diff --git a/src/renderer/components/WorkflowEditor.tsx b/src/renderer/components/WorkflowEditor.tsx
index 66835f5..70204bd 100644
--- a/src/renderer/components/WorkflowEditor.tsx
+++ b/src/renderer/components/WorkflowEditor.tsx
@@ -97,10 +97,8 @@ function defaultConfigForKind(kind: WorkflowNodeKind): WorkflowNodeConfig {
         model: 'gpt-5.4',
         reasoningEffort: 'high',
       };
-    case 'code-executor':
-      return { kind: 'code-executor' };
-    case 'function-executor':
-      return { kind: 'function-executor', functionRef: '' };
+    case 'invoke-function':
+      return { kind: 'invoke-function', functionName: '', arguments: {} };
     case 'sub-workflow':
       return { kind: 'sub-workflow' };
     case 'request-port':
@@ -116,10 +114,8 @@ function defaultLabelForKind(kind: WorkflowNodeKind): string {
       return 'End';
     case 'agent':
       return 'New Agent';
-    case 'code-executor':
-      return 'Code Executor';
-    case 'function-executor':
-      return 'Function';
+    case 'invoke-function':
+      return 'Function Tool';
     case 'sub-workflow':
       return 'Sub-Workflow';
     case 'request-port':
diff --git a/src/renderer/components/workflow/CodeExecutorInspector.tsx b/src/renderer/components/workflow/CodeExecutorInspector.tsx
deleted file mode 100644
index cce5065..0000000
--- a/src/renderer/components/workflow/CodeExecutorInspector.tsx
+++ /dev/null
@@ -1,174 +0,0 @@
-import { useCallback } from 'react';
-import { AlertCircle, Code, Trash2 } from 'lucide-react';
-
-import type {
-  CodeExecutorConfig,
-  WorkflowNode,
-  WorkflowNodeConfig,
-  WorkflowValidationIssue,
-} from '@shared/domain/workflow';
-
-interface CodeExecutorInspectorProps {
-  node: WorkflowNode;
-  validationIssues?: WorkflowValidationIssue[];
-  onNodeChange: (nodeId: string, patch: Partial<WorkflowNode>) => void;
-  onNodeConfigChange: (nodeId: string, config: WorkflowNodeConfig) => void;
-  onNodeRemove: (nodeId: string) => void;
-}
-
-function InputField({
-  label,
-  value,
-  onChange,
-  multiline,
-  placeholder,
-}: {
-  label: string;
-  value: string;
-  onChange: (value: string) => void;
-  multiline?: boolean;
-  placeholder?: string;
-}) {
-  const base =
-    'w-full rounded-lg border border-[var(--color-border)] bg-[var(--color-surface-1)] px-3 py-2 text-[13px] text-[var(--color-text-primary)] placeholder-[var(--color-text-muted)] outline-none transition focus:border-[var(--color-accent)]/50';
-  return (
-    <label className="block space-y-1.5">
-      <span className="text-[12px] font-medium text-[var(--color-text-secondary)]">{label}</span>
-      {multiline ? (
-        <textarea
-          className={`${base} min-h-20 resize-y`}
-          onChange={(e) => onChange(e.target.value)}
-          placeholder={placeholder}
-          value={value}
-        />
-      ) : (
-        <input
-          className={base}
-          onChange={(e) => onChange(e.target.value)}
-          placeholder={placeholder}
-          value={value}
-        />
-      )}
-    </label>
-  );
-}
-
-export function CodeExecutorInspector({
-  node,
-  validationIssues,
-  onNodeChange,
-  onNodeConfigChange,
-  onNodeRemove,
-}: CodeExecutorInspectorProps) {
-  const config = node.config as CodeExecutorConfig;
-  const nodeIssues = validationIssues?.filter((i) => i.nodeId === node.id) ?? [];
-
-  const patchConfig = useCallback(
-    (patch: Partial<CodeExecutorConfig>) => {
-      onNodeConfigChange(node.id, { ...config, ...patch });
-    },
-    [node.id, config, onNodeConfigChange],
-  );
-
-  return (
-    <div className="space-y-4">
-      {/* Header */}
-      <div className="flex items-center justify-between">
-        <div className="flex items-center gap-2.5">
-          <div className="flex size-8 items-center justify-center rounded-lg bg-sky-500/10">
-            <Code className="size-4 text-sky-400" />
-          </div>
-          <div className="text-[13px] font-semibold text-[var(--color-text-primary)]">
-            {node.label || 'Code Executor'}
-          </div>
-        </div>
-        <button
