diff --git a/src/commands/cliproxy/routing-subcommand.ts b/src/commands/cliproxy/routing-subcommand.ts
index 326a9249..c2272597 100644
--- a/src/commands/cliproxy/routing-subcommand.ts
+++ b/src/commands/cliproxy/routing-subcommand.ts
@@ -173,12 +173,18 @@ export async function handleRoutingAffinityStatus(): Promise<void> {
 export async function handleRoutingAffinitySet(args: string[]): Promise<void> {
   const requested = normalizeCliproxySessionAffinityEnabled(args[0]);
   const extractedTtl = extractOption(args.slice(1), ['--ttl']);
+  const remainingArgs = extractedTtl.remainingArgs.filter((token) => token.trim().length > 0);
   const ttl: string | undefined =
     extractedTtl.found && !extractedTtl.missingValue
       ? (normalizeCliproxySessionAffinityTtl(extractedTtl.value) ?? undefined)
       : undefined;
 
-  if (requested === null || extractedTtl.missingValue || (extractedTtl.found && !ttl)) {
+  if (
+    requested === null ||
+    extractedTtl.missingValue ||
+    (extractedTtl.found && !ttl) ||
+    remainingArgs.length > 0
+  ) {
     await initUI();
     console.log('');
     console.log(
diff --git a/src/commands/completion-backend.ts b/src/commands/completion-backend.ts
index a18ff712..660503af 100644
--- a/src/commands/completion-backend.ts
+++ b/src/commands/completion-backend.ts
@@ -168,11 +168,25 @@ function getSuggestionsForCommand(tokensBeforeCurrent: string[]): CompletionSugg
           '-h',
         ]);
       if (subcommand === 'routing') {
+        const routingSubcommand = tokensBeforeCurrent[2];
+        const routingAffinityMode = tokensBeforeCurrent[3];
         if (lastToken === 'set') {
           return completeSubcommands(['round-robin', 'fill-first']);
         }
-        if (lastToken === 'affinity') {
-          return completeSubcommands(['on', 'off', '--ttl']);
+        if (routingSubcommand === 'affinity') {
+          if (!routingAffinityMode || lastToken === 'affinity') {
+            return completeSubcommands(['on', 'off']);
+          }
+          if (
+            (routingAffinityMode === 'on' || routingAffinityMode === 'off') &&
+            !tokensBeforeCurrent.includes('--ttl')
+          ) {
+            return completeSubcommands([], ['--ttl']);
+          }
+          if (lastToken === '--ttl') {
+            return [];
+          }
+          return completeSubcommands([]);
         }
         return completeSubcommands(['set', 'explain', 'affinity']);
       }
diff --git a/src/config/unified-config-loader.ts b/src/config/unified-config-loader.ts
index 12e348c8..9c4dc5b7 100644
--- a/src/config/unified-config-loader.ts
+++ b/src/config/unified-config-loader.ts
@@ -59,6 +59,8 @@ const CONFIG_YAML = 'config.yaml';
 const CONFIG_JSON = 'config.json';
 const CONFIG_LOCK = 'config.yaml.lock';
 const LOCK_STALE_MS = 5000; // Lock is stale after 5 seconds
+const GO_DURATION_SEGMENT = String.raw`(?:\d+(?:\.\d+)?(?:ns|us|µs|μs|ms|s|m|h))`;
+const GO_DURATION_PATTERN = new RegExp(`^${GO_DURATION_SEGMENT}+$`);
 
 function normalizeBrowserDevtoolsPort(value: number | undefined): number {
   if (!Number.isFinite(value)) {
@@ -112,6 +114,19 @@ function canonicalizeBrowserConfig(
   };
 }
 
