diff --git a/CHANGELOG.md b/CHANGELOG.md
index d5fcc49..c04d971 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -42,6 +42,16 @@ platform API version.
 
 ### Added
 
+- **A product whose CLI has no `run` says so: `cliRuns: false`.** The
+  toolkit then registers no run driver and the chat offers no resume. The
+  webview learns it from a derived `clientBehavior.runDriver` (like
+  `chatBackend`; `resumeAtStep` is now derived with it), and a diagram with no
+  run driver behind it shows no Run, Stop or edge toggle in the palette
+  header and no Agent Tools switches in the property panel, all of which
+  called the driver's commands. That covers ndf once it opts out, and today
+  chisel-ide and the library-mode mlir-viewer, whose Run invoked a command
+  nothing registered. sv and vhdl keep theirs: `hdl run` simulates through
+  it.
 - **A product's own webview bundle starts the stock diagram.**
   `startStockDiagram({ features })` (`@dialogram/diagram-client/stock-starter`)
   is what the stock bundle runs, with the product's feature modules loaded
diff --git a/packages/diagram-client/src/profile.ts b/packages/diagram-client/src/profile.ts
index 7d26ea4..af03573 100644
--- a/packages/diagram-client/src/profile.ts
+++ b/packages/diagram-client/src/profile.ts
@@ -78,6 +78,22 @@ export function clientBehavior(): DiagramClientBehavior {
     return configured && typeof configured === 'object' ? configured : {};
 }
 
+/**
+ * Whether the diagram offers what drives a run: Run, Stop, the toggle for what
+ * a run puts on the edges, and the agent-tool switches the run driver serves.
+ * Yes unless the host says no run driver is behind it; a webview the host did
+ * not describe (dev, standalone) keeps them, as before.
+ */
+export function offersRun(): boolean {
+    return clientBehavior().runDriver !== false;
+}
+
+/** The run controls the palette header adds, by {@link offersRun}. */
+export function runHeaderControls(): { run: boolean; stop: boolean; edgeToggle: boolean } {
+    const runs = offersRun();
+    return { run: runs, stop: runs, edgeToggle: runs };
+}
+
 /**
  * The host resolves part of the behavior after the webview is up (what depends
  * on the machine or the workspace, e.g. the ACP connectors the runtime knows)
diff --git a/packages/diagram-client/src/property-panel.ts b/packages/diagram-client/src/property-panel.ts
index df46318..fe8d96f 100644
--- a/packages/diagram-client/src/property-panel.ts
+++ b/packages/diagram-client/src/property-panel.ts
@@ -33,7 +33,7 @@ import { VscodeUi } from './vscode-ui';
 import { ppField, ppNumberField, ppReadonlyRow, renderInto } from './property-fields';
 import { type PropertyElement, readNumberArg } from './property-model';
 import { PropertyPanelChrome } from './property-panel-chrome';
-import { clientBehavior, commandId, operationKind } from './profile';
+import { clientBehavior, commandId, operationKind, offersRun } from './profile';
 import { classifyLink, decodeURIComponentSafe, openTargetOf, referenceAction, type PanelLink } from './open-target';
 import { producerFields, type ProducerField } from './producer-fields';
 
@@ -577,8 +577,9 @@ export class PropertyPanel implements ISelectionListener, IGModelRootListener {
             content.appendChild(this.buildDefinitionAnnotationsSection(node.id, args, undefined, requestAgentDiscovery));
         }
 
