fix(workflows): accept json input type and return 400 for unsupported input types

apps/sim/executor/utils/start-block.test.ts

@@ -430,6 +430,7 @@ describe('start-block utilities', () => {
             value: [
               { name: 'count', type: 'number' },
               { name: 'payload', type: 'object' },
+              { name: 'meta', type: 'json' },
             ],
           },
         },
@@ -446,12 +447,14 @@ describe('start-block utilities', () => {
         workflowInput: {
           count: '5',
           payload: '{"event":"push"}',
+          meta: '{"source":"api"}',
           extra: 'untouched',
         },
       })
 
       expect(output.count).toBe(5)
       expect(output.payload).toEqual({ event: 'push' })
+      expect(output.meta).toEqual({ source: 'api' })
       expect(output.extra).toBe('untouched')
     })
   })

apps/sim/executor/utils/start-block.ts

@@ -7,6 +7,7 @@ import {
   isInternalFileUrl,
   parseInternalFileUrl,
 } from '@/lib/uploads/utils/file'
+import { canonicalInputFormatFieldType } from '@/lib/workflows/input-format-schema'
 import {
   classifyStartBlockType,
   resolveStartCandidates,
@@ -245,7 +246,7 @@ export function coerceValue(type: string | null | undefined, value: unknown): un
     return value
   }
 
-  switch (type) {
+  switch (type ? (canonicalInputFormatFieldType(type) ?? type) : type) {
     case 'string':
       return typeof value === 'string' ? value : String(value)
     case 'number': {

apps/sim/lib/mcp/orchestration/workflow-mcp-lifecycle.test.ts

@@ -11,11 +11,13 @@ vi.mock('@/lib/mcp/workflow-mcp-sync', () => ({
   generateParameterSchemaForWorkflow: vi.fn().mockResolvedValue({ type: 'object', properties: {} }),
 }))
 
+import { OrchestrationError } from '@/lib/core/orchestration/types'
 import { MAX_MCP_PARAMETER_SCHEMA_BYTES, MAX_MCP_TOOLS_PER_SERVER } from '@/lib/mcp/constants'
 import {
   performCreateWorkflowMcpServer,
   performUpdateWorkflowMcpTool,
 } from '@/lib/mcp/orchestration/workflow-mcp-lifecycle'
+import { generateParameterSchemaForWorkflow } from '@/lib/mcp/workflow-mcp-sync'
 import { hasValidStartBlock } from '@/lib/workflows/triggers/utils.server'
 
 describe('workflow MCP lifecycle orchestration', () => {
@@ -97,6 +99,36 @@ describe('workflow MCP lifecycle orchestration', () => {
     expect(dbChainMockFns.insert).not.toHaveBeenCalled()
   })
 
+  it('answers an unpublishable workflow input as a validation failure naming the field', async () => {
+    const message =
+      'Workflow input "payload" has unsupported type "integer". Use one of: string, number.'
+    vi.mocked(hasValidStartBlock).mockResolvedValueOnce(true)
+    vi.mocked(generateParameterSchemaForWorkflow).mockRejectedValueOnce(
+      new OrchestrationError('validation', message)
+    )
+    dbChainMockFns.where.mockResolvedValueOnce([
+      {
+        id: 'wf-1',
+        name: 'Workflow',
+        description: null,
+        isDeployed: true,
+        workspaceId: 'workspace-1',
+        deployedAt: new Date('2026-01-01T00:00:00Z'),
+        updatedAt: new Date('2026-01-01T00:00:00Z'),
+      },
+    ])
+
+    const result = await performCreateWorkflowMcpServer({
+      workspaceId: 'workspace-1',
+      userId: 'user-1',
+      name: 'Server',
+      workflowIds: ['wf-1'],
+    })
+
+    expect(result).toEqual({ success: false, error: message, errorCode: 'validation' })
+    expect(dbChainMockFns.insert).not.toHaveBeenCalled()
+  })
+
   it('rejects workflow MCP server fan-out above the per-workflow limit', async () => {
     vi.mocked(hasValidStartBlock).mockResolvedValueOnce(true)
     dbChainMockFns.where.mockResolvedValueOnce([

