diff --git a/.changeset/fifty-lobsters-remain.md b/.changeset/fifty-lobsters-remain.md
new file mode 100644
index 00000000..16b21276
--- /dev/null
+++ b/.changeset/fifty-lobsters-remain.md
@@ -0,0 +1,5 @@
+---
+"@proofkit/cli": patch
+---
+
+Fix FileMaker webviewer init flow to install local addon files before prompting that no FileMaker file is open in the local MCP server.
diff --git a/packages/cli/src/core/context.ts b/packages/cli/src/core/context.ts
index 7a5667e0..ef37bfa7 100644
--- a/packages/cli/src/core/context.ts
+++ b/packages/cli/src/core/context.ts
@@ -164,6 +164,7 @@ export interface FileMakerBootstrapArtifacts {
 
 export interface FileMakerService {
   readonly detectLocalFmMcp: (baseUrl?: string) => Eff<FmMcpStatus, CliError>;
+  readonly installLocalWebViewerAddon: () => Eff<void, CliError>;
   readonly validateHostedServerUrl: (
     serverUrl: string,
     ottoPort?: number | null,
diff --git a/packages/cli/src/core/resolveInitRequest.ts b/packages/cli/src/core/resolveInitRequest.ts
index 832e5e2f..41dcd669 100644
--- a/packages/cli/src/core/resolveInitRequest.ts
+++ b/packages/cli/src/core/resolveInitRequest.ts
@@ -464,6 +464,7 @@ function resolveFileMakerInputs({
 
       while (true) {
         const localFmMcp = yield* fileMakerService.detectLocalFmMcp();
+        yield* fileMakerService.installLocalWebViewerAddon();
         const selectedFile = localFmMcp.healthy ? yield* resolveLocalFmMcpFile(localFmMcp.connectedFiles) : undefined;
         if (localFmMcp.healthy && selectedFile) {
           console.info(`Using local ProofKit MCP file: ${selectedFile}`);
diff --git a/packages/cli/src/services/live.ts b/packages/cli/src/services/live.ts
index cea4082e..d63807ea 100644
--- a/packages/cli/src/services/live.ts
+++ b/packages/cli/src/services/live.ts
@@ -24,6 +24,7 @@ import {
 } from "~/core/context.js";
 import { ExternalCommandError, FileMakerSetupError, FileSystemError, UserCancelledError } from "~/core/errors.js";
 import type { AppType, FileMakerInputs, ProofKitSettings, UIType } from "~/core/types.js";
+import { installFmAddonExplicitly } from "~/installers/install-fm-addon.js";
 import { openBrowser } from "~/utils/browserOpen.js";
 import { deleteJson, getJson, postJson } from "~/utils/http.js";
 import { detectUserPackageManager } from "~/utils/packageManager.js";
@@ -357,6 +358,17 @@ const fileMakerService = {
           cause,
         }),
     }),
+  installLocalWebViewerAddon: () =>
+    Effect.tryPromise({
+      try: async () => {
+        await installFmAddonExplicitly({ addonName: "wv" });
+      },
+      catch: (cause) =>
+        new FileMakerSetupError({
+          message: "Unable to install local ProofKit WebViewer add-on files.",
+          cause,
+        }),
+    }).pipe(Effect.asVoid),
   validateHostedServerUrl: (serverUrl: string, ottoPort?: number | null) =>
     Effect.gen(function* () {
       const normalizedUrl = normalizeUrl(serverUrl);
diff --git a/packages/cli/tests/resolve-init.test.ts b/packages/cli/tests/resolve-init.test.ts
index bbaae7f9..290f1e47 100644
--- a/packages/cli/tests/resolve-init.test.ts
+++ b/packages/cli/tests/resolve-init.test.ts
@@ -392,6 +392,13 @@ describe("resolveInitRequest", () => {
       multiSearchSelect: [],
       confirm: [],
     };
+    const tracker = {
+      commands: [],
+      gitInits: 0,
+      codegens: 0,
+      filemakerBootstraps: 0,
+      addonInstalls: 0,
+    };
 
     const request = await Effect.runPromise(
       resolveInitRequest("demo", {
@@ -408,6 +415,7 @@ describe("resolveInitRequest", () => {
           cwd: "/tmp",
           packageManager: "pnpm",
           nonInteractive: false,
+          tracker,
           prompts: {
             select: ["skip"],
           },
@@ -424,6 +432,7 @@ describe("resolveInitRequest", () => {
 
     expect(request.fileMaker).toBeUndefined();
     expect(request.skipFileMakerSetup).toBe(true);
+    expect(tracker.addonInstalls).toBe(1);
     expect(promptTranscript.select).toContainEqual({
       message:
         "ProofKit MCP Server is running, but no FileMaker file is open yet. Open one, then choose how to continue.",
@@ -439,6 +448,13 @@ describe("resolveInitRequest", () => {
       success: [],
       note: [],
     };
+    const tracker = {
+      commands: [],
+      gitInits: 0,
+      codegens: 0,
+      filemakerBootstraps: 0,
+      addonInstalls: 0,
+    };
 
     const request = await Effect.runPromise(
       resolveInitRequest("demo", {
@@ -455,6 +471,7 @@ describe("resolveInitRequest", () => {
           cwd: "/tmp",
           packageManager: "pnpm",
           nonInteractive: false,
+          tracker,
           prompts: {
             select: ["retry"],
           },
@@ -479,6 +496,7 @@ describe("resolveInitRequest", () => {
       mode: "local-fm-mcp",
       fileName: "RetryConnected.fmp12",
     });
+    expect(tracker.addonInstalls).toBe(2);
     expect(consoleTranscript.info).toContain("Using local ProofKit MCP file: RetryConnected.fmp12");
   });
 
diff --git a/packages/cli/tests/test-layer.ts b/packages/cli/tests/test-layer.ts
index 0624dcb9..ae5650c6 100644
--- a/packages/cli/tests/test-layer.ts
+++ b/packages/cli/tests/test-layer.ts
@@ -64,6 +64,7 @@ export function makeTestLayer(options: {
     gitInits: number;
     codegens: number;
     filemakerBootstraps: number;
+    addonInstalls?: number;
   };
   fileMaker?: {
     localFmMcp?:
@@ -400,6 +401,12 @@ export function makeTestLayer(options: {
           connectedFiles: next?.connectedFiles ?? [],
         });
       },
+      installLocalWebViewerAddon: () => {
+        if (tracker) {
+          tracker.addonInstalls = (tracker.addonInstalls ?? 0) + 1;
+        }
+        return Effect.void;
+      },
       validateHostedServerUrl: (serverUrl: string) => {
         if (options.failures?.validateHostedServerUrl) {
           return Effect.fail(options.failures.validateHostedServerUrl as FileMakerSetupError);