-        // Agent Tools section (only rendered for @agent nodes)
-        const agentToolsSection = this.buildAgentToolsSection(entityName, args);
+        // Agent Tools section (only rendered for @agent nodes, and only where a run
+        // driver is behind the diagram: its two commands are the driver's).
+        const agentToolsSection = offersRun() ? this.buildAgentToolsSection(entityName, args) : null;
         if (agentToolsSection) {
             content.appendChild(agentToolsSection);
         }
diff --git a/packages/diagram-client/src/tool-palette-header-controls.ts b/packages/diagram-client/src/tool-palette-header-controls.ts
index c2524ba..8047b2e 100644
--- a/packages/diagram-client/src/tool-palette-header-controls.ts
+++ b/packages/diagram-client/src/tool-palette-header-controls.ts
@@ -1,7 +1,7 @@
 import { codiconCSSClasses } from '@eclipse-glsp/sprotty';
 import { VscodeUi } from './vscode-ui';
 import { exportDiagramSvg } from './svg-export-command';
-import { commandId, feedbackEdgesVisibleStorageKey, queueTraceVisibleStorageKey } from './profile';
+import { commandId, feedbackEdgesVisibleStorageKey, queueTraceVisibleStorageKey, runHeaderControls } from './profile';
 
 type DiagramContext = {
     sourceUri?: string;
@@ -169,6 +169,7 @@ async function exec(command: string, args: unknown[] = []): Promise<void> {
 }
 
 function patchHeaderTools(headerTools: HTMLElement): void {
+    const offered = runHeaderControls();
     // 1) Replace reset-viewport behavior: screen-normal -> fit + center
     const resetIcon = headerTools.querySelector('i.codicon.codicon-screen-normal') as HTMLElement | null;
     if (resetIcon) {
@@ -182,8 +183,8 @@ function patchHeaderTools(headerTools: HTMLElement): void {
         };
     }
 
-    // 2) Add Run button as first header tool.
-    if (!headerTools.querySelector('i.codicon.codicon-play.cal-run-workflow')) {
+    // 2) Add Run button as first header tool, when something runs the diagram.
+    if (offered.run && !headerTools.querySelector('i.codicon.codicon-play.cal-run-workflow')) {
         const runIcon = createHeaderIcon('play');
         runIcon.classList.add('cal-run-workflow');
         runIcon.title = 'Run workflow';
@@ -209,8 +210,8 @@ function patchHeaderTools(headerTools: HTMLElement): void {
         headerTools.insertBefore(runIcon, headerTools.firstChild);
     }
 
-    // 3) Add Stop button to cancel an active workflow run.
-    if (!headerTools.querySelector('i.codicon.codicon-debug-stop.cal-stop-workflow')) {
+    // 3) Add Stop button to cancel an active workflow run, under the same condition.
+    if (offered.stop && !headerTools.querySelector('i.codicon.codicon-debug-stop.cal-stop-workflow')) {
         const stopIcon = createHeaderIcon('debug-stop');
         stopIcon.classList.add('cal-stop-workflow');
         stopIcon.title = 'Stop workflow run';
@@ -225,8 +226,8 @@ function patchHeaderTools(headerTools: HTMLElement): void {
         headerTools.insertBefore(stopIcon, headerTools.firstChild);
     }
 
-    // 4) Add queue visibility toggle icon.
-    if (!headerTools.querySelector('i.cal-toggle-queues')) {
+    // 4) Add queue visibility toggle icon: what a run puts on the edges, so only where something runs.
+    if (offered.edgeToggle && !headerTools.querySelector('i.cal-toggle-queues')) {
         const queueIcon = createHeaderIcon('eye');
         queueIcon.classList.add('cal-toggle-queues');
 
