diff --git a/packages/core/src/plugins/anthropic/anthropic.ts b/packages/core/src/plugins/anthropic/anthropic.ts
index e005f5fc3..c679ed5ea 100644
--- a/packages/core/src/plugins/anthropic/anthropic.ts
+++ b/packages/core/src/plugins/anthropic/anthropic.ts
@@ -7,6 +7,9 @@ export type AnthropicModel = {
     completion: number;
   };
   displayName: string;
+
+  /** If true, this model is deprecated/legacy and will be sorted to the bottom of dropdowns. */
+  legacy?: boolean;
 };
 
 export const anthropicModels = {
@@ -17,6 +20,7 @@ export const anthropicModels = {
       completion: 0.00551,
     },
     displayName: 'Claude Instant',
+    legacy: true,
   },
   'claude-instant-1.2': {
     maxTokens: 100_000,
@@ -25,6 +29,7 @@ export const anthropicModels = {
       completion: 2.4e-6,
     },
     displayName: 'Claude Instant 1.2',
+    legacy: true,
   },
   'claude-2': {
     maxTokens: 100_000,
@@ -33,6 +38,7 @@ export const anthropicModels = {
       completion: 24e-6,
     },
     displayName: 'Claude 2',
+    legacy: true,
   },
   'claude-2.1': {
     maxTokens: 200_000,
@@ -41,6 +47,7 @@ export const anthropicModels = {
       completion: 24e-6,
     },
     displayName: 'Claude 2.1',
+    legacy: true,
   },
   'claude-3-haiku-20240307': {
     maxTokens: 200_000,
@@ -49,6 +56,7 @@ export const anthropicModels = {
       completion: 1.25e-6,
     },
     displayName: 'Claude 3 Haiku',
+    legacy: true,
   },
   'claude-3-sonnet-20240229': {
     maxTokens: 200_000,
@@ -57,6 +65,7 @@ export const anthropicModels = {
       completion: 15e-6,
     },
     displayName: 'Claude 3 Sonnet',
+    legacy: true,
   },
   'claude-3-opus-20240229': {
     maxTokens: 200_000,
@@ -65,6 +74,7 @@ export const anthropicModels = {
       completion: 75e-6,
     },
     displayName: 'Claude 3 Opus',
+    legacy: true,
   },
   'claude-3-5-sonnet-latest': {
     maxTokens: 200_000,
@@ -106,14 +116,41 @@ export const anthropicModels = {
     },
     displayName: 'Claude Opus 4',
   },
+  'claude-haiku-4-5-20251001': {
+    maxTokens: 200_000,
+    cost: {
+      prompt: 0.25e-6,
+      completion: 1.25e-6,
+    },
+    displayName: 'Claude Haiku 4.5',
+  },
+  'claude-sonnet-4-6-20260414': {
+    maxTokens: 200_000,
+    cost: {
+      prompt: 3e-6,
+      completion: 15e-6,
+    },
+    displayName: 'Claude Sonnet 4.6',
+  },
+  'claude-opus-4-6-20260414': {
+    maxTokens: 200_000,
+    cost: {
+      prompt: 5e-6,
+      completion: 25e-6,
+    },
+    displayName: 'Claude Opus 4.6',
+  },
 } satisfies Record<string, AnthropicModel>;
 
 export type AnthropicModels = keyof typeof anthropicModels;
 
-export const anthropicModelOptions = Object.entries(anthropicModels).map(([id, { displayName }]) => ({
-  value: id,
-  label: displayName,
-}));
+export const anthropicModelOptions = Object.entries(anthropicModels)
+  .map(([id, model]) => ({
+    value: id,
+    label: model.displayName,
+    legacy: 'legacy' in model ? model.legacy : false,
+  }))
+  .sort((a, b) => Number(a.legacy) - Number(b.legacy) || a.label.localeCompare(b.label));
 
 export type Claude3ChatMessage = {
   role: 'user' | 'assistant';
diff --git a/packages/core/src/plugins/google/google.ts b/packages/core/src/plugins/google/google.ts
index 7afc7c51f..618a9df93 100644
--- a/packages/core/src/plugins/google/google.ts
+++ b/packages/core/src/plugins/google/google.ts
@@ -7,6 +7,9 @@ export type GoogleModelDeprecated = {
     completion: number;
   };
   displayName: string;
+
+  /** If true, this model is deprecated/legacy and will be sorted to the bottom of dropdowns. */
+  legacy?: boolean;
 };
 
 export const googleModelsDeprecated = {
@@ -17,6 +20,7 @@ export const googleModelsDeprecated = {
       completion: NaN,
     },
     displayName: 'Gemini Pro',
+    legacy: true,
   },
   'gemini-pro-vision': {
     maxTokens: 16384,
@@ -25,11 +29,24 @@ export const googleModelsDeprecated = {
       completion: NaN,
     },
     displayName: 'Gemini Pro Vision',
+    legacy: true,
   },
 } satisfies Record<string, GoogleModelDeprecated>;
 
 export type GoogleModelsDeprecated = keyof typeof googleModelsDeprecated;
 