+function normalizeSessionAffinityTtl(value: unknown, fallback: string): string {
+  if (typeof value !== 'string') {
+    return fallback;
+  }
+
+  const trimmed = value.trim();
+  if (!trimmed || !GO_DURATION_PATTERN.test(trimmed)) {
+    return fallback;
+  }
+
+  return trimmed;
+}
+
 /**
  * Get path to unified config.yaml
  */
@@ -444,11 +459,10 @@ function mergeWithDefaults(partial: Partial<UnifiedConfig>): UnifiedConfig {
           typeof partial.cliproxy?.routing?.session_affinity === 'boolean'
             ? partial.cliproxy.routing.session_affinity
             : defaults.cliproxy.routing?.session_affinity,
-        session_affinity_ttl:
-          typeof partial.cliproxy?.routing?.session_affinity_ttl === 'string' &&
-          partial.cliproxy.routing.session_affinity_ttl.trim()
-            ? partial.cliproxy.routing.session_affinity_ttl.trim()
-            : defaults.cliproxy.routing?.session_affinity_ttl,
+        session_affinity_ttl: normalizeSessionAffinityTtl(
+          partial.cliproxy?.routing?.session_affinity_ttl,
+          defaults.cliproxy.routing?.session_affinity_ttl ?? '1h'
+        ),
       },
     },
     proxy: {
diff --git a/tests/unit/commands/completion-backend.test.ts b/tests/unit/commands/completion-backend.test.ts
index b683043e..4667dc76 100644
--- a/tests/unit/commands/completion-backend.test.ts
+++ b/tests/unit/commands/completion-backend.test.ts
@@ -128,6 +128,22 @@ describe('completion backend', () => {
     expect(values).toContain('my-codex');
   });
 
+  test('suggests the correct routing affinity completion shape', () => {
+    expect(suggestionValues(['cliproxy', 'routing'])).toEqual(
+      expect.arrayContaining(['set', 'explain', 'affinity'])
+    );
+    expect(suggestionValues(['cliproxy', 'routing', 'affinity'])).toEqual(
+      expect.arrayContaining(['on', 'off'])
+    );
+    expect(suggestionValues(['cliproxy', 'routing', 'affinity', 'on'])).toEqual(
+      expect.arrayContaining(['--ttl'])
+    );
+    expect(suggestionValues(['cliproxy', 'routing', 'affinity', 'off'])).toEqual(
+      expect.arrayContaining(['--ttl'])
+    );
+    expect(suggestionValues(['cliproxy', 'routing', 'affinity', '--ttl'])).not.toContain('--ttl');
+  });
+
   test('suggests env format values after the format flag', () => {
     const values = suggestionValues(['env', '--format']);
     expect(values).toEqual(
diff --git a/tests/unit/unified-config.test.ts b/tests/unit/unified-config.test.ts
index 1fc660c5..8113dae5 100644
--- a/tests/unit/unified-config.test.ts
+++ b/tests/unit/unified-config.test.ts
@@ -285,6 +285,41 @@ describe('continuity-inheritance-config', () => {
   });
 });
 
+describe('cliproxy session-affinity ttl normalization', () => {
+  it('normalizes invalid stored ttl values back to the safe default', () => {
+    const originalCcsHome = process.env.CCS_HOME;
+    const tempHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ccs-affinity-ttl-home-'));
+    const ccsDir = path.join(tempHome, '.ccs');
+    fs.mkdirSync(ccsDir, { recursive: true });
+
+    fs.writeFileSync(
+      path.join(ccsDir, 'config.yaml'),
+      [
+        'version: 8',
+        'cliproxy:',
+        '  routing:',
+        '    strategy: round-robin',
+        '    session_affinity: true',
+        '    session_affinity_ttl: forever',
+        '',
+      ].join('\n')
+    );
+
+    process.env.CCS_HOME = tempHome;
+    try {
+      const config = loadOrCreateUnifiedConfig();
+      expect(config.cliproxy.routing.session_affinity_ttl).toBe('1h');
+    } finally {
+      if (originalCcsHome === undefined) {
+        delete process.env.CCS_HOME;
+      } else {
+        process.env.CCS_HOME = originalCcsHome;
+      }
+      fs.rmSync(tempHome, { recursive: true, force: true });
+    }
+  });
+});
+
 describe('official-channels-config', () => {
   it('keeps explicit channels.selected empty even when legacy discord_channels.enabled is true', () => {
     const originalCcsHome = process.env.CCS_HOME;
diff --git a/ui/src/hooks/use-cliproxy.ts b/ui/src/hooks/use-cliproxy.ts
index c7a58dd0..f8e12a5c 100644
--- a/ui/src/hooks/use-cliproxy.ts
+++ b/ui/src/hooks/use-cliproxy.ts
@@ -90,6 +90,7 @@ export function useUpdateCliproxySessionAffinity() {
     mutationFn: (data: { enabled: boolean; ttl?: string }) =>
       api.cliproxy.updateSessionAffinity(data),
     onSuccess: (result: CliproxySessionAffinityApplyResult) => {
+      queryClient.setQueryData(['cliproxy-session-affinity'], result);
       queryClient.invalidateQueries({ queryKey: ['cliproxy-session-affinity'] });
       const label = result.enabled ? 'enabled' : 'disabled';
       toast.success(result.message || `Session affinity ${label}.`);