diff --git a/packages/core/src/ai/__tests__/thinking.test.ts b/packages/core/src/ai/__tests__/thinking.test.ts
index 50d5c7d4..33eab472 100644
--- a/packages/core/src/ai/__tests__/thinking.test.ts
+++ b/packages/core/src/ai/__tests__/thinking.test.ts
@@ -3,12 +3,19 @@ import { describe, it } from 'node:test'
 import { getSupportedThinkingLevels, getThinkingCompat, isReasoningModel } from '../thinking'
 
 describe('isReasoningModel', () => {
-  it('returns false for anthropic provider (out of scope v1)', () => {
+  it('returns false for anthropic provider (out of scope)', () => {
     assert.equal(isReasoningModel('anthropic', 'claude-opus-4-6'), false)
   })
 
-  it('returns false for gemini provider (out of scope v1)', () => {
-    assert.equal(isReasoningModel('gemini', 'gemini-2.5-pro'), false)
+  it('returns true for gemini 2.5+ reasoning models', () => {
+    assert.equal(isReasoningModel('gemini', 'gemini-2.5-pro'), true)
+    assert.equal(isReasoningModel('gemini', 'gemini-2.5-flash-preview-05-20'), true)
+    assert.equal(isReasoningModel('gemini', 'gemini-3-flash'), true)
+  })
+
+  it('returns false for older gemini models', () => {
+    assert.equal(isReasoningModel('gemini', 'gemini-2.0-flash'), false)
+    assert.equal(isReasoningModel('gemini', 'gemini-1.5-pro'), false)
   })
 
   it('returns true for qwen provider', () => {
@@ -19,6 +26,11 @@ describe('isReasoningModel', () => {
     assert.equal(isReasoningModel('deepseek', 'deepseek-v4-pro'), true)
   })
 
+  it('returns true for deepseek hybrid (v3.x / chat)', () => {
+    assert.equal(isReasoningModel('deepseek', 'deepseek-chat'), true)
+    assert.equal(isReasoningModel('deepseek', 'deepseek-v3.1'), true)
+  })
+
   it('returns true for openai o-series', () => {
     assert.equal(isReasoningModel('openai', 'o3'), true)
   })
@@ -34,6 +46,38 @@ describe('isReasoningModel', () => {
   it('returns false for non-reasoning model (gpt-4o)', () => {
     assert.equal(isReasoningModel('openai', 'gpt-4o'), false)
   })
+
+  it('returns false for models with -non-reasoning suffix', () => {
+    assert.equal(isReasoningModel('xai', 'grok-4-fast-non-reasoning'), false)
+  })
+
+  it('returns true for hunyuan reasoning models', () => {
+    assert.equal(isReasoningModel('hunyuan', 'hunyuan-t1-latest'), true)
+    assert.equal(isReasoningModel('tencent', 'hunyuan-a13b'), true)
+  })
+
+  it('returns true for known reasoning model families', () => {
+    assert.equal(isReasoningModel('minimax', 'minimax-m2'), true)
+    assert.equal(isReasoningModel('baichuan', 'baichuan-m3'), true)
+    assert.equal(isReasoningModel('mistral', 'mistral-small-2603'), true)
+    assert.equal(isReasoningModel('step', 'step-3'), true)
+    assert.equal(isReasoningModel('google', 'gemma-4-27b'), true)
+    assert.equal(isReasoningModel('perplexity', 'sonar-deep-research'), true)
+    assert.equal(isReasoningModel('xiaomi', 'mimo-v2-flash'), true)
+    assert.equal(isReasoningModel('bytedance', 'seed-oss-36b'), true)
+  })
+
+  it('returns true for kimi k2.5+ models', () => {
+    assert.equal(isReasoningModel('kimi', 'kimi-k2.5'), true)
+    assert.equal(isReasoningModel('kimi', 'kimi-k3'), true)
+  })
+
+  it('returns true for grok reasoning variants', () => {
+    assert.equal(isReasoningModel('xai', 'grok-3-mini'), true)
+    assert.equal(isReasoningModel('xai', 'grok-4'), true)
+    assert.equal(isReasoningModel('xai', 'grok-4-fast'), true)
+    assert.equal(isReasoningModel('xai', 'grok-build'), true)
+  })
 })
 
 describe('getSupportedThinkingLevels', () => {
@@ -41,51 +85,110 @@ describe('getSupportedThinkingLevels', () => {
     assert.deepEqual(getSupportedThinkingLevels('openai', 'gpt-4o'), [])
   })
 
-  it('returns [] for anthropic (out of scope v1)', () => {
+  it('returns [] for anthropic (out of scope)', () => {
     assert.deepEqual(getSupportedThinkingLevels('anthropic', 'claude-opus-4-6'), [])
   })
 
-  it('returns off+high for qwen (on/off only)', () => {
-    assert.deepEqual(getSupportedThinkingLevels('qwen', 'qwen3-max'), ['off', 'high'])
+  it('always includes default as first option for reasoning models', () => {
+    const levels = getSupportedThinkingLevels('qwen', 'qwen3-max')
+    assert.equal(levels[0], 'default')
   })
 
-  it('returns off+high for glm (zai, same as qwen)', () => {
-    assert.deepEqual(getSupportedThinkingLevels('glm', 'glm-5'), ['off', 'high'])
+  it('returns default+off+high for qwen (on/off only)', () => {
+    assert.deepEqual(getSupportedThinkingLevels('qwen', 'qwen3-max'), ['default', 'off', 'high'])
   })
 
