId }),
     }
 
-    const result = await client.sendMessage({ message })
+    let result
+    try {
+      result = await client.sendMessage({ message })
+      logger.info(`[${requestId}] A2A sendMessage completed`, { resultKind: result?.kind })
+    } catch (sendError) {
+      logger.error(`[${requestId}] Failed to send A2A message:`, sendError)
+      return NextResponse.json(
+        {
+          success: false,
+          error: `Failed to send message: ${sendError instanceof Error ? sendError.message : 'Unknown error'}`,
+        },
+        { status: 502 }
+      )
+    }
 
     if (result.kind === 'message') {
       const responseMessage = result as Message

apps/sim/app/api/tools/a2a/send-message/route.ts

@@ -98,6 +98,23 @@ export const A2ABlock: BlockConfig<A2AResponse> = {
       condition: { field: 'operation', value: 'a2a_send_message' },
       required: true,
     },
+    {
+      id: 'data',
+      title: 'Data (JSON)',
+      type: 'code',
+      placeholder: '{\n  "key": "value"\n}',
+      description: 'Structured data to include with the message (DataPart)',
+      condition: { field: 'operation', value: 'a2a_send_message' },
+    },
+    {
+      id: 'files',
+      title: 'Files',
+      type: 'file-upload',
+      placeholder: 'Upload files to send',
+      description: 'Files to include with the message (FilePart)',
+      condition: { field: 'operation', value: 'a2a_send_message' },
+      multiple: true,
+    },
     {
       id: 'taskId',
       title: 'Task ID',
@@ -208,6 +225,14 @@ export const A2ABlock: BlockConfig<A2AResponse> = {
       type: 'string',
       description: 'Context ID for conversation continuity',
     },
+    data: {
+      type: 'json',
+      description: 'Structured data to include with the message',
+    },
+    files: {
+      type: 'array',
+      description: 'Files to include with the message',
+    },
     historyLength: {
       type: 'number',
       description: 'Number of history messages to include',

apps/sim/blocks/blocks/a2a.ts

@@ -36,9 +36,10 @@ class ApiKeyInterceptor implements CallInterceptor {
 /**
  * Create an A2A client from an agent URL with optional API key authentication
  *
- * The agent URL should be the full endpoint URL (e.g., /api/a2a/serve/{agentId}).
- * We pass an empty path to createFromUrl so it uses the URL directly for agent card
- * discovery (GET on the URL) instead of appending .well-known/agent-card.json.
+ * Supports both standard A2A agents (agent card at /.well-known/agent.json)
+ * and Sim Studio agents (agent card at root URL via GET).
+ *
+ * Tries standard path first, falls back to root URL for compatibility.
  */
 export async function createA2AClient(agentUrl: string, apiKey?: string): Promise<Client> {
   const factoryOptions = apiKey
@@ -49,6 +50,18 @@ export async function createA2AClient(agentUrl: string, apiKey?: string): Promis
       })
     : ClientFactoryOptions.default
   const factory = new ClientFactory(factoryOptions)
+
+  // Try standard A2A path first (/.well-known/agent.json)
+  try {
+    return await factory.createFromUrl(agentUrl, '/.well-known/agent.json')
+  } catch (standardError) {
+    logger.debug('Standard agent card path failed, trying root URL', {
+      agentUrl,
+      error: standardError instanceof Error ? standardError.message : String(standardError),
+    })
+  }
+
+  // Fall back to root URL (Sim Studio compatibility)
   return factory.createFromUrl(agentUrl, '')
 }
 

apps/sim/lib/a2a/utils.ts

@@ -30,11 +30,14 @@ export const a2aCancelTaskTool: ToolConfig<A2ACancelTaskParams, A2ACancelTaskRes
     headers: () => ({
       'Content-Type': 'application/json',
     }),
-    body: (params: A2ACancelTaskParams) => ({
-      agentUrl: params.agentUrl,
-      taskId: params.taskId,
-      apiKey: params.apiKey,
-    }),
+    body: (params: A2ACancelTaskParams) => {
+      const body: Record<string, string> = {
+        agentUrl: params.agentUrl,
+        taskId: params.taskId,
+      }
+      if (params.apiKey) body.apiKey = params.apiKey
+      return body
+    },
   },
 
   transformResponse: async (response: Response) => {