diff --git a/README.md b/README.md
index 3df20538..572d0394 100644
--- a/README.md
+++ b/README.md
@@ -94,11 +94,22 @@ Commands:
   skills                 Manage WorkOS skills for coding agents (install, uninstall, list)
   mcp                    Manage the WorkOS MCP server in coding agents
   setup                  Set up WorkOS skills and the MCP server
+```
+
+**Nothing is installed into your coding agents without explicit opt-in.** The CLI never silently writes skills or MCP configuration into `~/.claude`, `~/.cursor`, etc. After `workos login` or `workos install`, an interactive session may offer to set up your agents — the prompt defaults to **No**, and declining (or running non-interactively) installs nothing. To opt in at any time:
+
+```bash
+workos setup            # interactive setup (skills + MCP server)
+workos setup --yes      # non-interactive opt-in
+workos skills install   # skills only
+workos mcp install      # MCP server only
+```
 
-`workos setup` installs WorkOS skills and configures the MCP server only after consent. Use `workos skills list` to check skill status, `workos mcp status` to check whether the server definition is configured, or `workos doctor --fix` to refresh stale skills.
+Use `workos skills list` to check skill status, `workos mcp status` to check whether the server definition is configured, or `workos doctor --fix` to refresh stale skills you previously installed.
 
 MCP configuration and OAuth authentication are separate states. The WorkOS CLI never inspects a coding agent's credentials, so "configured" means the server definition is in place — it cannot prove that OAuth is usable in any agent. Each agent owns its own OAuth; with Codex, for example, complete or refresh it with `codex mcp login workos` in your normal host shell. See the [WorkOS MCP setup and recovery guide](https://workos.com/docs/mcp) for user-global and trusted-project-only configuration.
 
+```text
 Resource Management:
   organization (org)     Manage organizations
   user                   Manage users
diff --git a/src/commands/setup.spec.ts b/src/commands/setup.spec.ts
index 28593d6b..f92324bc 100644
--- a/src/commands/setup.spec.ts
+++ b/src/commands/setup.spec.ts
@@ -203,6 +203,15 @@ describe('runSetup — automatic triggers (login/install)', () => {
     expect(prefs.recordSetupCompleted).not.toHaveBeenCalled();
   });
 
+  it('defaults the consent prompt to No (AUTH-6734: install is explicit opt-in)', async () => {
+    detectSome();
+    vi.mocked(ui.confirm).mockResolvedValue(false);
+
+    await runSetup({ trigger: 'login' });
+
+    expect(ui.confirm).toHaveBeenCalledWith(expect.objectContaining({ initialValue: false }));
+  });
+
   it('records an absolute decline and installs nothing on "no"', async () => {
     detectSome();
     vi.mocked(ui.confirm).mockResolvedValue(false);
@@ -214,6 +223,19 @@ describe('runSetup — automatic triggers (login/install)', () => {
     expect(prefs.recordSetupCompleted).not.toHaveBeenCalled();
   });
 
+  it('prints manual-install instructions when the user declines', async () => {
+    detectSome();
+    vi.mocked(ui.confirm).mockResolvedValue(false);
+
+    await runSetup({ trigger: 'login' });
+
+    const hints = vi.mocked(ui.log.hint).mock.calls.map(([msg]) => String(msg));
+    expect(hints.some((m) => m.includes('Nothing was installed'))).toBe(true);
+    expect(hints.some((m) => m.includes('workos setup'))).toBe(true);
+    expect(hints.some((m) => m.includes('workos skills install'))).toBe(true);
+    expect(hints.some((m) => m.includes('workos mcp install'))).toBe(true);
+  });
+
   it('treats cancel (ctrl-c) as skip — no decline recorded, but emits a cancelled event', async () => {
     detectSome();
     vi.mocked(ui.confirm).mockResolvedValue(CANCEL);
@@ -307,6 +329,17 @@ describe('runSetup — command trigger', () => {
     expect(prefs.recordSetupDeclined).not.toHaveBeenCalled();
   });
 
