diff --git a/eslint.config.js b/eslint.config.js
index 996d1fc0f20..696eb9f1577 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -12,7 +12,7 @@ import prettierConfig from 'eslint-config-prettier';
 import importPlugin from 'eslint-plugin-import';
 import vitest from '@vitest/eslint-plugin';
 import globals from 'globals';
-import licenseHeader from 'eslint-plugin-license-header';
+import headers from 'eslint-plugin-headers';
 import path from 'node:path';
 import url from 'node:url';
 
@@ -209,19 +209,26 @@ export default tseslint.config(
   {
     files: ['./**/*.{tsx,ts,js}'],
     plugins: {
-      'license-header': licenseHeader,
+      headers,
       import: importPlugin,
     },
     rules: {
-      'license-header/header': [
+      'headers/header-format': [
         'error',
-        [
-          '/**',
-          ' * @license',
-          ' * Copyright 2025 Google LLC',
-          ' * SPDX-License-Identifier: Apache-2.0',
-          ' */',
-        ],
+        {
+          source: 'string',
+          content: [
+            '@license',
+            'Copyright (year) Google LLC',
+            'SPDX-License-Identifier: Apache-2.0',
+          ].join('\n'),
+          patterns: {
+            year: {
+              pattern: '202[5-6]',
+              defaultValue: '2026',
+            },
+          },
+        },
       ],
       'import/enforce-node-protocol-usage': ['error', 'always'],
     },
diff --git a/package-lock.json b/package-lock.json
index 09d38da588b..b34d8560584 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -36,8 +36,8 @@
         "esbuild-plugin-wasm": "^1.1.0",
         "eslint": "^9.24.0",
         "eslint-config-prettier": "^10.1.2",
+        "eslint-plugin-headers": "^1.3.3",
         "eslint-plugin-import": "^2.31.0",
-        "eslint-plugin-license-header": "^0.8.0",
         "eslint-plugin-react": "^7.37.5",
         "eslint-plugin-react-hooks": "^5.2.0",
         "glob": "^12.0.0",
@@ -8865,6 +8865,19 @@
         "ms": "^2.1.1"
       }
     },
+    "node_modules/eslint-plugin-headers": {
+      "version": "1.3.3",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-headers/-/eslint-plugin-headers-1.3.3.tgz",
+      "integrity": "sha512-VzZY4+cGRoR5HpALLARH+ibIjB6a2w12/cFEayORHXMRHMzDnweSjpmvxyzX3rsSIVCg01zmvepB7Tnmaj4kGQ==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": "^16.0.0 || >= 18.0.0"
+      },
+      "peerDependencies": {
+        "eslint": ">=7"
+      }
+    },
     "node_modules/eslint-plugin-import": {
       "version": "2.32.0",
       "resolved": "https://registry.npmjs.org/eslint-plugin-import/-/eslint-plugin-import-2.32.0.tgz",
@@ -8919,16 +8932,6 @@
         "semver": "bin/semver.js"
       }
     },
-    "node_modules/eslint-plugin-license-header": {
-      "version": "0.8.0",
-      "resolved": "https://registry.npmjs.org/eslint-plugin-license-header/-/eslint-plugin-license-header-0.8.0.tgz",
-      "integrity": "sha512-khTCz6G3JdoQfwrtY4XKl98KW4PpnWUKuFx8v+twIRhJADEyYglMDC0td8It75C1MZ88gcvMusWuUlJsos7gYg==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "requireindex": "^1.2.0"
-      }
-    },
     "node_modules/eslint-plugin-react": {
       "version": "7.37.5",
       "resolved": "https://registry.npmjs.org/eslint-plugin-react/-/eslint-plugin-react-7.37.5.tgz",
@@ -15069,16 +15072,6 @@
       "dev": true,
       "license": "MIT"
     },
-    "node_modules/requireindex": {
-      "version": "1.2.0",
-      "resolved": "https://registry.npmjs.org/requireindex/-/requireindex-1.2.0.tgz",
-      "integrity": "sha512-L9jEkOi3ASd9PYit2cwRfyppc9NoABujTP8/5gFcbERmo5jUoAKovIC3fsF17pkTnGsrByysqX+Kxd2OTNI1ww==",
-      "dev": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">=0.10.5"
-      }
-    },
     "node_modules/requires-port": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/requires-port/-/requires-port-1.0.0.tgz",
diff --git a/package.json b/package.json
index 973f356e11e..44ac64b26d5 100644
--- a/package.json
+++ b/package.json
@@ -94,8 +94,8 @@
     "esbuild-plugin-wasm": "^1.1.0",
     "eslint": "^9.24.0",
     "eslint-config-prettier": "^10.1.2",
+    "eslint-plugin-headers": "^1.3.3",
     "eslint-plugin-import": "^2.31.0",
-    "eslint-plugin-license-header": "^0.8.0",
     "eslint-plugin-react": "^7.37.5",
     "eslint-plugin-react-hooks": "^5.2.0",
     "glob": "^12.0.0",
diff --git a/packages/core/src/core/client.ts b/packages/core/src/core/client.ts
index c1d7f7c9a1c..0fcc8b5ab17 100644
--- a/packages/core/src/core/client.ts
+++ b/packages/core/src/core/client.ts
@@ -57,6 +57,7 @@ import {
   applyModelSelection,
   createAvailabilityContextProvider,
 } from '../availability/policyHelpers.js';
+import { resolveModel } from '../config/models.js';
 import type { RetryAvailabilityContext } from '../utils/retry.js';
 