-  it('returns off+high+xhigh for deepseek-v4', () => {
-    assert.deepEqual(getSupportedThinkingLevels('deepseek', 'deepseek-v4-pro'), ['off', 'high', 'xhigh'])
+  it('returns default+off+high for glm (same as qwen)', () => {
+    assert.deepEqual(getSupportedThinkingLevels('glm', 'glm-5'), ['default', 'off', 'high'])
   })
 
-  it('returns low+medium+high for o-series (cannot disable)', () => {
-    assert.deepEqual(getSupportedThinkingLevels('openai', 'o3'), ['low', 'medium', 'high'])
+  it('returns default+off+high+xhigh for deepseek-v4', () => {
+    assert.deepEqual(getSupportedThinkingLevels('deepseek', 'deepseek-v4-pro'), ['default', 'off', 'high', 'xhigh'])
   })
 
-  it('returns full range for gpt-5.2+', () => {
-    assert.deepEqual(
-      getSupportedThinkingLevels('openai', 'gpt-5.2'),
-      ['off', 'minimal', 'low', 'medium', 'high', 'xhigh'],
-    )
+  it('returns default+off+auto for deepseek hybrid', () => {
+    assert.deepEqual(getSupportedThinkingLevels('deepseek', 'deepseek-chat'), ['default', 'off', 'auto'])
   })
 
-  it('returns minimal+low+medium+high for gpt-5 base (cannot disable)', () => {
-    assert.deepEqual(getSupportedThinkingLevels('openai', 'gpt-5'), ['minimal', 'low', 'medium', 'high'])
+  it('returns default+low+medium+high for o-series (cannot disable)', () => {
+    assert.deepEqual(getSupportedThinkingLevels('openai', 'o3'), ['default', 'low', 'medium', 'high'])
   })
 
-  it('returns off+high for self-hosted qwen3 (qwen type)', () => {
-    assert.deepEqual(getSupportedThinkingLevels('openai-compatible', 'qwen3:8b'), ['off', 'high'])
+  it('returns full range with default for gpt-5.2+', () => {
+    assert.deepEqual(getSupportedThinkingLevels('openai', 'gpt-5.2'), [
+      'default',
+      'off',
+      'minimal',
+      'low',
+      'medium',
+      'high',
+      'xhigh',
+    ])
   })
 
-  it('returns low+medium+high for kimi thinking models', () => {
-    assert.deepEqual(getSupportedThinkingLevels('kimi', 'kimi-k2-thinking'), ['low', 'medium', 'high'])
+  it('returns default+minimal+low+medium+high for gpt-5 base (cannot disable)', () => {
+    assert.deepEqual(getSupportedThinkingLevels('openai', 'gpt-5'), ['default', 'minimal', 'low', 'medium', 'high'])
   })
 
-  it('returns high only for doubao seed (no disable support)', () => {
-    assert.deepEqual(getSupportedThinkingLevels('doubao', 'doubao-seed-2-0-pro-260215'), ['high'])
+  it('returns default+off+high for self-hosted qwen3 (qwen type)', () => {
+    assert.deepEqual(getSupportedThinkingLevels('openai-compatible', 'qwen3:8b'), ['default', 'off', 'high'])
   })
 
-  it('returns low+high for grok (cannot disable)', () => {
-    assert.deepEqual(getSupportedThinkingLevels('xai', 'grok-4'), ['low', 'high'])
+  it('returns default+off+auto+low+medium+high for kimi thinking models', () => {
+    assert.deepEqual(getSupportedThinkingLevels('kimi', 'kimi-k2-thinking'), [
+      'default',
+      'off',
+      'auto',
+      'low',
+      'medium',
+      'high',
+    ])
+  })
+
+  it('returns default+off+auto+high for doubao seed', () => {
+    assert.deepEqual(getSupportedThinkingLevels('doubao', 'doubao-seed-2-0-pro-260215'), [
+      'default',
+      'off',
+      'auto',
+      'high',
+    ])
+  })
+
+  it('returns default+low+high for grok (cannot disable)', () => {
+    assert.deepEqual(getSupportedThinkingLevels('xai', 'grok-4'), ['default', 'low', 'high'])
+  })
+
+  it('returns default+off+high for hunyuan', () => {
+    assert.deepEqual(getSupportedThinkingLevels('hunyuan', 'hunyuan-t1-latest'), ['default', 'off', 'high'])
+  })
+
+  it('returns default+off+low+medium+high for gemini 2.5+', () => {
+    assert.deepEqual(getSupportedThinkingLevels('gemini', 'gemini-2.5-flash-preview-05-20'), [
+      'default',
+      'off',
+      'low',
+      'medium',
+      'high',
+    ])
+    assert.deepEqual(getSupportedThinkingLevels('gemini', 'gemini-3-pro'), ['default', 'off', 'low', 'medium', 'high'])
+  })
+
+  it('returns empty for older gemini models', () => {
+    assert.deepEqual(getSupportedThinkingLevels('gemini', 'gemini-2.0-flash'), [])
+  })
+
+  it('returns default+off+auto for mimo (deepseek_hybrid type)', () => {
+    assert.deepEqual(getSupportedThinkingLevels('openai-compatible', 'mimo-v2-flash'), ['default', 'off', 'auto'])
+  })
+
+  it('returns default+off+low+medium+high for generic reasoning (fallback)', () => {
+    assert.deepEqual(getSupportedThinkingLevels('openai-compatible', 'some-reasoning-model'), [
+      'default',
+      'off',
+      'low',
+      'medium',
+      'high',
+    ])
   })
 })
 
@@ -98,17 +201,19 @@ describe('getThinkingCompat', () => {
     assert.deepEqual(getThinkingCompat('qwen', 'qwen3-max'), { thinkingFormat: 'qwen' })
   })
 