diff --git a/packages/diagram-client/test/offers-run.test.ts b/packages/diagram-client/test/offers-run.test.ts
new file mode 100644
index 0000000..9e75aa8
--- /dev/null
+++ b/packages/diagram-client/test/offers-run.test.ts
@@ -0,0 +1,31 @@
+/**
+ * What drives a run is offered unless the host says no run driver is behind
+ * the diagram. The palette header adds Run, Stop and the edge toggle by
+ * {@link runHeaderControls}; the property panel shows the agent-tool switches
+ * by {@link offersRun}. (The client tests run without a DOM, so the header's
+ * own wiring is not exercised here.)
+ */
+import { afterEach, describe, expect, it } from 'vitest';
+import { offersRun, runHeaderControls } from '../src/profile';
+
+afterEach(() => {
+    delete (globalThis as any).diagramIdentifier;
+});
+
+describe('the run controls', () => {
+    it('are gone when the host says no run driver is behind the diagram', () => {
+        (globalThis as any).diagramIdentifier = { clientBehavior: { runDriver: false } };
+        expect(offersRun()).toBe(false);
+        expect(runHeaderControls()).toEqual({ run: false, stop: false, edgeToggle: false });
+    });
+
+    it('are there when one is', () => {
+        (globalThis as any).diagramIdentifier = { clientBehavior: { runDriver: true } };
+        expect(offersRun()).toBe(true);
+        expect(runHeaderControls()).toEqual({ run: true, stop: true, edgeToggle: true });
+    });
+
+    it('stay in a webview the host did not describe', () => {
+        expect(offersRun()).toBe(true);
+    });
+});
diff --git a/packages/extension-core/src/extension/diagram/diagram-editor-provider.ts b/packages/extension-core/src/extension/diagram/diagram-editor-provider.ts
index 88b5352..879abae 100644
--- a/packages/extension-core/src/extension/diagram/diagram-editor-provider.ts
+++ b/packages/extension-core/src/extension/diagram/diagram-editor-provider.ts
@@ -990,6 +990,11 @@ export class WorkflowEditorProvider extends GlspEditorProvider {
                 // absent is exactly what "the chat backend is not activated"
                 // means, so it is the honest source.
                 chatBackend: this.profile.chat !== undefined,
+                // The same for the run driver: Run and Stop are offered exactly
+                // when something is registered to run the diagram, and a run is
+                // resumable only where something can run it again.
+                runDriver: this.profile.runDriver !== undefined,
+                resumeAtStep: this.profile.clientBehavior?.resumeAtStep === true && this.profile.runDriver !== undefined,
                 // The same for the status source: the menu offers exactly the
                 // commands the host registered, or none. Data only; `collect`
                 // stays on the host.
diff --git a/packages/extension-core/test/diagram-editor-provider-client-assets.test.ts b/packages/extension-core/test/diagram-editor-provider-client-assets.test.ts
index ea5467f..6717041 100644
--- a/packages/extension-core/test/diagram-editor-provider-client-assets.test.ts
+++ b/packages/extension-core/test/diagram-editor-provider-client-assets.test.ts
@@ -168,7 +168,7 @@ describe('WorkflowEditorProvider default webview assets (no clientAssets)', () =
               <script nonce="NONCE">
                   // Pass diagram identifier to the client. Serialized as one JSON literal
                   // with '<' escaped so no value (e.g. a URI) can break out of the script.
-                  window.diagramIdentifier = {"clientId":"client-0","diagramType":"cal-network-diagram","uri":"file:///workspace/pipeline.py","settingsNamespace":"test","clientBehavior":{"chatBackend":false},"libavoidWasmUri":"https://webview/fake-ext/dist/webview/libavoid.wasm","libavoidModuleUri":"https://webview/fake-ext/dist/webview/libavoid.mjs"};
+                  window.diagramIdentifier = {"clientId":"client-0","diagramType":"cal-network-diagram","uri":"file:///workspace/pipeline.py","settingsNamespace":"test","clientBehavior":{"chatBackend":false,"runDriver":false,"resumeAtStep":false},"libavoidWasmUri":"https://webview/fake-ext/dist/webview/libavoid.wasm","libavoidModuleUri":"https://webview/fake-ext/dist/webview/libavoid.mjs"};
 
