diff --git a/src/config/io.ts b/src/config/io.ts
index 4864407976a..be29c72dd74 100644
--- a/src/config/io.ts
+++ b/src/config/io.ts
@@ -215,6 +215,11 @@ export type ConfigWriteOptions = {
    * Normal writers must keep this false so clobbers are rejected before disk commit.
    */
   allowDestructiveWrite?: boolean;
+  /**
+   * Allow an intentional large config size drop while keeping other destructive
+   * guards active. Used by repair flows that remove stale or legacy config.
+   */
+  allowConfigSizeDrop?: boolean;
   /**
    * Suppress human-readable output logs (overwrite/anomaly messages).
    * Useful when the caller wants machine-readable output only (--json mode).
@@ -399,9 +404,14 @@ function resolveConfigWriteSuspiciousReasons(params: {
   return reasons;
 }
 
-function resolveConfigWriteBlockingReasons(suspicious: string[]): string[] {
+function resolveConfigWriteBlockingReasons(
+  suspicious: string[],
+  options: Pick<ConfigWriteOptions, "allowConfigSizeDrop"> = {},
+): string[] {
   return suspicious.filter(
-    (reason) => reason.startsWith("size-drop:") || reason === "gateway-mode-removed",
+    (reason) =>
+      (reason.startsWith("size-drop:") && options.allowConfigSizeDrop !== true) ||
+      reason === "gateway-mode-removed",
   );
 }
 
@@ -2165,7 +2175,7 @@ export function createConfigIO(
         }),
       });
     };
-    const blockingReasons = resolveConfigWriteBlockingReasons(suspiciousReasons);
+    const blockingReasons = resolveConfigWriteBlockingReasons(suspiciousReasons, options);
     if (blockingReasons.length > 0 && options.allowDestructiveWrite !== true) {
       const rejectedPath = `${configPath}.rejected.${formatConfigArtifactTimestamp(new Date().toISOString())}`;
       await deps.fs.promises
@@ -2426,6 +2436,7 @@ export async function writeConfigFile(
     }),
     unsetPaths: resolveManagedUnsetPathsForWrite(options.unsetPaths),
     allowDestructiveWrite: options.allowDestructiveWrite,
+    allowConfigSizeDrop: options.allowConfigSizeDrop,
     skipRuntimeSnapshotRefresh: options.skipRuntimeSnapshotRefresh,
     skipOutputLogs: options.skipOutputLogs,
   });
diff --git a/src/config/io.write-config.test.ts b/src/config/io.write-config.test.ts
index 16095b48372..a3b40fbba32 100644
--- a/src/config/io.write-config.test.ts
+++ b/src/config/io.write-config.test.ts
@@ -602,6 +602,68 @@ describe("config io write", () => {
     });
   });
 
+  it("allows intentional size-drop writes without disabling gateway-mode protection", async () => {
+    await withSuiteHome(async (home) => {
+      const configPath = path.join(home, ".openclaw", "openclaw.json");
+      await fs.mkdir(path.dirname(configPath), { recursive: true });
+      const original = {
+        meta: { lastTouchedVersion: "2026.4.30" },
+        gateway: { mode: "local" },
+        channels: {
+          telegram: {
+            enabled: true,
+            allowFrom: Array.from({ length: 80 }, (_, index) => `telegram:${index}`),
+          },
+        },
+      } satisfies ConfigFileSnapshot["config"];
+      const originalRaw = `${JSON.stringify(original, null, 2)}\n`;
+      await fs.writeFile(configPath, originalRaw, "utf-8");
+      const io = createConfigIO({
+        env: { VITEST: "true" } as NodeJS.ProcessEnv,
+        homedir: () => home,
+        logger: silentLogger,
+      });
+      const baseSnapshot = {
+        path: configPath,
+        exists: true,
+        raw: originalRaw,
+        parsed: original,
+        sourceConfig: original,
+        resolved: original,
+        valid: true,
+        runtimeConfig: original,
+        config: original,
+        issues: [],
+        warnings: [],
+        legacyIssues: [],
+      } satisfies ConfigFileSnapshot;
+
+      await expect(
+        io.writeConfigFile(
+          { meta: original.meta, gateway: { mode: "local" } },
+          {
+            allowConfigSizeDrop: true,
+            baseSnapshot,
+          },
+        ),
+      ).resolves.toMatchObject({
+        persistedConfig: expect.objectContaining({ gateway: { mode: "local" } }),
+      });
+
+      await expect(
+        io.writeConfigFile(
+          { meta: original.meta },
+          {
+            allowConfigSizeDrop: true,
+            baseSnapshot,
+          },
+        ),
+      ).rejects.toMatchObject({
+        code: "CONFIG_WRITE_REJECTED",
+      });
+    });
+  });
+
   it("keeps authored agent provider params during narrowed internal agent writes", async () => {
     await withSuiteHome(async (home) => {
       const configPath = path.join(home, ".openclaw", "openclaw.json");
diff --git a/src/flows/doctor-health-contributions.ts b/src/flows/doctor-health-contributions.ts
index bbdc303a23c..8ffba8d6681 100644
--- a/src/flows/doctor-health-contributions.ts
+++ b/src/flows/doctor-health-contributions.ts
@@ -526,6 +526,9 @@ async function runWriteConfigHealth(ctx: DoctorHealthFlowContext): Promise<void>
     await replaceConfigFile({
       nextConfig: ctx.cfg,
       afterWrite: { mode: "auto" },
+      writeOptions: {
+        allowConfigSizeDrop: ctx.configResult.shouldWriteConfig === true,
+      },
     });
     logConfigUpdated(ctx.runtime);
     const backupPath = `${CONFIG_PATH}.bak`;