+export type GenerativeAiGoogleModelDef = {
+  maxTokens: number;
+  cost: {
+    prompt: number;
+    completion: number;
+  };
+  displayName: string;
+
+  /** If true, this model is deprecated/legacy and will be sorted to the bottom of dropdowns. */
+  legacy?: boolean;
+};
+
 export const generativeAiGoogleModels = {
   'gemini-2.5-pro': {
     maxTokens: 1048576,
@@ -71,6 +88,30 @@ export const generativeAiGoogleModels = {
     },
     displayName: 'Gemini 2.0 Flash Lite',
   },
+  'gemini-3-1-pro-preview': {
+    maxTokens: 1048576,
+    cost: {
+      prompt: 2.5 / 1000,
+      completion: 15 / 1000,
+    },
+    displayName: 'Gemini 3.1 Pro (Preview)',
+  },
+  'gemini-3-pro-preview': {
+    maxTokens: 1048576,
+    cost: {
+      prompt: 2.0 / 1000,
+      completion: 12 / 1000,
+    },
+    displayName: 'Gemini 3 Pro (Preview)',
+  },
+  'gemini-3-flash-preview': {
+    maxTokens: 1048576,
+    cost: {
+      prompt: 0.5 / 1000,
+      completion: 3 / 1000,
+    },
+    displayName: 'Gemini 3 Flash (Preview)',
+  },
   'gemini-1.5-pro': {
     maxTokens: 2097152,
     cost: {
@@ -78,6 +119,7 @@ export const generativeAiGoogleModels = {
       completion: 0, // It's per-character
     },
     displayName: 'Gemini 1.5 Pro',
+    legacy: true,
   },
   'gemini-1.5-flash': {
     maxTokens: 1048576,
@@ -86,8 +128,9 @@ export const generativeAiGoogleModels = {
       completion: 0, // It's per-character
     },
     displayName: 'Gemini 1.5 Flash',
-  }
-};
+    legacy: true,
+  },
+} satisfies Record<string, GenerativeAiGoogleModelDef>;
 
 export type GenerativeAiGoogleModel = keyof typeof generativeAiGoogleModels;
 
@@ -96,10 +139,13 @@ export const googleModelOptionsDeprecated = Object.entries(googleModelsDeprecate
   label: displayName,
 }));
 
-export const generativeAiOptions = Object.entries(generativeAiGoogleModels).map(([id, { displayName }]) => ({
-  value: id,
-  label: displayName,
-}));
+export const generativeAiOptions = Object.entries(generativeAiGoogleModels)
+  .map(([id, model]) => ({
+    value: id,
+    label: model.displayName,
+    legacy: 'legacy' in model ? model.legacy : false,
+  }))
+  .sort((a, b) => Number(a.legacy) - Number(b.legacy) || a.label.localeCompare(b.label));
 
 export type ChatCompletionOptions = {
   project: string;
diff --git a/packages/core/src/utils/openai.ts b/packages/core/src/utils/openai.ts
index add544a0e..da2b17981 100644
--- a/packages/core/src/utils/openai.ts
+++ b/packages/core/src/utils/openai.ts
@@ -18,6 +18,9 @@ export type OpenAIModel = {
   supported?: {
     parallelFunctionCalls: boolean;
   };
+
+  /** If true, this model is deprecated/legacy and will be sorted to the bottom of dropdowns. */
+  legacy?: boolean;
 };
 