-          className="flex size-7 items-center justify-center rounded-lg text-[var(--color-text-muted)] transition-all duration-200 hover:bg-[var(--color-status-error)]/10 hover:text-[var(--color-status-error)]"
-          onClick={() => onNodeRemove(node.id)}
-          title="Remove node"
-          type="button"
-        >
-          <Trash2 className="size-3.5" />
-        </button>
-      </div>
-
-      {/* Label */}
-      <InputField
-        label="Label"
-        onChange={(v) => onNodeChange(node.id, { label: v })}
-        placeholder="Display label"
-        value={node.label}
-      />
-
-      {/* Implementation */}
-      <label className="block space-y-1.5">
-        <span className="text-[12px] font-medium text-[var(--color-text-secondary)]">
-          Implementation
-        </span>
-        <textarea
-          className="w-full rounded-lg border border-[var(--color-border)] bg-[var(--color-surface-1)] px-3 py-2 font-mono text-[13px] text-[var(--color-text-primary)] placeholder-[var(--color-text-muted)] outline-none transition focus:border-[var(--color-accent)]/50 min-h-20 resize-y"
-          onChange={(e) => patchConfig({ implementation: e.target.value })}
-          placeholder="e.g. return-input, return-text:hello, state:set:scope:key:{&quot;value&quot;:1}"
-          value={config.implementation ?? ''}
-        />
-      </label>
-
-      {/* Directives help */}
-      <div className="rounded-lg border border-sky-500/20 bg-sky-500/5 px-3 py-2 text-[12px] text-sky-400">
-        <div className="mb-1.5 font-medium">Supported directives</div>
-        <ul className="space-y-0.5 text-[11px]">
-          <li>
-            <code className="font-mono">return-input</code> — Forward incoming payload
-          </li>
-          <li>
-            <code className="font-mono">return-text:&lt;text&gt;</code> — Emit literal text
-          </li>
-          <li>
-            <code className="font-mono">return-json:&lt;json&gt;</code> — Emit parsed JSON
-          </li>
-          <li>
-            <code className="font-mono">state:set:&lt;scope&gt;:&lt;key&gt;:&lt;json&gt;</code> — Set state value
-          </li>
-          <li>
-            <code className="font-mono">state:get:&lt;scope&gt;:&lt;key&gt;</code> — Read state value
-          </li>
-        </ul>
-      </div>
-
-      {/* Input Type */}
-      <InputField
-        label="Input Type"
-        onChange={(v) => patchConfig({ inputType: v || undefined })}
-        placeholder="Optional type annotation"
-        value={config.inputType ?? ''}
-      />
-
-      {/* Output Type */}
-      <InputField
-        label="Output Type"
-        onChange={(v) => patchConfig({ outputType: v || undefined })}
-        placeholder="Optional type annotation"
-        value={config.outputType ?? ''}
-      />
-
-      {/* Validation issues */}
-      {nodeIssues.length > 0 && (
-        <div className="space-y-1">
-          {nodeIssues.map((issue, i) => (
-            <div
-              className={`flex items-start gap-1.5 rounded-lg px-2.5 py-1.5 text-[11px] ${
-                issue.level === 'error'
-                  ? 'bg-[var(--color-status-error)]/10 text-[var(--color-status-error)]'
-                  : 'bg-[var(--color-status-warning)]/10 text-[var(--color-status-warning)]'
-              }`}
-              key={`${issue.field ?? 'v'}-${i}`}
-            >
-              <AlertCircle className="mt-0.5 size-3 shrink-0" />
-              <span>{issue.message}</span>
-            </div>
-          ))}
-        </div>
-      )}
-    </div>
-  );
-}
diff --git a/src/renderer/components/workflow/FunctionExecutorInspector.tsx b/src/renderer/components/workflow/InvokeFunctionInspector.tsx
similarity index 67%
rename from src/renderer/components/workflow/FunctionExecutorInspector.tsx
rename to src/renderer/components/workflow/InvokeFunctionInspector.tsx
index 2c6e186..2fee2f0 100644
--- a/src/renderer/components/workflow/FunctionExecutorInspector.tsx
+++ b/src/renderer/components/workflow/InvokeFunctionInspector.tsx
@@ -2,13 +2,13 @@ import { useCallback, useState } from 'react';
 import { AlertCircle, FunctionSquare, Plus, Trash2, X } from 'lucide-react';
 