-  it('returns thinkingFormat:qwen for glm (zai)', () => {
+  it('returns thinkingFormat:qwen for glm', () => {
     assert.deepEqual(getThinkingCompat('glm', 'glm-5'), { thinkingFormat: 'qwen' })
   })
 
+  it('returns thinkingFormat:qwen for hunyuan', () => {
+    assert.deepEqual(getThinkingCompat('tencent', 'hunyuan-a13b'), { thinkingFormat: 'qwen' })
+  })
+
   it('returns thinkingFormat:qwen for self-hosted qwen3', () => {
     assert.deepEqual(getThinkingCompat('openai-compatible', 'qwen3:8b'), { thinkingFormat: 'qwen' })
   })
 
-  it('returns thinkingFormat:deepseek + thinkingLevelMap for deepseek-v4 (KEY FIX)', () => {
-    // DeepSeek needs thinkingFormat:'deepseek' so pi-ai sends thinking:{type:"disabled"}
-    // when 'off' is selected — NOT the generic supportsReasoningEffort path.
+  it('returns thinkingFormat:deepseek + thinkingLevelMap for deepseek-v4', () => {
     const compat = getThinkingCompat('deepseek', 'deepseek-v4-pro')
     assert.equal(compat.thinkingFormat, 'deepseek')
     assert.equal(compat.supportsReasoningEffort, undefined)
@@ -117,6 +222,14 @@ describe('getThinkingCompat', () => {
     assert.equal(compat.thinkingLevelMap?.minimal, null)
   })
 
+  it('returns thinkingFormat:deepseek + auto mapping for deepseek hybrid', () => {
+    const compat = getThinkingCompat('deepseek', 'deepseek-chat')
+    assert.equal(compat.thinkingFormat, 'deepseek')
+    assert.equal(compat.thinkingLevelMap?.auto, 'auto')
+    assert.equal(compat.thinkingLevelMap?.high, 'high')
+    assert.equal(compat.thinkingLevelMap?.xhigh, null)
+  })
+
   it('returns supportsReasoningEffort for o-series', () => {
     const compat = getThinkingCompat('openai', 'o3')
     assert.equal(compat.supportsReasoningEffort, true)
@@ -135,4 +248,28 @@ describe('getThinkingCompat', () => {
     assert.equal(compat.thinkingLevelMap?.off, 'none')
     assert.equal(compat.thinkingLevelMap?.xhigh, 'xhigh')
   })
+
+  it('returns supportsReasoningEffort + auto/off mappings for kimi', () => {
+    const compat = getThinkingCompat('kimi', 'kimi-k2-thinking')
+    assert.equal(compat.supportsReasoningEffort, true)
+    assert.equal(compat.thinkingLevelMap?.auto, 'auto')
+    assert.equal(compat.thinkingLevelMap?.off, 'none')
+  })
+
+  it('returns supportsReasoningEffort + auto mapping for doubao', () => {
+    const compat = getThinkingCompat('doubao', 'doubao-seed-2-0-pro-260215')
+    assert.equal(compat.supportsReasoningEffort, true)
+    assert.equal(compat.thinkingLevelMap?.auto, 'auto')
+    assert.equal(compat.thinkingLevelMap?.high, 'high')
+  })
+
+  it('returns thinkingFormat:deepseek for mimo/minimax/seed-oss (thinking:{type} format)', () => {
+    const compat = getThinkingCompat('openai-compatible', 'mimo-v2-flash')
+    assert.equal(compat.thinkingFormat, 'deepseek')
+    assert.equal(compat.thinkingLevelMap?.auto, 'auto')
+    assert.equal(compat.thinkingLevelMap?.high, 'high')
+
+    const compat2 = getThinkingCompat('minimax', 'minimax-m2')
+    assert.equal(compat2.thinkingFormat, 'deepseek')
+  })
 })
diff --git a/packages/core/src/ai/thinking.ts b/packages/core/src/ai/thinking.ts
index e9d9d296..d6057cac 100644
--- a/packages/core/src/ai/thinking.ts
+++ b/packages/core/src/ai/thinking.ts
@@ -6,52 +6,56 @@
  *   - which models support thinking and at what granularity
  *   - what `compat` fields pi-ai needs to actually inject the right request params
  *
- * Scope (v1): openai-completions API path only.
+ * Scope: openai-completions API path only.
  * anthropic-messages / google-generative-ai are out of scope for this version.
  */
 
 // ── Types ─────────────────────────────────────────────────────────────────────
 
-/** Ordered from off (weakest) to xhigh (strongest), mirrors pi-ai's enum. */
-export type ThinkingLevel = 'off' | 'minimal' | 'low' | 'medium' | 'high' | 'xhigh'
+/**
+ * ThinkingLevel values the UI selector can display.
+ * - 'default': no reasoning params sent — rely on model's native default behavior
+ * - 'off': explicitly disable reasoning
+ * - 'auto': let the model flexibly decide reasoning intensity
+ * - others: specific intensity levels
+ */
+export type ThinkingLevel = 'default' | 'off' | 'minimal' | 'low' | 'medium' | 'high' | 'xhigh' | 'auto'
 