 const MAX_TURNS = 100;
@@ -397,7 +398,7 @@ export class GeminiClient {
 
     // Availability logic: The configured model is the source of truth,
     // including any permanent fallbacks (config.setModel) or manual overrides.
-    return this.config.getActiveModel();
+    return resolveModel(this.config.getActiveModel());
   }
 
   async *sendMessageStream(
diff --git a/packages/core/src/utils/tokenCalculation.test.ts b/packages/core/src/utils/tokenCalculation.test.ts
index 7e1eae3e88d..c6e54bc8870 100644
--- a/packages/core/src/utils/tokenCalculation.test.ts
+++ b/packages/core/src/utils/tokenCalculation.test.ts
@@ -123,8 +123,26 @@ describe('calculateRequestTokenCount', () => {
 
     // Should fallback to estimation:
     // 'Hello': 5 chars * 0.25 = 1.25
-    // inlineData: JSON.stringify length / 4
-    expect(count).toBeGreaterThan(0);
+    // inlineData: 3000
+    // Total: 3001.25 -> 3001
+    expect(count).toBe(3001);
     expect(mockContentGenerator.countTokens).toHaveBeenCalled();
   });
+
+  it('should use fixed estimate for images in fallback', async () => {
+    vi.mocked(mockContentGenerator.countTokens).mockRejectedValue(
+      new Error('API error'),
+    );
+    const request = [
+      { inlineData: { mimeType: 'image/png', data: 'large_data' } },
+    ];
+
+    const count = await calculateRequestTokenCount(
+      request,
+      mockContentGenerator,
+      model,
+    );
+
+    expect(count).toBe(3000);
+  });
 });
diff --git a/packages/core/src/utils/tokenCalculation.ts b/packages/core/src/utils/tokenCalculation.ts
index 0359cb3e7c0..06292bb9254 100644
--- a/packages/core/src/utils/tokenCalculation.ts
+++ b/packages/core/src/utils/tokenCalculation.ts
@@ -6,6 +6,7 @@
 
 import type { PartListUnion, Part } from '@google/genai';
 import type { ContentGenerator } from '../core/contentGenerator.js';
+import { debugLogger } from './debugLogger.js';
 
 // Token estimation constants
 // ASCII characters (0-127) are roughly 4 chars per token
@@ -13,6 +14,8 @@ const ASCII_TOKENS_PER_CHAR = 0.25;
 // Non-ASCII characters (including CJK) are often 1-2 tokens per char.
 // We use 1.3 as a conservative estimate to avoid underestimation.
 const NON_ASCII_TOKENS_PER_CHAR = 1.3;
+// Fixed token estimate for images
+const IMAGE_TOKEN_ESTIMATE = 3000;
 
 /**
  * Estimates token count for parts synchronously using a heuristic.
@@ -31,10 +34,21 @@ export function estimateTokenCountSync(parts: Part[]): number {
         }
       }
     } else {
-      // For non-text parts (functionCall, functionResponse, executableCode, etc.),
-      // we fallback to the JSON string length heuristic.
-      // Note: This is an approximation.
-      totalTokens += JSON.stringify(part).length / 4;
+      // For images, we use a fixed safe estimate (3,000 tokens) covering
+      // up to 4K resolution on Gemini 3.
+      // See: https://ai.google.dev/gemini-api/docs/vision#token_counting
+      const inlineData = 'inlineData' in part ? part.inlineData : undefined;
+      const fileData = 'fileData' in part ? part.fileData : undefined;
+      const mimeType = inlineData?.mimeType || fileData?.mimeType;
+
+      if (mimeType?.startsWith('image/')) {
+        totalTokens += IMAGE_TOKEN_ESTIMATE;
+      } else {
+        // For other non-text parts (functionCall, functionResponse, etc.),
+        // we fallback to the JSON string length heuristic.
+        // Note: This is an approximation.
+        totalTokens += JSON.stringify(part).length / 4;
+      }
     }
   }
   return Math.floor(totalTokens);
@@ -69,8 +83,9 @@ export async function calculateRequestTokenCount(
         contents: [{ role: 'user', parts }],
       });
       return response.totalTokens ?? 0;
-    } catch {
+    } catch (error) {
       // Fallback to local estimation if the API call fails
+      debugLogger.debug('countTokens API failed:', error);
       return estimateTokenCountSync(parts);
     }
   }
diff --git a/scripts/generate-git-commit-info.js b/scripts/generate-git-commit-info.js
index 75c8bb97ba3..049c39c249b 100644
--- a/scripts/generate-git-commit-info.js
+++ b/scripts/generate-git-commit-info.js
@@ -57,7 +57,7 @@ try {
 
 const fileContent = `/**
  * @license
- * Copyright ${new Date().getFullYear()} Google LLC
+ * Copyright ${new Date().getUTCFullYear()} Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */