feat(ai-studio): add agent-harness node for external coding-agent delegation

.changeset/temporal-node-activity-heartbeat-timeout.md

@@ -0,0 +1,5 @@
+---
+'@workflowbuilder/temporal': minor
+---
+
+`ActivityProfile` (and `nodeActivityProfiles`) gains an optional `heartbeatTimeout` key for long-running activities that need Temporal to detect a stalled or crashed worker faster than `startToCloseTimeout` alone allows.

apps/ai-studio/README.md

@@ -24,3 +24,30 @@ This is a sibling to `apps/demo`, not a layer over it. They share the SDK; nothi
 | Backend      | None (pure SPA)             | Required (Hono + Temporal)                               |
 | Plugin model | Plugins decorate the editor | Direct JSX composition; one slim plugin for node markers |
 | Dev port     | 4200                        | 4201                                                     |
+
+## Agent Harness node
+
+`Agent Harness` (`ai-studio/agent-harness`) delegates a workflow step to an external
+autonomous coding-agent CLI (GitHub Copilot in v1) instead of a single bounded LLM call.
+Its property panel has four accordion sections: **General** (label, prompt, provider),
+**Execution** (model, effort, context, idle timeout), **Tools** (tools preset,
+allowed/denied tool lists), and **Advanced** (output format, MCP config, skills,
+sub-agents, max budget, mutates-checkout, persist-session).
+
+**Functional in v1:** `prompt`, `provider` (`copilot` only), `model`, `effort`,
+`idle_timeout`, `mutatesCheckout`, `agents`.
+
+**Rendered but NOT YET SUPPORTED in v1** (backend deferred, but per issue #147's "fields
+must still render" requirement they are intentionally present rather than hidden —
+this is not an oversight): `context` beyond `'fresh'` (`'shared'`/`'resume'` need session
+persistence), `output_format` (no structured-output enforcement yet), `mcp`, `skills`,
+`maxBudgetUsd`, `persistSession`. Each of these fields' label/placeholder in the panel
+says "not yet supported" so this is visible in the UI itself, not just in this doc.
+
+**`idle_timeout` is in milliseconds, not seconds.** `300` means 300ms; for a 5-minute
+timeout set `idle_timeout: 300000`.
+
+**Demo template:** "Agent Harness Demo" (`data/agent-harness-flow.ts`) — a
+`trigger` → `agent-harness` → `visualize` chain that asks the agent to write a
+`plan.md` outlining rate-limiting approaches and summarize the tradeoffs, exercising
+both file tools and a returned text result.