 import type {
-  FunctionExecutorConfig,
+  InvokeFunctionConfig,
   WorkflowNode,
   WorkflowNodeConfig,
   WorkflowValidationIssue,
 } from '@shared/domain/workflow';
 
-interface FunctionExecutorInspectorProps {
+interface InvokeFunctionInspectorProps {
   node: WorkflowNode;
   validationIssues?: WorkflowValidationIssue[];
   onNodeChange: (nodeId: string, patch: Partial<WorkflowNode>) => void;
@@ -42,66 +42,58 @@ function InputField({
   );
 }
 
-const builtInFunctions = [
-  { value: 'identity', label: 'identity — Pass through input' },
-  { value: 'return-parameter', label: 'return-parameter — Return a parameter value' },
-  { value: 'concat-text', label: 'concat-text — Concatenate text values' },
-  { value: 'state:get', label: 'state:get — Read state value' },
-  { value: 'state:set', label: 'state:set — Set state value' },
-] as const;
-
 function stringifyValue(v: unknown): string {
   if (typeof v === 'string') return v;
   return JSON.stringify(v) ?? '';
 }
 
-export function FunctionExecutorInspector({
+export function InvokeFunctionInspector({
   node,
   validationIssues,
   onNodeChange,
   onNodeConfigChange,
   onNodeRemove,
-}: FunctionExecutorInspectorProps) {
-  const config = node.config as FunctionExecutorConfig;
+}: InvokeFunctionInspectorProps) {
+  const config = node.config as InvokeFunctionConfig;
   const nodeIssues = validationIssues?.filter((i) => i.nodeId === node.id) ?? [];
-  const parameters = config.parameters ?? {};
-  const paramEntries = Object.entries(parameters);
+  const args = config.arguments ?? {};
+  const argEntries = Object.entries(args);
 
   const [newKey, setNewKey] = useState('');
 
   const patchConfig = useCallback(
-    (patch: Partial<FunctionExecutorConfig>) => {
+    (patch: Partial<InvokeFunctionConfig>) => {
       onNodeConfigChange(node.id, { ...config, ...patch });
     },
     [node.id, config, onNodeConfigChange],
   );
 
-  const handleParamChange = useCallback(
-    (oldKey: string, newParamKey: string, value: string) => {
-      const next = { ...parameters };
-      if (newParamKey !== oldKey) {
+  const handleArgChange = useCallback(
+    (oldKey: string, newArgKey: string, value: string) => {
+      const next = { ...args };
+      if (newArgKey !== oldKey) {
         delete next[oldKey];
       }
-      next[newParamKey] = value;
-      patchConfig({ parameters: next });
+      next[newArgKey] = value;
+      patchConfig({ arguments: next });
     },
-    [parameters, patchConfig],
+    [args, patchConfig],
   );
 
-  const handleParamRemove = useCallback(
+  const handleArgRemove = useCallback(
     (key: string) => {
-      const next = { ...parameters };
+      const next = { ...args };
       delete next[key];
-      patchConfig({ parameters: next });
+      patchConfig({ arguments: next });
     },
-    [parameters, patchConfig],
+    [args, patchConfig],
   );
 
-  const handleParamAdd = useCallback(() => {
-    const key = newKey.trim() || `param${paramEntries.length + 1}`;
-    patchConfig({ parameters: { ...parameters, [key]: '' } });
+  const handleArgAdd = useCallback(() => {
+    const key = newKey.trim() || `arg${argEntries.length + 1}`;
+    patchConfig({ arguments: { ...args, [key]: '' } });
     setNewKey('');
-  }, [newKey, paramEntries.length, parameters, patchConfig]);
+  }, [newKey, argEntries.length, args, patchConfig]);
 
   return (
     <div className="space-y-4">
@@ -112,7 +104,7 @@ export function FunctionExecutorInspector({
             <FunctionSquare className="size-4 text-violet-400" />
           </div>
           <div className="text-[13px] font-semibold text-[var(--color-text-primary)]">
-            {node.label || 'Function Executor'}
+            {node.label || 'Function Tool'}
           </div>
         </div>
         <button
@@ -133,61 +125,73 @@ export function FunctionExecutorInspector({
         value={node.label}
       />
 