 /** Used internally to categorise a model into a thinking behaviour group. */
 type ThinkingType =
-  | 'none'          // model is not a reasoning model
-  | 'qwen'          // Qwen-family: boolean enable_thinking (off/on)
-  | 'deepseek_v4'   // DeepSeek V4+: thinkingFormat:'deepseek', off/high/xhigh
-  | 'o_series'      // OpenAI o1/o3: can't disable thinking; low/medium/high only
-  | 'gpt5'          // OpenAI gpt-5 base: can't disable; minimal/low/medium/high
-  | 'gpt5_1'        // OpenAI gpt-5.1: off→none supported; off/low/medium/high
-  | 'gpt5_2plus'    // OpenAI gpt-5.2+: off→none + xhigh; full range
-  | 'grok'          // xAI grok: can't disable; low/high only
-  | 'kimi'          // Kimi thinking: low/medium/high
-  | 'doubao'        // Doubao seed reasoning: high only (no disable support)
-  | 'default'       // generic reasoning: off / low / medium / high
+  | 'none' // model is not a reasoning model
+  | 'qwen' // Qwen/GLM-family: boolean enable_thinking (off/on)
+  | 'deepseek_v4' // DeepSeek V4+: thinkingFormat:'deepseek', off/high/xhigh
+  | 'deepseek_hybrid' // DeepSeek V3.x hybrid inference: supports auto
+  | 'o_series' // OpenAI o1/o3: can't disable thinking; low/medium/high only
+  | 'gpt5' // OpenAI gpt-5 base: can't disable; minimal/low/medium/high
+  | 'gpt5_1' // OpenAI gpt-5.1: off→none supported; off/low/medium/high
+  | 'gpt5_2plus' // OpenAI gpt-5.2+: off→none + xhigh; full range
+  | 'grok' // xAI grok: can't disable; low/high only
+  | 'kimi' // Kimi thinking: off/auto/low/medium/high
+  | 'doubao' // Doubao seed reasoning: off/auto/high
+  | 'hunyuan' // Hunyuan: enable_thinking boolean, similar to qwen
+  | 'gemini' // Gemini 2.5+: thinking level via Google API (off/low/medium/high)
+  | 'default' // generic reasoning: off / low / medium / high
 
 // ── Internal: per-type level tables ──────────────────────────────────────────
 
 /** UI options for each type — what the selector will show. */
 const TYPE_LEVELS: Record<ThinkingType, ThinkingLevel[]> = {
-  none:        [],
-  // Qwen/GLM: boolean enable_thinking; 'off' sends false, 'high' sends true
-  qwen:        ['off', 'high'],
-  // DeepSeek V4+: thinkingFormat:'deepseek', 'off' → thinking:{type:"disabled"}
-  deepseek_v4: ['off', 'high', 'xhigh'],
-  // o-series: always thinks, no API param to disable; don't show 'off'
-  o_series:    ['low', 'medium', 'high'],
-  // gpt-5 base: API doesn't support reasoning_effort:'none'; no 'off'
-  gpt5:        ['minimal', 'low', 'medium', 'high'],
-  // gpt-5.1+: supports reasoning_effort:'none' to disable thinking
-  gpt5_1:      ['off', 'low', 'medium', 'high'],
-  gpt5_2plus:  ['off', 'minimal', 'low', 'medium', 'high', 'xhigh'],
-  // Grok: no disable support; only low/high
-  grok:        ['low', 'high'],
-  // Kimi: low/medium/high (no confirmed disable API)
-  kimi:        ['low', 'medium', 'high'],
-  // Doubao: only 'high' confirmed; no disable
-  doubao:      ['high'],
-  default:     ['off', 'low', 'medium', 'high'],
+  none: [],
+  qwen: ['default', 'off', 'high'],
+  deepseek_v4: ['default', 'off', 'high', 'xhigh'],
+  deepseek_hybrid: ['default', 'off', 'auto'],
+  o_series: ['default', 'low', 'medium', 'high'],
+  gpt5: ['default', 'minimal', 'low', 'medium', 'high'],
+  gpt5_1: ['default', 'off', 'low', 'medium', 'high'],
+  gpt5_2plus: ['default', 'off', 'minimal', 'low', 'medium', 'high', 'xhigh'],
+  grok: ['default', 'low', 'high'],
+  kimi: ['default', 'off', 'auto', 'low', 'medium', 'high'],
+  doubao: ['default', 'off', 'auto', 'high'],
+  hunyuan: ['default', 'off', 'high'],
+  gemini: ['default', 'off', 'low', 'medium', 'high'],
+  default: ['default', 'off', 'low', 'medium', 'high'],
 }
 
 /**
@@ -60,69 +64,94 @@ const TYPE_LEVELS: Record<ThinkingType, ThinkingLevel[]> = {
  * `undefined` (key absent) means pass the level string verbatim.
  * Matches pi-ai's convention in models.generated.js.
  */
-// thinkingLevelMap is only used by models on the supportsReasoningEffort path.
-// DeepSeek uses thinkingFormat:'deepseek' (its own pi-ai branch) and has no entry here.
 const TYPE_LEVEL_MAP: Partial<Record<ThinkingType, Partial<Record<ThinkingLevel, string | null>>>> = {
   gpt5: {
     minimal: 'minimal',
-    low:     'low',
-    medium:  'medium',
-    high:    'high',
-  },
-  // 'off' maps to reasoning_effort:'none' — API confirmed to disable thinking
-  gpt5_1: {
-    off:    'none',
-    low:    'low',
+    low: 'low',
     medium: 'medium',
-    high:   'high',
-    xhigh:  null,
+    high: 'high',
+  },
+  gpt5_1: {
+    off: 'none',
+    low: 'low',
+    medium: 'medium',
+    high: 'high',
+    xhigh: null,
   },
   gpt5_2plus: {
-    off:     'none',
+    off: 'none',
     minimal: 'minimal',
-    low:     'low',
-    medium:  'medium',
-    high:    'high',
-    xhigh:   'xhigh',
+    low: 'low',
+    medium: 'medium',
+    high: 'high',
+    xhigh: 'xhigh',
   },
   grok: {
     minimal: null,
-    low:     'low',
-    medium:  null,
-    high:    'high',
-    xhigh:   null,
+    low: 'low',
+    medium: null,
+    high: 'high',
+    xhigh: null,
   },
   kimi: {
+    off: 'none',
+    auto: 'auto',
     minimal: null,
-    low:     'low',
-    medium:  'medium',
-    high:    'high',
-    xhigh:   null,
+    low: 'low',
+    medium: 'medium',
+    high: 'high',
+    xhigh: null,
   },
   doubao: {
+    off: null,
+    auto: 'auto',
+    high: 'high',
+  },
+  deepseek_hybrid: {
+    off: null,
+    auto: 'auto',
     high: 'high',
   },
 }
 