apps/ai-studio/src/data/agent-harness-flow.ts

@@ -0,0 +1,100 @@
+import type { DiagramModel, TemplateModel } from '@workflowbuilder/sdk';
+
+const diagram: DiagramModel = {
+  name: 'Agent Harness Demo',
+  diagram: {
+    nodes: [
+      {
+        id: 'trigger-1',
+        type: 'start-node',
+        position: { x: 0, y: 300 },
+        data: {
+          segments: [],
+          isStartNode: true,
+          properties: {
+            label: 'Start',
+            description: 'Kicks off the agent harness demo.',
+            inputPrompt: `Create a file plan.md outlining three approaches to rate-limiting an HTTP API, then summarize the tradeoffs.`,
+          },
+          type: 'ai-studio/trigger',
+          icon: 'Lightning',
+        },
+        selected: false,
+        measured: { width: 258, height: 63 },
+        dragging: false,
+      },
+      {
+        id: 'agent-harness-1',
+        type: 'node',
+        position: { x: 380, y: 300 },
+        data: {
+          segments: [],
+          properties: {
+            label: 'Agent Harness',
+            description: 'Delegates the task to Copilot via the agent harness CLI.',
+            prompt: `Create a file plan.md outlining three approaches to rate-limiting an HTTP API, then summarize the tradeoffs.`,
+            provider: 'copilot',
+            model: 'auto',
+            context: 'fresh',
+            toolsMode: 'all',
+            mutatesCheckout: false,
+            persistSession: false,
+            idle_timeout: 300_000,
+          },
+          type: 'ai-studio/agent-harness',
+          icon: 'Terminal',
+        },
+        selected: false,
+        measured: { width: 258, height: 123 },
+        dragging: false,
+      },
+      {
+        id: 'visualize-1',
+        type: 'node',
+        position: { x: 760, y: 300 },
+        data: {
+          segments: [],
+          properties: {
+            label: 'Visualize',
+            description: 'Renders the agent output (auto-detects the format).',
+            mode: 'auto',
+          },
+          type: 'ai-studio/visualize',
+          icon: 'Eye',
+        },
+        selected: false,
+        measured: { width: 258, height: 123 },
+        dragging: false,
+      },
+    ],
+    edges: [
+      {
+        source: 'trigger-1',
+        sourceHandle: 'source',
+        target: 'agent-harness-1',
+        targetHandle: 'target',
+        type: 'labelEdge',
+        id: 'edge-trigger-agent-harness',
+        data: {},
+      },
+      {
+        source: 'agent-harness-1',
+        sourceHandle: 'source',
+        target: 'visualize-1',
+        targetHandle: 'target',
+        type: 'labelEdge',
+        id: 'edge-agent-harness-visualize',
+        data: {},
+      },
+    ],
+    viewport: { x: 180, y: 150, zoom: 0.7 },
+  },
+  layoutDirection: 'RIGHT',
+};
+
+export const agentHarnessFlow: TemplateModel = {
+  id: 306,
+  name: 'Agent Harness Demo',
+  value: diagram,
+  icon: 'Terminal',
+};

apps/ai-studio/src/data/ai-studio-templates.ts

@@ -1,5 +1,6 @@
 import type { TemplateModel } from '@workflowbuilder/sdk';
 
+import { agentHarnessFlow } from './agent-harness-flow';
 import { aiDebateFlow } from './ai-debate-flow';
 import { contentRepurposerFlow } from './content-repurposer-flow';
 import { meetingNotesFlow } from './meeting-notes-flow';
@@ -12,4 +13,5 @@ export const aiStudioTemplates: TemplateModel[] = [
   contentRepurposerFlow,
   meetingNotesFlow,
   researchFlow,
+  agentHarnessFlow,
 ];

apps/ai-studio/src/data/node-types.ts

@@ -1,5 +1,6 @@
 import type { PaletteItemOrGroup } from '@workflowbuilder/sdk';
 
+import { agentHarnessPaletteItem } from '../nodes/agent-harness';
 import { aiAgentPaletteItem } from '../nodes/ai-agent';
 import { decisionPaletteItem } from '../nodes/decision';
 import { triggerPaletteItem } from '../nodes/trigger';
@@ -9,6 +10,12 @@ export const aiStudioNodeTypes: PaletteItemOrGroup[] = [
   {
     label: 'AI Studio',
     isOpen: true,
-    groupItems: [triggerPaletteItem, aiAgentPaletteItem, decisionPaletteItem, visualizePaletteItem],
+    groupItems: [
+      triggerPaletteItem,
+      aiAgentPaletteItem,
+      agentHarnessPaletteItem,
+      decisionPaletteItem,
+      visualizePaletteItem,
+    ],
   },
 ];

apps/ai-studio/src/nodes/agent-harness/default-properties-data.ts

@@ -0,0 +1,15 @@
+import type { NodeDataProperties } from '@workflowbuilder/sdk';
+
+import type { AgentHarnessSchema } from './schema';
+
+export const defaultPropertiesData: NodeDataProperties<AgentHarnessSchema> = {
+  label: 'Agent Harness',
+  description: '',
+  prompt: '',
+  provider: 'copilot',
+  model: 'auto',
+  context: 'fresh',
+  toolsMode: 'none',
+  mutatesCheckout: false,
+  persistSession: false,
+};