-      {/* Function reference */}
-      <label className="block space-y-1.5">
-        <span className="text-[12px] font-medium text-[var(--color-text-secondary)]">Function</span>
-        <select
-          className="w-full rounded-lg border border-[var(--color-border)] bg-[var(--color-surface-1)] px-3 py-2 text-[13px] text-[var(--color-text-primary)] outline-none transition focus:border-[var(--color-accent)]/50"
-          onChange={(e) => patchConfig({ functionRef: e.target.value })}
-          value={config.functionRef}
-        >
-          <option value="">Select a function…</option>
-          {builtInFunctions.map((fn) => (
-            <option key={fn.value} value={fn.value}>
-              {fn.label}
-            </option>
-          ))}
-        </select>
+      {/* Function name */}
+      <InputField
+        label="Function Name"
+        onChange={(v) => patchConfig({ functionName: v })}
+        placeholder="e.g. GetUserData"
+        value={config.functionName}
+      />
+
+      {/* Result variable */}
+      <InputField
+        label="Result Variable"
+        onChange={(v) => patchConfig({ resultVariable: v || undefined })}
+        placeholder="e.g. Local.result"
+        value={config.resultVariable ?? ''}
+      />
+
+      {/* Require approval */}
+      <label className="flex items-center justify-between">
+        <span className="text-[12px] font-medium text-[var(--color-text-secondary)]">
+          Require Approval
+        </span>
+        <input
+          checked={config.requireApproval === true}
+          className="size-4 accent-[var(--color-accent)]"
+          onChange={(e) => patchConfig({ requireApproval: e.target.checked || undefined })}
+          type="checkbox"
+        />
       </label>
 
-      {/* Parameters editor */}
+      {/* Arguments editor */}
       <div className="space-y-1.5">
         <div className="flex items-center justify-between">
           <span className="text-[12px] font-medium text-[var(--color-text-secondary)]">
-            Parameters
+            Arguments
           </span>
           <button
             className="flex size-6 items-center justify-center rounded-md text-[var(--color-text-muted)] transition-all duration-200 hover:bg-[var(--color-accent)]/10 hover:text-[var(--color-accent)]"
-            onClick={handleParamAdd}
-            title="Add parameter"
+            onClick={handleArgAdd}
+            title="Add argument"
             type="button"
           >
             <Plus className="size-3.5" />
           </button>
         </div>
 
-        {paramEntries.length === 0 && (
-          <p className="text-[11px] text-[var(--color-text-muted)]">No parameters defined.</p>
+        {argEntries.length === 0 && (
+          <p className="text-[11px] text-[var(--color-text-muted)]">No arguments defined.</p>
         )}
 
-        {paramEntries.map(([key, value]) => (
+        {argEntries.map(([key, value]) => (
           <div className="flex items-center gap-1.5" key={key}>
             <input
               className="w-1/3 rounded-lg border border-[var(--color-border)] bg-[var(--color-surface-1)] px-2 py-1.5 text-[12px] text-[var(--color-text-primary)] placeholder-[var(--color-text-muted)] outline-none transition focus:border-[var(--color-accent)]/50"
-              onChange={(e) => handleParamChange(key, e.target.value, stringifyValue(value))}
+              onChange={(e) => handleArgChange(key, e.target.value, stringifyValue(value))}
               placeholder="key"
               value={key}
             />
             <input
               className="flex-1 rounded-lg border border-[var(--color-border)] bg-[var(--color-surface-1)] px-2 py-1.5 text-[12px] text-[var(--color-text-primary)] placeholder-[var(--color-text-muted)] outline-none transition focus:border-[var(--color-accent)]/50"
-              onChange={(e) => handleParamChange(key, key, e.target.value)}
+              onChange={(e) => handleArgChange(key, key, e.target.value)}
               placeholder="value"
               value={stringifyValue(value)}
             />
             <button
               className="flex size-6 shrink-0 items-center justify-center rounded-md text-[var(--color-text-muted)] transition-all duration-200 hover:bg-[var(--color-status-error)]/10 hover:text-[var(--color-status-error)]"
-              onClick={() => handleParamRemove(key)}
-              title="Remove parameter"
+              onClick={() => handleArgRemove(key)}
+              title="Remove argument"
               type="button"
             >
               <X className="size-3" />
diff --git a/src/renderer/components/workflow/WorkflowGraphInspector.tsx b/src/renderer/components/workflow/WorkflowGraphInspector.tsx
index c8b3f87..5b2b5d2 100644
--- a/src/renderer/components/workflow/WorkflowGraphInspector.tsx
+++ b/src/renderer/components/workflow/WorkflowGraphInspector.tsx
@@ -1,5 +1,5 @@
 import { useCallback } from 'react';
-import { AlertCircle, Bot, Code, FunctionSquare, GitBranch, Info, Radio, Trash2 } from 'lucide-react';
+import { AlertCircle, Bot, FunctionSquare, GitBranch, Info, Radio, Trash2 } from 'lucide-react';
 