apps/sim/lib/mcp/orchestration/workflow-mcp-lifecycle.ts

@@ -3,6 +3,7 @@ import { db, workflow, workflowMcpServer, workflowMcpTool } from '@sim/db'
 import { createLogger } from '@sim/logger'
 import { generateId } from '@sim/utils/id'
 import { and, asc, eq, inArray, isNull, ne, sql } from 'drizzle-orm'
+import { OrchestrationError } from '@/lib/core/orchestration/types'
 import type { DbOrTx } from '@/lib/db/types'
 import {
   MAX_MCP_SERVER_PARAMETER_SCHEMAS_BYTES,
@@ -232,7 +233,14 @@ async function prepareWorkflowMcpTool(params: {
   const toolDescription =
     params.toolDescription !== undefined ? params.toolDescription?.trim() || null : null
 
-  const baseSchema = await generateParameterSchemaForWorkflow(workflowRecord.id)
+  const baseSchema = await generateParameterSchemaForWorkflow(workflowRecord.id).catch(
+    (error: unknown) => {
+      if (error instanceof OrchestrationError && error.code === 'validation') {
+        throw new WorkflowMcpExpectedError(error.message, 'validation')
+      }
+      throw error
+    }
+  )
   const requestedOverrides =
     params.parameterDescriptionOverrides ??
     (params.legacyParameterSchema

apps/sim/lib/workflows/editing/validation.test.ts

@@ -345,6 +345,37 @@ describe('validateInputsForBlock', () => {
     ).toBe(false)
   })
 
+  describe('input-format', () => {
+    const config = { id: 'inputFormat', type: 'input-format' as const }
+    const validate = (value: unknown) =>
+      validateValueForSubBlockType(config, value, 'inputFormat', 'start_trigger', 'start-1')
+
+    it('stores type aliases as their canonical type and keeps untyped rows', () => {
+      expect(
+        validate([
+          { name: 'payload', type: 'json' },
+          { name: 'documents', type: 'files' },
+          { name: 'message' },
+        ])
+      ).toEqual({
+        valid: true,
+        value: [
+          { name: 'payload', type: 'object' },
+          { name: 'documents', type: 'file[]' },
+          { name: 'message' },
+        ],
+      })
+    })
+
+    it('rejects a type no workflow input can declare, listing the allowed types', () => {
+      const result = validate([{ name: 'count', type: 'integer' }])
+      expect(result.valid).toBe(false)
+      expect(result.error?.error).toBe(
+        'Invalid type "integer" for inputFormat[0] - use one of: string, number, boolean, object, array, file[]'
+      )
+    })
+  })
+
   describe('model-fallback-list', () => {
     const config = { id: 'fallbackModels', type: 'model-fallback-list' as const }
     const validate = (value: unknown) =>

apps/sim/lib/workflows/editing/validation.ts

@@ -24,6 +24,10 @@ import {
   type SelectorReference,
   validateSelectorIds,
 } from '@/lib/workflows/editing/selector-validator'
+import {
+  canonicalInputFormatFieldType,
+  INPUT_FORMAT_FIELD_TYPES,
+} from '@/lib/workflows/input-format-schema'
 import { containsReference } from '@/lib/workflows/sanitization/references'
 import { getSkillById } from '@/lib/workflows/skills/operations'
 import {
@@ -639,7 +643,44 @@ export function validateValueForSubBlockType(
       return { valid: true, value }
     }
 
-    case 'input-format':
+    case 'input-format': {
+      if (!Array.isArray(value)) {
+        return {
+          valid: false,
+          error: {
+            blockId,
+            blockType,
+            field: fieldName,
+            value,
+            error: `Invalid ${type} value for field "${fieldName}" - expected an array`,
+          },
+        }
+      }
+      const rows: unknown[] = []
+      for (const [index, row] of value.entries()) {
+        if (!isPlainRecord(row) || row.type === undefined) {
+          rows.push(row)
+          continue
+        }
+        const fieldType =
+          typeof row.type === 'string' ? canonicalInputFormatFieldType(row.type) : null
+        if (!fieldType) {
+          return {
+            valid: false,
+            error: {
+              blockId,
+              blockType,
+              field: fieldName,
+              value,
+              error: `Invalid type ${JSON.stringify(row.type)} for ${fieldName}[${index}] - use one of: ${INPUT_FORMAT_FIELD_TYPES.join(', ')}`,
+            },
+          }
+        }
+        rows.push(fieldType === row.type ? row : { ...row, type: fieldType })
+      }
+      return { valid: true, value: rows }
+    }
+
     case 'table': {
       // Should be an array
       if (!Array.isArray(value)) {

apps/sim/lib/workflows/input-format-schema.ts

@@ -1,10 +1,44 @@
 import { z } from 'zod'
 