                   // Edge route/bendpoint overlay (WorkflowEdgeView), a purely visual
                   // client-side debug aid injected from the extension host (launch.json env).
diff --git a/packages/extension-core/test/diagram-editor-provider-status-source.test.ts b/packages/extension-core/test/diagram-editor-provider-derived-behavior.test.ts
similarity index 75%
rename from packages/extension-core/test/diagram-editor-provider-status-source.test.ts
rename to packages/extension-core/test/diagram-editor-provider-derived-behavior.test.ts
index 5590783..1d7d9f4 100644
--- a/packages/extension-core/test/diagram-editor-provider-status-source.test.ts
+++ b/packages/extension-core/test/diagram-editor-provider-derived-behavior.test.ts
@@ -74,3 +74,22 @@ describe('the status source, as the webview sees it', () => {
         expect(clientBehaviorFor(PROFILE)).not.toHaveProperty('statusSource');
     });
 });
+
+describe('the run driver, as the webview sees it', () => {
+    it('is there exactly when the profile has one, so Run and Stop are offered only then', () => {
+        const runDriver = (() => ({ dispose() {} })) as unknown as DiagramProfile['runDriver'];
+        expect(clientBehaviorFor({ ...PROFILE, runDriver }).runDriver).toBe(true);
+        expect(clientBehaviorFor(PROFILE).runDriver).toBe(false);
+    });
+
+    it('is the platform\'s to say, whatever the product wrote', () => {
+        const behavior = clientBehaviorFor({ ...PROFILE, clientBehavior: { runDriver: true } as any });
+        expect(behavior.runDriver).toBe(false);
+    });
+
+    it('takes resuming with it: nothing could run the resumed run', () => {
+        const runDriver = (() => ({ dispose() {} })) as unknown as DiagramProfile['runDriver'];
+        expect(clientBehaviorFor({ ...PROFILE, runDriver, clientBehavior: { resumeAtStep: true } as any }).resumeAtStep).toBe(true);
+        expect(clientBehaviorFor({ ...PROFILE, clientBehavior: { resumeAtStep: true } as any }).resumeAtStep).toBe(false);
+    });
+});
diff --git a/packages/shared/src/client-behavior.ts b/packages/shared/src/client-behavior.ts
index cc67890..30311ab 100644
--- a/packages/shared/src/client-behavior.ts
+++ b/packages/shared/src/client-behavior.ts
@@ -114,12 +114,20 @@ export interface DiagramClientBehavior {
      * write it.
      */
     statusSource?: { label: string; showCommand: string; clearCommand: string };
+    /**
+     * Whether a run driver is behind this diagram: the Run and Stop buttons are
+     * offered exactly then. Derived by the platform from `DiagramProfile.runDriver`,
+     * like {@link chatBackend}; read it, do not write it. A button that invokes a
+     * command nothing registered, or a CLI subcommand that does not exist, is
+     * worse than no button.
+     */
+    runDriver?: boolean;
 }
 
 /**
- * The fields a product may set. The other four ({@link DiagramClientBehavior.chatBackend},
- * `acpConnectors`, `resumeAtStep`, `statusSource`) the platform derives on
- * the way to the webview; a product-facing type that declared them would
- * invite setting them by hand, the one way the two halves could disagree.
+ * The fields a product may set. The other five ({@link DiagramClientBehavior.chatBackend},
+ * `acpConnectors`, `resumeAtStep`, `statusSource`, `runDriver`) the platform
+ * derives on the way to the webview; a product-facing type that declared them
+ * would invite setting them by hand, the one way the two halves could disagree.
  */
-export type ProductClientBehavior = Omit<DiagramClientBehavior, 'chatBackend' | 'acpConnectors' | 'resumeAtStep' | 'statusSource'>;
+export type ProductClientBehavior = Omit<DiagramClientBehavior, 'chatBackend' | 'acpConnectors' | 'resumeAtStep' | 'statusSource' | 'runDriver'>;
diff --git a/packages/sidecar-toolkit/src/sidecar-diagram-profile.ts b/packages/sidecar-toolkit/src/sidecar-diagram-profile.ts
index 6e842c6..8d0ba3b 100644
--- a/packages/sidecar-toolkit/src/sidecar-diagram-profile.ts
+++ b/packages/sidecar-toolkit/src/sidecar-diagram-profile.ts
@@ -166,6 +166,14 @@ export interface SidecarProfileInput {
      * it; without it the stepper offers no resume.
      */
     cliResumeArgs?: (runDir: string, step: number) => string[];
+    /**
+     * Whether the product's CLI runs a diagram (`<cli> run <file> --out-dir ...`),
+     * which the toolkit's run driver calls. Default `true`. `false` for a
+     * product whose CLI has no `run`: no run driver is registered, the
+     * diagram offers no Run, Stop, run toggle or agent-tool switches, the chat
+     * offers no resume, and the run-driver setting keys are not read.
+     */
+    cliRuns?: boolean;
 
