diff --git a/docs/cli/doctor.md b/docs/cli/doctor.md
index 0f91b60bf..994f6a80d 100644
--- a/docs/cli/doctor.md
+++ b/docs/cli/doctor.md
@@ -23,6 +23,7 @@ clawdbot doctor --deep
 
 Notes:
 - Interactive prompts (like keychain/OAuth fixes) only run when stdin is a TTY and `--non-interactive` is **not** set. Headless runs (cron, Telegram, no terminal) will skip prompts.
+- `--fix` (alias for `--repair`) writes a backup to `~/.clawdbot/clawdbot.json.bak` and drops unknown config keys, listing each removal.
 
 ## macOS: `launchctl` env overrides
 
diff --git a/src/commands/doctor-config-flow.test.ts b/src/commands/doctor-config-flow.test.ts
index df7a5a9ee..1f65879b7 100644
--- a/src/commands/doctor-config-flow.test.ts
+++ b/src/commands/doctor-config-flow.test.ts
@@ -34,4 +34,36 @@ describe("doctor config flow", () => {
       });
     });
   });
+
+  it("drops unknown keys on repair", async () => {
+    await withTempHome(async (home) => {
+      const configDir = path.join(home, ".clawdbot");
+      await fs.mkdir(configDir, { recursive: true });
+      await fs.writeFile(
+        path.join(configDir, "clawdbot.json"),
+        JSON.stringify(
+          {
+            bridge: { bind: "auto" },
+            gateway: { auth: { mode: "token", token: "ok", extra: true } },
+            agents: { list: [{ id: "pi" }] },
+          },
+          null,
+          2,
+        ),
+        "utf-8",
+      );
+
+      const result = await loadAndMaybeMigrateDoctorConfig({
+        options: { nonInteractive: true, repair: true },
+        confirm: async () => false,
+      });
+
+      const cfg = result.cfg as Record<string, unknown>;
+      expect(cfg.bridge).toBeUndefined();
+      expect((cfg.gateway as Record<string, unknown>)?.auth).toEqual({
+        mode: "token",
+        token: "ok",
+      });
+    });
+  });
 });
diff --git a/src/commands/doctor-config-flow.ts b/src/commands/doctor-config-flow.ts
index b9deff472..8c2ca9b40 100644
--- a/src/commands/doctor-config-flow.ts
+++ b/src/commands/doctor-config-flow.ts
@@ -1,5 +1,8 @@
+import type { ZodIssue } from "zod";
+
 import type { ClawdbotConfig } from "../config/config.js";
 import {
+  ClawdbotSchema,
   CONFIG_PATH_CLAWDBOT,
   migrateLegacyConfig,
   readConfigFileSnapshot,
@@ -13,6 +16,68 @@ function isRecord(value: unknown): value is Record<string, unknown> {
   return Boolean(value && typeof value === "object" && !Array.isArray(value));
 }
 
+type UnrecognizedKeysIssue = ZodIssue & {
+  code: "unrecognized_keys";
+  keys: string[];
+};
+
+function isUnrecognizedKeysIssue(issue: ZodIssue): issue is UnrecognizedKeysIssue {
+  return issue.code === "unrecognized_keys";
+}
+
+function formatPath(parts: Array<string | number>): string {
+  if (parts.length === 0) return "<root>";
+  let out = "";
+  for (const part of parts) {
+    if (typeof part === "number") {
+      out += `[${part}]`;
+      continue;
+    }
+    out = out ? `${out}.${part}` : part;
+  }
+  return out || "<root>";
+}
+
+function resolvePathTarget(root: unknown, path: Array<string | number>): unknown {
+  let current: unknown = root;
+  for (const part of path) {
+    if (typeof part === "number") {
+      if (!Array.isArray(current)) return null;
+      if (part < 0 || part >= current.length) return null;
+      current = current[part];
+      continue;
+    }
+    if (!current || typeof current !== "object" || Array.isArray(current)) return null;
+    const record = current as Record<string, unknown>;
+    if (!(part in record)) return null;
+    current = record[part];
+  }
+  return current;
+}
+
+function stripUnknownConfigKeys(config: ClawdbotConfig): { config: ClawdbotConfig; removed: string[] } {
+  const parsed = ClawdbotSchema.safeParse(config);
+  if (parsed.success) {
+    return { config, removed: [] };
+  }
+
+  const next = structuredClone(config) as ClawdbotConfig;
+  const removed: string[] = [];
+  for (const issue of parsed.error.issues) {
+    if (!isUnrecognizedKeysIssue(issue)) continue;
+    const target = resolvePathTarget(next, issue.path);
+    if (!target || typeof target !== "object" || Array.isArray(target)) continue;
+    const record = target as Record<string, unknown>;
+    for (const key of issue.keys) {
+      if (!(key in record)) continue;
+      delete record[key];
+      removed.push(formatPath([...issue.path, key]));
+    }
+  }
+
+  return { config: next, removed };
+}
+
 function noteOpencodeProviderOverrides(cfg: ClawdbotConfig) {
   const providers = cfg.models?.providers;
   if (!providers) return;
@@ -89,6 +154,18 @@ export async function loadAndMaybeMigrateDoctorConfig(params: {
     }
   }
 
+  const unknown = stripUnknownConfigKeys(cfg);
+  if (unknown.removed.length > 0) {
+    const lines = unknown.removed.map((path) => `- ${path}`).join("\n");
+    if (shouldRepair) {
+      cfg = unknown.config;
+      note(lines, "Doctor changes");
+    } else {
+      note(lines, "Unknown config keys");
+      note('Run "clawdbot doctor --fix" to remove these keys.', "Doctor");
+    }
+  }
+
   noteOpencodeProviderOverrides(cfg);
 
   return { cfg, path: snapshot.path ?? CONFIG_PATH_CLAWDBOT };
diff --git a/src/commands/doctor.ts b/src/commands/doctor.ts
index c98c234e2..2519bcc0a 100644
--- a/src/commands/doctor.ts
+++ b/src/commands/doctor.ts
@@ -1,3 +1,5 @@
+import fs from "node:fs";
+
 import { intro as clackIntro, outro as clackOutro } from "@clack/prompts";
 import { resolveAgentWorkspaceDir, resolveDefaultAgentId } from "../agents/agent-scope.js";
 import { DEFAULT_MODEL, DEFAULT_PROVIDER } from "../agents/defaults.js";
@@ -251,6 +253,10 @@ export async function doctorCommand(
     cfg = applyWizardMetadata(cfg, { command: "doctor", mode: resolveMode(cfg) });
     await writeConfigFile(cfg);
     runtime.log(`Updated ${CONFIG_PATH_CLAWDBOT}`);
+    const backupPath = `${CONFIG_PATH_CLAWDBOT}.bak`;
+    if (fs.existsSync(backupPath)) {
+      runtime.log(`Backup: ${backupPath}`);
+    }
   } else {
     runtime.log('Run "clawdbot doctor --fix" to apply changes.');
   }