 import {
   findModel,
@@ -17,9 +17,8 @@ import type {
   AgentNodeConfig,
 } from '@shared/domain/workflow';
 import { ModelSelect, ReasoningEffortSelect } from '@renderer/components/AgentConfigFields';
-import { CodeExecutorInspector } from '@renderer/components/workflow/CodeExecutorInspector';
+import { InvokeFunctionInspector } from '@renderer/components/workflow/InvokeFunctionInspector';
 import { ConditionEditor } from '@renderer/components/workflow/ConditionEditor';
-import { FunctionExecutorInspector } from '@renderer/components/workflow/FunctionExecutorInspector';
 import { RequestPortInspector } from '@renderer/components/workflow/RequestPortInspector';
 import { SubWorkflowInspector } from '@renderer/components/workflow/SubWorkflowInspector';
 
@@ -194,9 +193,7 @@ function SystemNodeInspector({ node }: { node: WorkflowNode }) {
 
 /* ── Placeholder inspector for future node kinds ───────────── */
 
-const placeholderIcons: Record<string, typeof Code> = {
-  'code-executor': Code,
-  'function-executor': FunctionSquare,
+const placeholderIcons: Record<string, typeof FunctionSquare> = {
   'sub-workflow': GitBranch,
   'request-port': Radio,
 };
@@ -460,24 +457,10 @@ export function WorkflowGraphInspector({
     );
   }
 
-  if (selectedNode.kind === 'code-executor') {
+  if (selectedNode.kind === 'invoke-function') {
     return (
       <div className="p-4">
-        <CodeExecutorInspector
-          node={selectedNode}
-          validationIssues={validationIssues}
-          onNodeChange={onNodeChange}
-          onNodeConfigChange={onNodeConfigChange}
-          onNodeRemove={onNodeRemove}
-        />
-      </div>
-    );
-  }
-
-  if (selectedNode.kind === 'function-executor') {
-    return (
-      <div className="p-4">
-        <FunctionExecutorInspector
+        <InvokeFunctionInspector
           node={selectedNode}
           validationIssues={validationIssues}
           onNodeChange={onNodeChange}
diff --git a/src/renderer/components/workflow/WorkflowGraphNodes.tsx b/src/renderer/components/workflow/WorkflowGraphNodes.tsx
index 8e8efcb..d920c19 100644
--- a/src/renderer/components/workflow/WorkflowGraphNodes.tsx
+++ b/src/renderer/components/workflow/WorkflowGraphNodes.tsx
@@ -1,6 +1,6 @@
 import { memo } from 'react';
 import { Handle, Position, type NodeProps } from '@xyflow/react';
-import { Bot, Circle, Code, FunctionSquare, GitBranch, Link2, Radio, Play, Square } from 'lucide-react';
+import { Bot, Circle, FunctionSquare, GitBranch, Link2, Radio, Play, Square } from 'lucide-react';
 
 import type { WorkflowGraphNodeData } from '@renderer/lib/workflowGraph';
 import type { WorkflowNodeKind } from '@shared/domain/workflow';
@@ -12,8 +12,7 @@ const kindColors: Record<WorkflowNodeKind, { bg: string; border: string; text: s
   start: { bg: 'bg-emerald-500/10', border: 'border-emerald-500/30', text: 'text-emerald-400' },
   end: { bg: 'bg-rose-500/10', border: 'border-rose-500/30', text: 'text-rose-400' },
   agent: { bg: 'bg-[var(--color-surface-2)]/80', border: 'border-[var(--color-border)]/40', text: 'text-[var(--color-text-primary)]' },
-  'code-executor': { bg: 'bg-sky-500/10', border: 'border-sky-500/30', text: 'text-sky-400' },
-  'function-executor': { bg: 'bg-violet-500/10', border: 'border-violet-500/30', text: 'text-violet-400' },
+  'invoke-function': { bg: 'bg-violet-500/10', border: 'border-violet-500/30', text: 'text-violet-400' },
   'sub-workflow': { bg: 'bg-amber-500/10', border: 'border-amber-500/30', text: 'text-amber-400' },
   'request-port': { bg: 'bg-teal-500/10', border: 'border-teal-500/30', text: 'text-teal-400' },
 };
@@ -22,8 +21,7 @@ const kindIcons: Record<WorkflowNodeKind, typeof Bot> = {
   start: Play,
   end: Square,
   agent: Bot,
-  'code-executor': Code,
-  'function-executor': FunctionSquare,
+  'invoke-function': FunctionSquare,
   'sub-workflow': GitBranch,
   'request-port': Radio,
 };
@@ -115,18 +113,7 @@ export const AgentNode = memo(function AgentNode({ data, selected }: NodeProps)
   );
 });
 