apps/ai-studio/src/nodes/agent-harness/index.ts

@@ -0,0 +1,24 @@
+import { NodeType, type PaletteItem } from '@workflowbuilder/sdk';
+
+import { defaultPropertiesData } from './default-properties-data';
+import { type AgentHarnessSchema, schema } from './schema';
+import { uischema } from './uischema';
+
+export const agentHarnessPaletteItem: PaletteItem<AgentHarnessSchema> = {
+  label: 'Agent Harness',
+  description: 'Delegate a step to an autonomous coding-agent CLI (GitHub Copilot)',
+  type: 'ai-studio/agent-harness',
+  icon: 'Terminal',
+  templateType: NodeType.Node,
+  defaultPropertiesData,
+  schema,
+  uischema,
+  // Lets `{{ nodes.<id>.response }}` references resolve to a real mention instead of a "missing mention" pill.
+  outputSchema: {
+    type: 'default',
+    properties: {
+      response: { type: 'string', label: 'Response', description: 'The text produced by the agent run' },
+      tokens: { type: 'object', label: 'Tokens', description: 'Token usage reported by the provider' },
+    },
+  },
+};

apps/ai-studio/src/nodes/agent-harness/schema.ts

@@ -0,0 +1,94 @@
+import { sharedProperties } from '@workflowbuilder/sdk';
+import type { NodeSchema } from '@workflowbuilder/sdk';
+
+// Only Copilot is functionally wired in v1 (see `apps/execution-worker/src/agent-harness/registry.ts`).
+// Kept as a single-entry option list, rather than a plain string, so the Select still renders — a
+// second provider is a one-line addition here once its backend lands (per issue #147 parity intent).
+const providerOptions = [{ label: 'GitHub Copilot', value: 'copilot' }];
+
+// Copilot's own effort ladder (`COPILOT_EFFORTS` in providers/copilot/config.ts) is narrower than the
+// full cross-provider `EffortRung` union — only offer the rungs this provider actually honors.
+const effortOptions = [
+  { label: 'Low', value: 'low' },
+  { label: 'Medium', value: 'medium' },
+  { label: 'High', value: 'high' },
+  { label: 'Extra high', value: 'xhigh' },
+];
+
+// 'shared'/'resume' are NOT YET SUPPORTED (session persistence is out of scope for v1, see the
+// implementation plan §2) — rendered anyway per issue #147 ("fields must still render").
+const contextOptions = [
+  { label: 'Fresh (new session)', value: 'fresh' },
+  { label: 'Shared (not yet supported)', value: 'shared' },
+  { label: 'Resume (not yet supported)', value: 'resume' },
+];
+
+// UI-only convenience preset; expanding it into allowedTools/deniedTools is a manual step for now
+// (no automatic preset -> field wiring in this milestone, see nodes/agent-harness/index.ts handoff).
+const toolsModeOptions = [
+  { label: 'None', value: 'none' },
+  { label: 'Read-only', value: 'read-only' },
+  { label: 'Edit-only', value: 'edit-only' },
+  { label: 'All tools', value: 'all' },
+];
+
+export const schema = {
+  type: 'object',
+  properties: {
+    ...sharedProperties,
+    prompt: {
+      type: 'string',
+    },
+    provider: {
+      type: 'string',
+      options: providerOptions,
+    },
+    model: {
+      type: 'string',
+    },
+    effort: {
+      type: 'string',
+      options: effortOptions,
+    },
+    context: {
+      type: 'string',
+      options: contextOptions,
+    },
+    idle_timeout: {
+      type: 'number',
+    },
+    toolsMode: {
+      type: 'string',
+      options: toolsModeOptions,
+    },
+    allowedTools: {
+      type: 'string',
+    },
+    deniedTools: {
+      type: 'string',
+    },
+    output_format: {
+      type: 'string',
+    },
+    mcp: {
+      type: 'string',
+    },
+    skills: {
+      type: 'string',
+    },
+    agents: {
+      type: 'string',
+    },
+    maxBudgetUsd: {
+      type: 'number',
+    },
+    mutatesCheckout: {
+      type: 'boolean',
+    },
+    persistSession: {
+      type: 'boolean',
+    },
+  },
+} satisfies NodeSchema;
+
+export type AgentHarnessSchema = typeof schema;