     // User-visible strings / behavior.
     /** Appended to every undo label. Default ` (<key>)`. */
@@ -628,11 +636,13 @@ export function createSidecarDiagramProfile(givenInput: SidecarProfileInput) {
     // A product that can resume runs gives the chat a way to offer it: the
     // agent that fixed a failed run proposes resuming it, and the person says
     // yes or no.
-    if (input.cliResumeArgs) {
+    // A run can only be resumed, or driven at all, where the CLI runs one.
+    const runs = input.cliRuns !== false;
+    if (runs && input.cliResumeArgs) {
         chatTools.push(resumeFailedRunTool(input.commands.runWorkflow));
     }
 
-    const runDriver = (context: vscode.ExtensionContext, host: RunHost): vscode.Disposable => {
+    const runDriver = runs ? (context: vscode.ExtensionContext, host: RunHost): vscode.Disposable => {
         const config: CliRunDriverConfig = {
             settingsNamespace: input.settingsNamespace,
             customEditorViewType: input.customEditorViewType,
@@ -680,7 +690,7 @@ export function createSidecarDiagramProfile(givenInput: SidecarProfileInput) {
             onSignature: (listener) => driver.onLiveOverlaySignature(listener)
         });
         return { dispose: () => driver.dispose() };
-    };
+    } : undefined;
 
     const newSourceFile = (context: vscode.ExtensionContext): vscode.Disposable => {
         // The raw sidecar commands need a sidecar; a read-only profile has none.
@@ -726,7 +736,7 @@ export function createSidecarDiagramProfile(givenInput: SidecarProfileInput) {
         // A projection creates nothing, whatever the input says.
         supportsElementCreation: readOnly ? false : input.supportsElementCreation,
         operationKinds: input.operationKinds,
-        clientBehavior: input.cliResumeArgs
+        clientBehavior: runs && input.cliResumeArgs
             ? { ...input.clientBehavior, resumeAtStep: true }
             : input.clientBehavior,
         clientStylesheets: input.clientStylesheets,
diff --git a/packages/sidecar-toolkit/test/sidecar-diagram-profile.test.ts b/packages/sidecar-toolkit/test/sidecar-diagram-profile.test.ts
index 3c40084..749d322 100644
--- a/packages/sidecar-toolkit/test/sidecar-diagram-profile.test.ts
+++ b/packages/sidecar-toolkit/test/sidecar-diagram-profile.test.ts
@@ -170,6 +170,18 @@ describe('createSidecarDiagramProfile', () => {
         expect(withResume.clientBehavior).toMatchObject({ noneSentinel: 'x', resumeAtStep: true });
     });
 
+    it('builds no run driver, offers no resume, for a product whose CLI has no run', () => {
+        const resume = (runDir: string, step: number) => ['--resume-from', runDir, '--at-step', String(step)];
+        const runs = createSidecarDiagramProfile(baseInput({ cliResumeArgs: resume }));
+        expect(typeof runs.runDriver).toBe('function');
+        expect(runs.chat?.tools?.map(t => t.name)).toContain('resume_failed_run');
+
+        const none = createSidecarDiagramProfile(baseInput({ cliRuns: false, cliResumeArgs: resume }));
+        expect(none.runDriver).toBeUndefined();
+        expect((none.clientBehavior as any)?.resumeAtStep).toBeUndefined();
+        expect(none.chat?.tools?.map(t => t.name)).not.toContain('resume_failed_run');
+    });
+
     it('leaves the creation palette alone unless the product suppresses it', () => {
         // Default `true` by omission, so the assembler cannot silently empty the
         // palette of a product that never mentioned it.