-export const CodeExecutorNode = memo(function CodeExecutorNode({ data, selected }: NodeProps) {
-  const nodeData = data as unknown as WorkflowGraphNodeData;
-  return (
-    <>
-      <Handle type="target" position={Position.Left} className={handleStyles.flow} />
-      <WorkflowNodeContent data={nodeData} selected={selected ?? false} />
-      <Handle type="source" position={Position.Right} className={handleStyles.flow} />
-    </>
-  );
-});
-
-export const FunctionExecutorNode = memo(function FunctionExecutorNode({ data, selected }: NodeProps) {
+export const InvokeFunctionNode = memo(function InvokeFunctionNode({ data, selected }: NodeProps) {
   const nodeData = data as unknown as WorkflowGraphNodeData;
   return (
     <>
@@ -165,8 +152,7 @@ export const workflowNodeTypes = {
   startNode: StartNode,
   endNode: EndNode,
   agentNode: AgentNode,
-  codeExecutorNode: CodeExecutorNode,
-  functionExecutorNode: FunctionExecutorNode,
+  invokeFunctionNode: InvokeFunctionNode,
   subWorkflowNode: SubWorkflowNode,
   requestPortNode: RequestPortNode,
 };
diff --git a/src/renderer/components/workflow/WorkflowNodePalette.tsx b/src/renderer/components/workflow/WorkflowNodePalette.tsx
index 6788bde..211d987 100644
--- a/src/renderer/components/workflow/WorkflowNodePalette.tsx
+++ b/src/renderer/components/workflow/WorkflowNodePalette.tsx
@@ -1,4 +1,4 @@
-import { Bot, Code, FunctionSquare, GitBranch, Play, Radio, Square } from 'lucide-react';
+import { Bot, FunctionSquare, GitBranch, Play, Radio, Square } from 'lucide-react';
 
 import type { WorkflowNodeKind } from '@shared/domain/workflow';
 
@@ -36,8 +36,7 @@ const paletteGroups: PaletteGroup[] = [
   {
     label: 'Processing',
     items: [
-      { kind: 'code-executor', label: 'Code', icon: Code, color: 'text-sky-400' },
-      { kind: 'function-executor', label: 'Function', icon: FunctionSquare, color: 'text-violet-400' },
+      { kind: 'invoke-function', label: 'Function Tool', icon: FunctionSquare, color: 'text-violet-400' },
     ],
   },
   {
diff --git a/src/renderer/lib/workflowGraph.ts b/src/renderer/lib/workflowGraph.ts
index d81102d..57111ce 100644
--- a/src/renderer/lib/workflowGraph.ts
+++ b/src/renderer/lib/workflowGraph.ts
@@ -36,10 +36,8 @@ function resolveNodeType(kind: WorkflowNodeKind): string {
       return 'endNode';
     case 'agent':
       return 'agentNode';
-    case 'code-executor':
-      return 'codeExecutorNode';
-    case 'function-executor':
-      return 'functionExecutorNode';
+    case 'invoke-function':
+      return 'invokeFunctionNode';
     case 'sub-workflow':
       return 'subWorkflowNode';
     case 'request-port':
diff --git a/src/shared/domain/workflow.ts b/src/shared/domain/workflow.ts
index ddb39f7..695d28d 100644
--- a/src/shared/domain/workflow.ts
+++ b/src/shared/domain/workflow.ts
@@ -10,8 +10,7 @@ export type WorkflowNodeKind =
   | 'start'
   | 'end'
   | 'agent'
-  | 'code-executor'
-  | 'function-executor'
+  | 'invoke-function'
   | 'sub-workflow'
   | 'request-port';
 
@@ -61,17 +60,12 @@ export interface AgentNodeConfig extends PatternAgentDefinition {
   kind: 'agent';
 }
 
-export interface CodeExecutorConfig {
-  kind: 'code-executor';
-  inputType?: string;
-  outputType?: string;
-  implementation?: string;
-}
-
-export interface FunctionExecutorConfig {
-  kind: 'function-executor';
-  functionRef: string;
-  parameters?: Record<string, unknown>;
+export interface InvokeFunctionConfig {
+  kind: 'invoke-function';
+  functionName: string;
+  arguments?: Record<string, unknown>;
+  requireApproval?: boolean;
+  resultVariable?: string;
 }
 
 export interface SubWorkflowConfig {
@@ -92,8 +86,7 @@ export type WorkflowNodeConfig =
   | StartNodeConfig
   | EndNodeConfig
   | AgentNodeConfig
-  | CodeExecutorConfig
-  | FunctionExecutorConfig
+  | InvokeFunctionConfig
   | SubWorkflowConfig
   | RequestPortConfig;
 