 export const defaultOpenaiSupported: NonNullable<OpenAIModel['supported']> = {
@@ -39,7 +42,7 @@ export const openaiModels = {
   'gpt-5-mini': {
     maxTokens: 400000,
     cost: {
-      prompt: 0.25 - 6,
+      prompt: 0.25e-6,
       completion: 2e-6,
     },
     displayName: 'GPT-5 mini',
@@ -65,6 +68,7 @@ export const openaiModels = {
       completion: 0.015,
     },
     displayName: 'GPT-4o',
+    legacy: true,
   },
   'gpt-4o-mini': {
     maxTokens: 128000,
@@ -73,6 +77,7 @@ export const openaiModels = {
       completion: 0.00075,
     },
     displayName: 'GPT-4o mini',
+    legacy: true,
   },
   o1: {
     maxTokens: 128000,
@@ -84,6 +89,7 @@ export const openaiModels = {
     supported: {
       parallelFunctionCalls: false,
     },
+    legacy: true,
   },
   'o1-mini': {
     maxTokens: 128000,
@@ -95,6 +101,7 @@ export const openaiModels = {
     supported: {
       parallelFunctionCalls: false,
     },
+    legacy: true,
   },
   'o3-mini': {
     maxTokens: 200000,
@@ -116,6 +123,7 @@ export const openaiModels = {
       audioCompletion: 0.08,
     },
     displayName: 'GPT-4o Audio (Preview)',
+    legacy: true,
   },
   'gpt-4.1': {
     maxTokens: 1_047_576,
@@ -141,6 +149,66 @@ export const openaiModels = {
     },
     displayName: 'o4-mini',
   },
+  'gpt-5.1': {
+    maxTokens: 400000,
+    cost: {
+      prompt: 1.25e-6,
+      completion: 10e-6,
+    },
+    displayName: 'GPT-5.1',
+    supported: {
+      parallelFunctionCalls: true,
+    },
+  },
+  'gpt-5.2': {
+    maxTokens: 400000,
+    cost: {
+      prompt: 1.75e-6,
+      completion: 14e-6,
+    },
+    displayName: 'GPT-5.2',
+    supported: {
+      parallelFunctionCalls: true,
+    },
+  },
+  'gpt-5.5': {
+    maxTokens: 400000,
+    cost: {
+      prompt: 2e-6,
+      completion: 16e-6,
+    },
+    displayName: 'GPT-5.5',
+    supported: {
+      parallelFunctionCalls: true,
+    },
+  },
+  'gpt-4.1-mini': {
+    maxTokens: 1_047_576,
+    cost: {
+      prompt: 0.4e-6,
+      completion: 1.6e-6,
+    },
+    displayName: 'GPT-4.1 mini',
+  },
+  'gpt-4.1-nano': {
+    maxTokens: 1_047_576,
+    cost: {
+      prompt: 0.1e-6,
+      completion: 0.4e-6,
+    },
+    displayName: 'GPT-4.1 nano',
+  },
+  'o3-pro': {
+    maxTokens: 200_000,
+    cost: {
+      prompt: 20e-6,
+      completion: 80e-6,
+    },
+    displayName: 'o3-pro',
+    supported: {
+      parallelFunctionCalls: false,
+    },
+  },
   'local-model': {
     maxTokens: Number.MAX_SAFE_INTEGER,
     cost: {
@@ -152,11 +220,12 @@ export const openaiModels = {
 } satisfies Record<string, OpenAIModel>;
 
 export const openAiModelOptions = orderBy(
-  Object.entries(openaiModels).map(([id, { displayName }]) => ({
+  Object.entries(openaiModels).map(([id, model]) => ({
     value: id,
-    label: displayName,
+    label: model.displayName,
+    legacy: 'legacy' in model ? model.legacy : false,
   })),
-  'label',
+  ['legacy', 'label'],
 );
 