+/** The input field types the editor offers and workflow runs accept. */
+export const INPUT_FORMAT_FIELD_TYPES = [
+  'string',
+  'number',
+  'boolean',
+  'object',
+  'array',
+  'file[]',
+] as const
+
+export type InputFormatFieldType = (typeof INPUT_FORMAT_FIELD_TYPES)[number]
+
+/**
+ * Every spelling a stored field's `type` may use, mapped to its canonical type:
+ * `json` is the name blocks use for object params and outputs, `files` the
+ * legacy MCP alias.
+ */
+const INPUT_FORMAT_FIELD_TYPES_BY_NAME = new Map<string, InputFormatFieldType>([
+  ...INPUT_FORMAT_FIELD_TYPES.map((type) => [type, type] as const),
+  ['json', 'object'],
+  ['files', 'file[]'],
+])
+
+/**
+ * Resolves a stored field's `type` to its canonical type, or `null` when it
+ * names none. A field without a type is a string field.
+ */
+export function canonicalInputFormatFieldType(
+  type: string | undefined
+): InputFormatFieldType | null {
+  if (type === undefined) return 'string'
+  return INPUT_FORMAT_FIELD_TYPES_BY_NAME.get(type) ?? null
+}
+
 /** Stored fields shared by the input editor and catalog authoring contract. */
 export const inputFormatFieldStateSchema = z.object({
   id: z.string(),
   name: z.string(),
-  type: z.enum(['string', 'number', 'boolean', 'object', 'array', 'file[]']),
+  type: z.enum(INPUT_FORMAT_FIELD_TYPES),
   value: z.string(),
   description: z.string().optional(),
   collapsed: z.boolean(),

apps/sim/lib/workflows/input-format.ts

@@ -1,6 +1,9 @@
 import { generateId } from '@sim/utils/id'
 import { isInternalFileUrl, parseInternalFileUrl } from '@/lib/uploads/utils/file'
-import type { InputFormatFieldState } from '@/lib/workflows/input-format-schema'
+import {
+  canonicalInputFormatFieldType,
+  type InputFormatFieldState,
+} from '@/lib/workflows/input-format-schema'
 import { isInputDefinitionTrigger } from '@/lib/workflows/triggers/input-definition-triggers'
 import type { InputFormatField } from '@/lib/workflows/types'
 import type { UserFile } from '@/executor/types'
@@ -48,7 +51,7 @@ export function createDefaultInputFormatField(): InputFormatFieldState {
 
 /** Whether a field is a canonical file array or its legacy MCP alias. */
 export function isFileFieldType(type: string | null | undefined): boolean {
-  return type === 'file[]' || type === 'files'
+  return typeof type === 'string' && canonicalInputFormatFieldType(type) === 'file[]'
 }
 
 /**

apps/sim/lib/workflows/input-schema.test.ts

@@ -108,9 +108,25 @@ describe('workflow input schemas', () => {
     expect(z.object(generateWorkflowInputShape(fields)).parse(input)).toEqual(input)
   })
 
-  it('rejects unsupported type names instead of advertising strings', () => {
-    expect(() => generateToolInputSchema([{ name: 'files', type: 'unsupported' }])).toThrow(
-      'Unsupported workflow input type "unsupported"'
+  it('accepts the json and files aliases as their canonical types', () => {
+    const shape = z.object(
+      generateWorkflowInputShape([
+        { name: 'payload', type: 'json' },
+        { name: 'documents', type: 'files' },
+      ])
+    )
+    expect(shape.safeParse({ payload: { a: 1 }, documents: [file] }).success).toBe(true)
+    expect(shape.safeParse({ payload: 'text', documents: [file] }).success).toBe(false)
+  })
+
+  it('rejects unsupported type names as a validation failure naming the field', () => {
+    expect(() => generateToolInputSchema([{ name: 'count', type: 'unsupported' }])).toThrow(
+      expect.objectContaining({
+        name: 'OrchestrationError',
+        code: 'validation',
+        message:
+          'Workflow input "count" has unsupported type "unsupported". Use one of: string, number, boolean, object, array, file[].',
+      })
     )
   })
 })

apps/sim/lib/workflows/input-schema.ts

@@ -1,11 +1,16 @@
 import { z } from 'zod'
+import { OrchestrationError } from '@/lib/core/orchestration/types'
 import { workflowFileInputSchema } from '@/lib/workflows/input-file-schema'
+import {
+  canonicalInputFormatFieldType,
+  INPUT_FORMAT_FIELD_TYPES,
+  type InputFormatFieldType,
+} from '@/lib/workflows/input-format-schema'
 import type { InputFormatField } from '@/lib/workflows/types'
 import { isSafeKey } from '@/tools/safe-assign'
 
-function fieldTypeToSchema(type: string | undefined): z.ZodType {
+function fieldTypeToSchema(type: InputFormatFieldType): z.ZodType {
   switch (type) {
-    case undefined:
     case 'string':
       return z.string()
     case 'number':
@@ -16,17 +21,17 @@ function fieldTypeToSchema(type: string | undefined): z.ZodType {
       return z.record(z.string(), z.unknown())
     case 'array':
       return z.array(z.unknown())
-    case 'files':
     case 'file[]':
       return z.array(workflowFileInputSchema)
-    default:
-      throw new Error(`Unsupported workflow input type "${type}"`)
   }
 }
 
 /**
  * Shared by workflow run validation and MCP discovery so the advertised input
  * types match execution. The executor supplies configured defaults at run time.
+ *
+ * @throws OrchestrationError `validation` when a field name is reserved or its
+ * type is not one a workflow input can declare.
  */
 export function generateWorkflowInputShape(inputFormat: InputFormatField[]): z.ZodRawShape {
   const shape: Record<string, z.ZodType> = {}
@@ -35,12 +40,22 @@ export function generateWorkflowInputShape(inputFormat: InputFormatField[]): z.Z
     const name = field.name?.trim()
     if (!name) continue
     if (!isSafeKey(name)) {
-      throw new Error(`Workflow input name "${name}" is reserved. Rename this input field.`)
+      throw new OrchestrationError(
+        'validation',
+        `Workflow input name "${name}" is reserved. Rename this input field.`
+      )
+    }
+    const type = canonicalInputFormatFieldType(field.type)
+    if (!type) {
+      throw new OrchestrationError(
+        'validation',
+        `Workflow input "${name}" has unsupported type "${field.type}". Use one of: ${INPUT_FORMAT_FIELD_TYPES.join(', ')}.`
+      )
     }
 
-    const schema = fieldTypeToSchema(field.type).describe(
+    const schema = fieldTypeToSchema(type).describe(
       field.description?.trim() ||
-        (field.type === 'file[]' || field.type === 'files'
+        (type === 'file[]'
           ? 'Files: use an existing workspace file ID/key, a file upload {type:"file",data:"data:<mime>;base64,...",name}, or URL {type:"url",data:"https://...",name}. Stored metadata and access are rechecked when the workflow runs.'
           : name)
     )

apps/sim/lib/workflows/triggers/run-options.test.ts

@@ -115,6 +115,20 @@ describe('file inputs through workflow run options', () => {
   })
 })
 
+describe('mock payloads for aliased field types', () => {
+  it('samples a json field as an object the run validation accepts', () => {
+    const [option] = resolveTriggerRunOptions({
+      start: {
+        type: 'start_trigger',
+        name: 'Start',
+        subBlocks: { inputFormat: { value: [{ name: 'payload', type: 'json' }] } },
+      },
+    })
+    expect(option.mockPayload).toEqual({ payload: {} })
+    expect(validateTriggerInput(option, option.mockPayload)).toEqual({ ok: true })
+  })
+})
+
 describe('workflow input discovery schemas', () => {
   it('matches optional defaults and describes stored-file and upload alternatives', () => {
     const [option] = resolveTriggerRunOptions({