 // ── Internal: model → ThinkingType classification ─────────────────────────────
 
+/**
+ * Broad regex matching common reasoning model naming patterns.
+ * Used as a fallback when no specific provider/model rule matches.
+ * Excludes explicit '-non-reasoning' variants.
+ */
+const REASONING_FALLBACK_REGEX =
+  /^(?!.*-non-reasoning\b)(o\d+(?:-[\w-]+)?|.*\b(?:reasoning|reasoner|thinking|think)\b.*|.*-[rR]\d+.*|.*\bqwq(?:-[\w-]+)?\b.*|.*\bhunyuan-t1(?:-[\w-]+)?\b.*|.*\bgrok-(?:3-mini|4|4-fast|build)(?:-[\w-]+)?\b.*)$/i
+
 /**
  * Classify a model into a ThinkingType based on provider + model id.
- * Kept intentionally simple: providers/ids are stable enough for direct matching.
  */
 function classifyThinkingType(provider: string, modelId: string): ThinkingType {
   const id = modelId.toLowerCase()
   const prov = provider.toLowerCase()
 
-  // ── Non-reasoning paths handled by other API formats (out of scope v1) ──
-  if (prov === 'anthropic' || prov === 'gemini') return 'none'
+  // ── Explicit non-reasoning variants ──
+  if (id.includes('-non-reasoning')) return 'none'
+
+  // ── Anthropic uses different API format (out of scope) ──
+  if (prov === 'anthropic') return 'none'
+
+  // ── Gemini 2.5+ reasoning models (via Google Generative AI API) ──
+  if (prov === 'gemini') {
+    if (/gemini-(?:2\.5|3(?:\.\d+)?-(?:flash|pro)|flash-latest|pro-latest)/i.test(id)) return 'gemini'
+    return 'none'
+  }
 
   // ── Qwen (official DashScope + self-hosted models containing qwen/qwq) ──
-  if (prov === 'qwen' || /qwen|qwq/i.test(id)) return 'qwen'
+  if (prov === 'qwen' || /\bqwen|qwq/i.test(id)) return 'qwen'
 
   // ── DeepSeek V4+ ──
   if (/deepseek[_-]v([4-9]|\d{2,})/i.test(id) || /deepseek-ai\/deepseek-r1/i.test(id)) return 'deepseek_v4'
 
+  // ── DeepSeek V3.x hybrid inference (deepseek-chat, deepseek-v3.x) ──
+  if (/deepseek[_-]chat|deepseek[_-]v3/i.test(id)) return 'deepseek_hybrid'
+
   // ── OpenAI gpt-5.x family ──
   if (prov === 'openai' || prov === 'openai-compatible') {
     if (/gpt-5\.[2-9]|gpt-5\.[1-9]\d/.test(id)) return 'gpt5_2plus'
@@ -133,35 +162,57 @@ function classifyThinkingType(provider: string, modelId: string): ThinkingType {
   // o-series on other providers (e.g., Azure, OpenRouter)
   if (/^o\d/.test(id)) return 'o_series'
 
-  // ── xAI Grok reasoning models ──
-  if (prov === 'xai' && /grok-[34]/i.test(id) && /mini|4\b/i.test(id)) return 'grok'
+  // ── xAI Grok reasoning models (grok-3-mini, grok-4, grok-4-fast, grok-build) ──
+  if (/\bgrok-(?:3-mini|4|4-fast|build)\b/i.test(id)) return 'grok'
 
-  // ── Kimi thinking models ──
+  // ── Kimi thinking models (k2-thinking, k2.5+, k3+) ──
+  if (/\bkimi-k(?:2-thinking|2\.[5-9]|[3-9])/i.test(id)) return 'kimi'
   if (prov === 'kimi' && /thinking/i.test(id)) return 'kimi'
 
   // ── Doubao seed reasoning ──
-  if (prov === 'doubao' && /seed/i.test(id)) return 'doubao'
+  if (/\bdoubao-.*seed/i.test(id) || (prov === 'doubao' && /seed/i.test(id))) return 'doubao'
 
-  // ── GLM (ZAI) — only boolean enable_thinking, same as Qwen ──
-  if (prov === 'glm' || /glm[-_]/i.test(id)) return 'qwen'
+  // ── Hunyuan reasoning models ──
+  if (/\bhunyuan-(?:t1|a13b)/i.test(id)) return 'hunyuan'
+
+  // ── GLM (ZAI) — glm-5, glm-4.5/4.6/4.7, glm-z1, glm-zero-preview ──
+  if (prov === 'glm' || /\bglm-?(?:5|4\.[5-7]|z1|zero)/i.test(id)) return 'qwen'
 
   // ── SiliconFlow hosted reasoning models (DeepSeek R1 family) ──
   if (prov === 'siliconflow' && /r[1-9]/i.test(id)) return 'deepseek_v4'
 