@@ -174,8 +167,7 @@ const executableNodeKinds = new Set<WorkflowNodeKind>([
   'start',
   'end',
   'agent',
-  'code-executor',
-  'function-executor',
+  'invoke-function',
   'sub-workflow',
   'request-port',
 ]);
@@ -219,21 +211,14 @@ function normalizeNodeConfig(kind: WorkflowNodeKind, config?: Partial<WorkflowNo
         overrides: agent?.overrides,
       };
     }
-    case 'code-executor': {
-      const value = config as Partial<CodeExecutorConfig> | undefined;
+    case 'invoke-function': {
+      const value = config as Partial<InvokeFunctionConfig> | undefined;
       return {
         kind,
-        inputType: normalizeOptionalString(value?.inputType),
-        outputType: normalizeOptionalString(value?.outputType),
-        implementation: value?.implementation?.trim(),
-      };
-    }
-    case 'function-executor': {
-      const value = config as Partial<FunctionExecutorConfig> | undefined;
-      return {
-        kind,
-        functionRef: normalizeOptionalString(value?.functionRef) ?? '',
-        parameters: value?.parameters,
+        functionName: normalizeOptionalString(value?.functionName) ?? '',
+        arguments: value?.arguments,
+        requireApproval: value?.requireApproval,
+        resultVariable: normalizeOptionalString(value?.resultVariable),
       };
     }
     case 'sub-workflow': {
@@ -750,23 +735,13 @@ function validateSubWorkflowNode(node: WorkflowNode, issues: WorkflowValidationI
 
 function validateExecutableNodeConfig(node: WorkflowNode, issues: WorkflowValidationIssue[]): void {
   switch (node.kind) {
-    case 'code-executor':
-      if (node.config.kind === 'code-executor' && !node.config.implementation?.trim()) {
+    case 'invoke-function':
+      if (node.config.kind === 'invoke-function' && !node.config.functionName.trim()) {
         addIssue(issues, {
           level: 'error',
-          field: 'graph.nodes.config.implementation',
+          field: 'graph.nodes.config.functionName',
           nodeId: node.id,
-          message: 'Code executor nodes require a non-empty implementation.',
-        });
-      }
-      return;
-    case 'function-executor':
-      if (node.config.kind === 'function-executor' && !node.config.functionRef.trim()) {
-        addIssue(issues, {
-          level: 'error',
-          field: 'graph.nodes.config.functionRef',
-          nodeId: node.id,
-          message: 'Function executor nodes require a non-empty functionRef.',
+          message: 'Function tool nodes require a non-empty functionName.',
         });
       }
       return;
@@ -930,8 +905,7 @@ export function validateWorkflowDefinition(workflow: WorkflowDefinition): Workfl
   const endNodes = normalized.graph.nodes.filter((node) => node.kind === 'end');
   const executableWorkNodes = normalized.graph.nodes.filter((node) =>
     node.kind === 'agent'
-    || node.kind === 'code-executor'
-    || node.kind === 'function-executor'
+    || node.kind === 'invoke-function'
     || node.kind === 'sub-workflow'
     || node.kind === 'request-port');
 
diff --git a/tests/shared/workflow.test.ts b/tests/shared/workflow.test.ts
index 883624d..89806dc 100644
--- a/tests/shared/workflow.test.ts
+++ b/tests/shared/workflow.test.ts
@@ -119,17 +119,17 @@ describe('workflow validation', () => {
   test('accepts phase 4 executor node kinds as executable work', () => {
     const workflow = createWorkflow();
     workflow.graph.nodes[1] = {
-      id: 'code-executor',
-      kind: 'code-executor',
-      label: 'Transform',
+      id: 'invoke-function',
+      kind: 'invoke-function',
+      label: 'Function Tool',
       position: { x: 100, y: 0 },
       config: {
-        kind: 'code-executor',
-        implementation: 'return-text:done',
+        kind: 'invoke-function',
+        functionName: 'GetUserData',
       },
     };
-    workflow.graph.edges[0] = { id: 'edge-start-code', source: 'start', target: 'code-executor', kind: 'direct' };
-    workflow.graph.edges[1] = { id: 'edge-code-end', source: 'code-executor', target: 'end', kind: 'direct' };
+    workflow.graph.edges[0] = { id: 'edge-start-fn', source: 'start', target: 'invoke-function', kind: 'direct' };
+    workflow.graph.edges[1] = { id: 'edge-fn-end', source: 'invoke-function', target: 'end', kind: 'direct' };
 