 export class OpenAIError extends Error {
diff --git a/packages/core/test/models.test.ts b/packages/core/test/models.test.ts
new file mode 100644
index 000000000..9f993f405
--- /dev/null
+++ b/packages/core/test/models.test.ts
@@ -0,0 +1,115 @@
+import { describe, it } from 'node:test';
+import { strict as assert } from 'node:assert';
+import { openaiModels, openAiModelOptions } from '../src/utils/openai.js';
+import { anthropicModels, anthropicModelOptions } from '../src/plugins/anthropic/anthropic.js';
+import {
+  generativeAiGoogleModels,
+  generativeAiOptions,
+  googleModelsDeprecated,
+} from '../src/plugins/google/google.js';
+
+describe('OpenAI models', () => {
+  it('every model has required fields with valid values', () => {
+    for (const [id, model] of Object.entries(openaiModels)) {
+      assert.ok(model.displayName, `${id} missing displayName`);
+      assert.ok(typeof model.maxTokens === 'number' && model.maxTokens > 0, `${id} has invalid maxTokens`);
+      assert.ok(typeof model.cost.prompt === 'number', `${id} has invalid prompt cost`);
+      assert.ok(typeof model.cost.completion === 'number', `${id} has invalid completion cost`);
+      assert.ok(model.cost.prompt >= 0, `${id} has negative prompt cost`);
+      assert.ok(model.cost.completion >= 0, `${id} has negative completion cost`);
+    }
+  });
+
+  it('has no duplicate model IDs', () => {
+    const ids = Object.keys(openaiModels);
+    const unique = new Set(ids);
+    assert.strictEqual(ids.length, unique.size, 'Duplicate OpenAI model IDs found');
+  });
+
+  it('dropdown options have no duplicates', () => {
+    const values = openAiModelOptions.map((o) => o.value);
+    assert.strictEqual(values.length, new Set(values).size, 'Duplicate dropdown values');
+  });
+
+  it('legacy models are sorted to the bottom of dropdown', () => {
+    const legacyStart = openAiModelOptions.findIndex((o) => o.legacy);
+    if (legacyStart === -1) return; // no legacy models, nothing to check
+    const allAfterLegacyStart = openAiModelOptions.slice(legacyStart);
+    assert.ok(
+      allAfterLegacyStart.every((o) => o.legacy),
+      'Non-legacy model found after first legacy model in dropdown',
+    );
+  });
+
+  it('prompt cost is not accidentally a subtraction (regression for 0.25-6 vs 0.25e-6)', () => {
+    for (const [id, model] of Object.entries(openaiModels)) {
+      if (id === 'local-model') continue;
+      assert.ok(model.cost.prompt < 1, `${id} prompt cost ${model.cost.prompt} looks too high — possible math error`);
+      assert.ok(
+        model.cost.completion < 1,
+        `${id} completion cost ${model.cost.completion} looks too high — possible math error`,
+      );
+    }
+  });
+});
+
+describe('Anthropic models', () => {
+  it('every model has required fields with valid values', () => {
+    for (const [id, model] of Object.entries(anthropicModels)) {
+      assert.ok(model.displayName, `${id} missing displayName`);
+      assert.ok(typeof model.maxTokens === 'number' && model.maxTokens > 0, `${id} has invalid maxTokens`);
+      assert.ok(typeof model.cost.prompt === 'number', `${id} has invalid prompt cost`);
+      assert.ok(typeof model.cost.completion === 'number', `${id} has invalid completion cost`);
+      assert.ok(model.cost.prompt >= 0, `${id} has negative prompt cost`);
+      assert.ok(model.cost.completion >= 0, `${id} has negative completion cost`);
+    }
+  });
+
+  it('has no duplicate model IDs', () => {
+    const ids = Object.keys(anthropicModels);
+    assert.strictEqual(ids.length, new Set(ids).size, 'Duplicate Anthropic model IDs found');
+  });
+
+  it('legacy models are sorted to the bottom of dropdown', () => {
+    const legacyStart = anthropicModelOptions.findIndex((o) => o.legacy);
+    if (legacyStart === -1) return;
+    const allAfterLegacyStart = anthropicModelOptions.slice(legacyStart);
+    assert.ok(
+      allAfterLegacyStart.every((o) => o.legacy),
+      'Non-legacy model found after first legacy model in dropdown',
+    );
+  });
+});
+
+describe('Google Gemini models', () => {
+  it('every generative AI model has required fields with valid values', () => {
+    for (const [id, model] of Object.entries(generativeAiGoogleModels)) {
+      assert.ok(model.displayName, `${id} missing displayName`);
+      assert.ok(typeof model.maxTokens === 'number' && model.maxTokens > 0, `${id} has invalid maxTokens`);
+      assert.ok(typeof model.cost.prompt === 'number', `${id} has invalid prompt cost`);
+      assert.ok(typeof model.cost.completion === 'number', `${id} has invalid completion cost`);
+    }
+  });
+
+  it('deprecated models still have required fields', () => {
+    for (const [id, model] of Object.entries(googleModelsDeprecated)) {
+      assert.ok(model.displayName, `${id} missing displayName`);
+      assert.ok(typeof model.maxTokens === 'number' && model.maxTokens > 0, `${id} has invalid maxTokens`);
+    }
+  });
+
+  it('has no duplicate model IDs', () => {
+    const ids = Object.keys(generativeAiGoogleModels);
+    assert.strictEqual(ids.length, new Set(ids).size, 'Duplicate Google model IDs found');
+  });
+
+  it('legacy models are sorted to the bottom of dropdown', () => {
+    const legacyStart = generativeAiOptions.findIndex((o) => o.legacy);
+    if (legacyStart === -1) return;
+    const allAfterLegacyStart = generativeAiOptions.slice(legacyStart);
+    assert.ok(
+      allAfterLegacyStart.every((o) => o.legacy),
+      'Non-legacy model found after first legacy model in dropdown',
+    );
+  });
+});