-  // ── OpenRouter: wrap by inner model id if known ──
+  // ── OpenRouter: classify by inner model id ──
   if (prov === 'openrouter') {
     if (/deepseek.*(v[4-9]|r\d)/i.test(id)) return 'deepseek_v4'
-    return 'default'
+    if (/deepseek[_-]?(chat|v3)/i.test(id)) return 'deepseek_hybrid'
+    if (/\bgrok-(?:3-mini|4|4-fast|build)\b/i.test(id)) return 'grok'
+    if (/\bkimi-k(?:2-thinking|2\.[5-9]|[3-9])/i.test(id)) return 'kimi'
+    if (REASONING_FALLBACK_REGEX.test(id)) return 'default'
+    return 'none'
   }
 
+  // ── Models using thinking:{type:'disabled'/'enabled'} format (same as DeepSeek) ──
+  if (/\bmimo-v2/i.test(id)) return 'deepseek_hybrid'
+  if (/\bminimax-m[123]/i.test(id)) return 'deepseek_hybrid'
+  if (/\bseed-oss/i.test(id)) return 'deepseek_hybrid'
+
+  // ── Known reasoning model families → 'default' bucket (supportsReasoningEffort) ──
+  if (/\bbaichuan-m[23]/i.test(id)) return 'default'
+  if (/\bmagistral/i.test(id)) return 'default'
+  if (/\bmistral-small-2603/i.test(id)) return 'default'
+  if (/\bstep-(?:3|r1-v-mini)/i.test(id)) return 'default'
+  if (/\bgemma-?4/i.test(id)) return 'default'
+  if (/\bpangu-pro-moe/i.test(id)) return 'default'
+  if (/\bsonar-deep-research/i.test(id)) return 'default'
+  if (/\bring-(?:1t|mini|flash)/i.test(id)) return 'default'
+
   // ── Self-hosted / unknown — heuristic from model name ──
-  if (/qwen|qwq/i.test(id)) return 'qwen'
+  if (/\bqwen|qwq/i.test(id)) return 'qwen'
   if (/deepseek[_-]?r\d|deepseek[_-]?v[4-9]/i.test(id)) return 'deepseek_v4'
   if (/^o\d/i.test(id)) return 'o_series'
 
-  // Only assign 'default' (reasoning bucket) when the model name itself
-  // suggests thinking capability. Otherwise return 'none'.
-  if (/reasoning|thinking|r1\b|r2\b|qwq|think/i.test(id)) return 'default'
+  // Broad fallback: match common reasoning naming patterns
+  if (REASONING_FALLBACK_REGEX.test(id)) return 'default'
 
   return 'none'
 }
@@ -184,7 +235,6 @@ export function getSupportedThinkingLevels(provider: string, modelId: string): T
  * on the openai-completions path. (anthropic/gemini always return false here.)
  *
  * Used by: buildPiModel to set `PiModel.reasoning`.
- * Replaces the ad-hoc inferReasoning logic in llm-builder.ts.
  */
 export function isReasoningModel(provider: string, modelId: string): boolean {
   return classifyThinkingType(provider, modelId) !== 'none'
@@ -197,8 +247,8 @@ export function isReasoningModel(provider: string, modelId: string): boolean {
  * Used by: buildPiModel (openai-completions branch).
  */
 export interface ThinkingCompat {
-  thinkingFormat?: 'qwen' | 'deepseek'  // provider-specific injection format
-  supportsReasoningEffort?: true         // OpenAI-style reasoning_effort param
+  thinkingFormat?: 'qwen' | 'deepseek'
+  supportsReasoningEffort?: true
   thinkingLevelMap?: Partial<Record<ThinkingLevel, string | null>>
 }
 
@@ -207,23 +257,27 @@ export function getThinkingCompat(provider: string, modelId: string): ThinkingCo
 
   if (type === 'none') return {}
 
-  if (type === 'qwen') {
-    // Qwen/GLM: pi-ai injects enable_thinking boolean.
-    // 'off' → reasoningEffort=undefined → enable_thinking:false
-    // 'high' → reasoningEffort='high' → enable_thinking:true
+  // Gemini uses pi-ai's native Google provider; no compat fields needed.
+  if (type === 'gemini') return {}
+
+  if (type === 'qwen' || type === 'hunyuan') {
     return { thinkingFormat: 'qwen' }
   }
 
   if (type === 'deepseek_v4') {
-    // DeepSeek requires thinkingFormat:'deepseek' so pi-ai sends:
-    //   thinking:{type:"disabled"} when reasoningEffort=undefined (off)
-    //   thinking:{type:"enabled"} + reasoning_effort when set
     return {
       thinkingFormat: 'deepseek',
       thinkingLevelMap: { high: 'high', xhigh: 'max', minimal: null, low: null, medium: null },
     }
   }
 