     expect(validateWorkflowDefinition(workflow)).toEqual([]);
   });
@@ -137,17 +137,17 @@ describe('workflow validation', () => {
   test('counts function and request port nodes as executable work', () => {
     const functionWorkflow = createWorkflow();
     functionWorkflow.graph.nodes[1] = {
-      id: 'function-executor',
-      kind: 'function-executor',
-      label: 'Function',
+      id: 'invoke-function',
+      kind: 'invoke-function',
+      label: 'Function Tool',
       position: { x: 200, y: 0 },
       config: {
-        kind: 'function-executor',
-        functionRef: 'identity',
+        kind: 'invoke-function',
+        functionName: 'identity',
       },
     };
-    functionWorkflow.graph.edges[0] = { id: 'edge-start-function', source: 'start', target: 'function-executor', kind: 'direct' };
-    functionWorkflow.graph.edges[1] = { id: 'edge-function-end', source: 'function-executor', target: 'end', kind: 'direct' };
+    functionWorkflow.graph.edges[0] = { id: 'edge-start-function', source: 'start', target: 'invoke-function', kind: 'direct' };
+    functionWorkflow.graph.edges[1] = { id: 'edge-function-end', source: 'invoke-function', target: 'end', kind: 'direct' };
 
     const requestPortWorkflow = createWorkflow();
     requestPortWorkflow.graph.nodes[1] = {
@@ -170,33 +170,19 @@ describe('workflow validation', () => {
   });
 
   test('rejects invalid phase 4 executor configs', () => {
-    const codeWorkflow = createWorkflow();
-    codeWorkflow.graph.nodes[1] = {
-      id: 'code-executor',
-      kind: 'code-executor',
-      label: 'Code',
-      position: { x: 200, y: 0 },
-      config: {
-        kind: 'code-executor',
-        implementation: '   ',
-      },
-    };
-    codeWorkflow.graph.edges[0] = { id: 'edge-start-code', source: 'start', target: 'code-executor', kind: 'direct' };
-    codeWorkflow.graph.edges[1] = { id: 'edge-code-end', source: 'code-executor', target: 'end', kind: 'direct' };
-
     const functionWorkflow = createWorkflow();
     functionWorkflow.graph.nodes[1] = {
-      id: 'function-executor',
-      kind: 'function-executor',
-      label: 'Function',
+      id: 'invoke-function',
+      kind: 'invoke-function',
+      label: 'Function Tool',
       position: { x: 200, y: 0 },
       config: {
-        kind: 'function-executor',
-        functionRef: '   ',
+        kind: 'invoke-function',
+        functionName: '   ',
       },
     };
-    functionWorkflow.graph.edges[0] = { id: 'edge-start-function', source: 'start', target: 'function-executor', kind: 'direct' };
-    functionWorkflow.graph.edges[1] = { id: 'edge-function-end', source: 'function-executor', target: 'end', kind: 'direct' };
+    functionWorkflow.graph.edges[0] = { id: 'edge-start-function', source: 'start', target: 'invoke-function', kind: 'direct' };
+    functionWorkflow.graph.edges[1] = { id: 'edge-function-end', source: 'invoke-function', target: 'end', kind: 'direct' };
 
     const requestPortWorkflow = createWorkflow();
     requestPortWorkflow.graph.nodes[1] = {
@@ -214,8 +200,7 @@ describe('workflow validation', () => {
     requestPortWorkflow.graph.edges[0] = { id: 'edge-start-port', source: 'start', target: 'request-port', kind: 'direct' };
     requestPortWorkflow.graph.edges[1] = { id: 'edge-port-end', source: 'request-port', target: 'end', kind: 'direct' };
 
-    expect(validateWorkflowDefinition(codeWorkflow).some((issue) => issue.field === 'graph.nodes.config.implementation')).toBe(true);
-    expect(validateWorkflowDefinition(functionWorkflow).some((issue) => issue.field === 'graph.nodes.config.functionRef')).toBe(true);
+    expect(validateWorkflowDefinition(functionWorkflow).some((issue) => issue.field === 'graph.nodes.config.functionName')).toBe(true);
 
     const requestPortIssues = validateWorkflowDefinition(requestPortWorkflow);
     expect(requestPortIssues.some((issue) => issue.field === 'graph.nodes.config.portId')).toBe(true);