+  it('scopes the decline instructions to what was offered', async () => {
+    vi.mocked(detectAgents).mockReturnValue([claudeAgent as any]);
+    vi.mocked(ui.confirm).mockResolvedValue(false);
+
+    await runSetup({ trigger: 'command', skillsOnly: true });
+
+    const hints = vi.mocked(ui.log.hint).mock.calls.map(([msg]) => String(msg));
+    expect(hints.some((m) => m.includes('workos skills install'))).toBe(true);
+    expect(hints.some((m) => m.includes('workos mcp install'))).toBe(false);
+  });
+
   it('skillsOnly skips MCP detection/install', async () => {
     vi.mocked(detectAgents).mockReturnValue([claudeAgent as any]);
     vi.mocked(ui.confirm).mockResolvedValue(true);
diff --git a/src/commands/setup.ts b/src/commands/setup.ts
index 668e858a..efd2a6aa 100644
--- a/src/commands/setup.ts
+++ b/src/commands/setup.ts
@@ -15,6 +15,11 @@
  * The consent contract is the whole point: nothing is written to a coding agent
  * unless the user says yes (or passes --yes). This replaces the auto-install
  * that a customer called "prompt injection malware".
+ *
+ * AUTH-6734 policy: never install silently. The consent prompt defaults to No,
+ * so an absent-minded Enter (or any non-answer) installs nothing; the only ways
+ * anything lands are an explicit "yes" at the prompt or an explicit flag
+ * (`workos setup --yes`, `workos skills install`, `workos mcp install`).
  */
 
 import { homedir } from 'node:os';
@@ -144,7 +149,9 @@ export async function runSetup(opts: RunSetupOptions): Promise<void> {
         `scaffold auth and manage WorkOS resources. Nothing is written until you confirm.`,
     );
 
-    const answer = await ui.confirm({ message: 'Set up now?', initialValue: true });
+    // Default MUST stay No (AUTH-6734): installation is opt-in only, so the
+    // default answer — what an impatient Enter produces — installs nothing.
+    const answer = await ui.confirm({ message: 'Set up now?', initialValue: false });
     // Cancel (ctrl-c) is not a decline — skip silently and ask again next time,
     // but record it so the cut-off is observable in telemetry.
     if (isCancel(answer)) {
@@ -154,7 +161,7 @@ export async function runSetup(opts: RunSetupOptions): Promise<void> {
     if (!answer) {
       if (!isCommand) recordSetupDeclined();
       emitSetupEvent(opts.trigger, startedAt, 'declined', { skills: [], mcpInstalled: [], mcpFailed: [] });
-      ui.log.hint(`No problem. Run \`${formatWorkOSCommand('setup')}\` anytime.`);
+      printManualInstallInstructions(wantSkills, wantMcp);
       return;
     }
   }
@@ -209,6 +216,24 @@ async function installAndReport(
   reportResults(skillResult ? { agents: skillAgentNames, count: skillResult.skills.length } : null, mcpResults);
 }
 
+/**
+ * A decline is the safe default, not a dead end (AUTH-6734): always leave the
+ * exact manual-install commands behind so opting in later is self-serve.
+ * Scoped to what the offer actually covered (--skills-only / --mcp-only).
+ */
+function printManualInstallInstructions(wantSkills: boolean, wantMcp: boolean): void {
+  ui.log.hint('Nothing was installed. To install later, run any of:');
+  if (wantSkills && wantMcp) {
+    ui.log.hint(`  ${formatWorkOSCommand('setup')}           skills + MCP server`);
+  }
+  if (wantSkills) {
+    ui.log.hint(`  ${formatWorkOSCommand('skills install')}  skills only`);
+  }
+  if (wantMcp) {
+    ui.log.hint(`  ${formatWorkOSCommand('mcp install')}     MCP server only`);
+  }
+}
+
 interface SkillSummary {
   agents: string[];
   count: number;