+  if (type === 'deepseek_hybrid') {
+    return {
+      thinkingFormat: 'deepseek',
+      thinkingLevelMap: { auto: 'auto', high: 'high', minimal: null, low: null, medium: null, xhigh: null },
+    }
+  }
+
   // All remaining types use OpenAI-style reasoning_effort.
   const compat: ThinkingCompat = { supportsReasoningEffort: true }
   const levelMap = TYPE_LEVEL_MAP[type]
diff --git a/packages/node-runtime/src/ai/__tests__/llm-builder.test.ts b/packages/node-runtime/src/ai/__tests__/llm-builder.test.ts
index f5eb5061..a1b91427 100644
--- a/packages/node-runtime/src/ai/__tests__/llm-builder.test.ts
+++ b/packages/node-runtime/src/ai/__tests__/llm-builder.test.ts
@@ -153,7 +153,8 @@ describe('buildPiModel', () => {
     // Must use thinkingFormat:'deepseek' so that 'off' sends thinking:{type:"disabled"}
     assert.equal(compat?.thinkingFormat, 'deepseek')
     assert.equal(compat?.supportsReasoningEffort, undefined)
-    const map = compat?.thinkingLevelMap as Record<string, unknown> | undefined
+    // thinkingLevelMap is on the model top-level (for clampThinkingLevel)
+    const map = model.thinkingLevelMap as Record<string, unknown> | undefined
     assert.equal(map?.high, 'high')
     assert.equal(map?.xhigh, 'max')
     assert.equal(map?.minimal, null)
diff --git a/packages/node-runtime/src/ai/agent/core.ts b/packages/node-runtime/src/ai/agent/core.ts
index 64ba74db..80a8ed4a 100644
--- a/packages/node-runtime/src/ai/agent/core.ts
+++ b/packages/node-runtime/src/ai/agent/core.ts
@@ -87,15 +87,44 @@ export async function runAgentCore(options: AgentCoreOptions): Promise<AgentCore
     return { usage: totalUsage, finalMessages: [], toolsUsed: [], toolRounds: 0 }
   }
 
+  // Resolve thinkingLevel for pi-agent-core:
+  // - 'default'/undefined → strip reasoning from piModel so pi-ai sends a plain request
+  //   with NO reasoning params at all (model uses its native default behavior).
+  // - 'off' → pi-ai sends disable signals (thinking:{type:'disabled'} / enable_thinking:false)
+  // - 'auto' → for thinkingFormat models, use 'high' to enable; others no params
+  // - Other levels → clamp to what pi-agent-core accepts.
+  const isDefault = !options.thinkingLevel || options.thinkingLevel === 'default'
+  const effectiveModel = isDefault
+    ? { ...piModel, reasoning: false, compat: undefined, thinkingLevelMap: undefined }
+    : piModel
+
+  const resolvedThinkingLevel = (() => {
+    if (isDefault) return 'off'
+    const level = options.thinkingLevel!
+    if (level === 'auto') {
+      if (!piModel.reasoning) return 'off'
+      const compat = piModel.compat as Record<string, unknown> | undefined
+      if (compat?.thinkingFormat) return 'high'
+      return undefined
+    }
+    return clampThinkingLevel(piModel, level as Exclude<typeof level, 'default' | 'auto'>)
+  })()
+
+  const finalThinkingLevel = resolvedThinkingLevel ?? (piModel.reasoning ? undefined : 'off')
+  console.debug('[agent-core] thinkingLevel resolution:', {
+    input: options.thinkingLevel,
+    modelId: piModel.id,
+    modelReasoning: effectiveModel.reasoning,
+    isDefault,
+    resolved: resolvedThinkingLevel,
+    final: finalThinkingLevel,
+  })
+
   const coreAgent = new PiAgentCore({
     initialState: {
       systemPrompt,
-      model: piModel,
-      thinkingLevel: options.thinkingLevel
-        ? clampThinkingLevel(piModel, options.thinkingLevel)
-        : piModel.reasoning
-          ? 'medium'
-          : 'off',
+      model: effectiveModel,
+      thinkingLevel: finalThinkingLevel,
       tools: maxToolRounds > 0 ? tools : [],
       messages: toPiHistoryMessages(history),
     },
diff --git a/packages/node-runtime/src/ai/llm-builder.ts b/packages/node-runtime/src/ai/llm-builder.ts
index 5d27c93a..4136692b 100644
--- a/packages/node-runtime/src/ai/llm-builder.ts
+++ b/packages/node-runtime/src/ai/llm-builder.ts
@@ -79,26 +79,29 @@ const BUILTIN_PROVIDER_API: Record<string, PiApi> = {
  * carries supportsReasoningEffort + thinkingLevelMap so pi-ai can inject the
  * correct request-body param for each provider family.
  */
-function inferReasoning(
-  provider: string,
-  modelId: string,
-  modelDef: ModelDefinition | null,
-): { reasoning: boolean; compat: PiModel<PiApi>['compat'] } {
-  // Catalog capabilities are authoritative; fall back to name-heuristic for
-  // unlisted / self-hosted models.
-  const reasoning = modelDef
-    ? modelDef.capabilities.includes('reasoning')
-    : isReasoningModel(provider, modelId)
+interface InferReasoningResult {
+  reasoning: boolean
+  compat: PiModel<PiApi>['compat']
+  thinkingLevelMap?: PiModel<PiApi>['thinkingLevelMap']
+}
+
+function inferReasoning(provider: string, modelId: string, modelDef: ModelDefinition | null): InferReasoningResult {
+  const reasoning = modelDef ? modelDef.capabilities.includes('reasoning') : isReasoningModel(provider, modelId)
 
   if (!reasoning) return { reasoning: false, compat: undefined }
 
   const thinkingCompat = getThinkingCompat(provider, modelId)
-  // thinkingCompat may be an empty object {} for unknown reasoning models —
-  // that's fine: pi-ai will still receive reasoning:true and default to
-  // passing the effort level verbatim.
+  if (Object.keys(thinkingCompat).length === 0) {
+    return { reasoning: true, compat: undefined }
+  }
+
+  // thinkingLevelMap belongs on the Model top-level (for clampThinkingLevel),
+  // while thinkingFormat/supportsReasoningEffort belong in compat (for the provider).
+  const { thinkingLevelMap, ...compatFields } = thinkingCompat
   return {
     reasoning: true,
-    compat: Object.keys(thinkingCompat).length > 0 ? thinkingCompat : undefined,
+    compat: Object.keys(compatFields).length > 0 ? compatFields : undefined,
+    thinkingLevelMap: thinkingLevelMap as PiModel<PiApi>['thinkingLevelMap'],
   }
 }
 
@@ -120,7 +123,7 @@ export function buildPiModel(config: PiModelConfig, options?: BuildPiModelOption
       api: 'google-generative-ai',
       provider: 'google',
       baseUrl,
-      reasoning: false,
+      reasoning: isReasoningModel(config.provider, modelId),
       input: ['text'],
       cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
       contextWindow,
@@ -148,7 +151,7 @@ export function buildPiModel(config: PiModelConfig, options?: BuildPiModelOption
       ? normalizeOpenAICompatibleBaseUrl(baseUrl)
       : baseUrl
 
-  const { reasoning, compat } = inferReasoning(config.provider, modelId, modelDef)
+  const { reasoning, compat, thinkingLevelMap } = inferReasoning(config.provider, modelId, modelDef)
 
   return {
     id: modelId,
@@ -158,6 +161,7 @@ export function buildPiModel(config: PiModelConfig, options?: BuildPiModelOption
     baseUrl: resolvedBaseUrl,
     headers: options?.headers,
     reasoning,
+    thinkingLevelMap,
     input: ['text'],
     cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
     contextWindow,
diff --git a/src/components/AIChat/chat/ChatStatusBar.vue b/src/components/AIChat/chat/ChatStatusBar.vue
index 21e2a8a7..a32119e9 100644
--- a/src/components/AIChat/chat/ChatStatusBar.vue
+++ b/src/components/AIChat/chat/ChatStatusBar.vue
@@ -233,11 +233,11 @@ const supportedThinkingLevels = computed<ThinkingLevel[]>(() => {
 /** Whether to show the selector at all. */
 const showThinkingSelector = computed(() => supportedThinkingLevels.value.length > 0)
 
-/** The currently remembered level for this model slot (undefined → default). */
-const currentThinkingLevel = computed<ThinkingLevel | undefined>(() => {
+/** The currently remembered level for this model slot (undefined → 'default'). */
+const currentThinkingLevel = computed<ThinkingLevel>(() => {
   const cfg = llmStore.defaultAssistant
-  if (!cfg?.configId || !cfg?.modelId) return undefined
-  return promptStore.getThinkingLevel(cfg.configId, cfg.modelId)
+  if (!cfg?.configId || !cfg?.modelId) return 'default'
+  return promptStore.getThinkingLevel(cfg.configId, cfg.modelId) ?? 'default'
 })
 
 function selectThinkingLevel(level: ThinkingLevel) {
@@ -249,10 +249,7 @@ function selectThinkingLevel(level: ThinkingLevel) {
 
 /** Label shown on the trigger button. */
 const thinkingLevelLabel = computed(() => {
-  const level = currentThinkingLevel.value
-  // undefined means no explicit preference set — core defaults to 'medium'
-  if (level === undefined) return t('ai.chat.statusBar.thinking.auto')
-  return t(`ai.chat.statusBar.thinking.level.${level}`)
+  return t(`ai.chat.statusBar.thinking.level.${currentThinkingLevel.value}`)
 })
 </script>
 
@@ -332,9 +329,9 @@ const thinkingLevelLabel = computed(() => {
         <button
           class="flex items-center gap-1.5 rounded-md px-2 py-1 text-xs transition-colors hover:bg-gray-100 dark:hover:bg-gray-800"
           :class="
-            !currentThinkingLevel || currentThinkingLevel === 'off'
+            currentThinkingLevel === 'default' || currentThinkingLevel === 'off'
               ? 'text-gray-400 dark:text-gray-500'
-              : 'text-blue-500 dark:text-blue-400'
+              : 'text-primary-500 dark:text-primary-400'
           "
           :title="t('ai.chat.statusBar.thinking.tooltip')"
         >
@@ -351,20 +348,16 @@ const thinkingLevelLabel = computed(() => {
               :key="level"
               class="flex w-full items-center gap-2 px-3 py-2 text-left text-sm transition-colors hover:bg-gray-100 dark:hover:bg-gray-800"
               :class="
-                (currentThinkingLevel ?? 'medium') === level
-                  ? 'text-blue-600 dark:text-blue-400'
+                currentThinkingLevel === level
+                  ? 'text-primary-600 dark:text-primary-400'
                   : 'text-gray-700 dark:text-gray-300'
               "
               @click="selectThinkingLevel(level)"
             >
               <UIcon
-                :name="
-                  (currentThinkingLevel ?? 'medium') === level
-                    ? 'i-heroicons-check-circle-solid'
-                    : 'i-heroicons-light-bulb'
-                "
+                :name="currentThinkingLevel === level ? 'i-heroicons-check-circle-solid' : 'i-heroicons-light-bulb'"
                 class="h-4 w-4 shrink-0"
-                :class="(currentThinkingLevel ?? 'medium') === level ? 'text-blue-500' : 'text-gray-400'"
+                :class="currentThinkingLevel === level ? 'text-primary-500' : 'text-gray-400'"
               />
               <span>{{ t(`ai.chat.statusBar.thinking.level.${level}`) }}</span>
             </button>
diff --git a/src/i18n/locales/en-US/ai.json b/src/i18n/locales/en-US/ai.json
index b94ddb2b..d08c2b38 100644
--- a/src/i18n/locales/en-US/ai.json
+++ b/src/i18n/locales/en-US/ai.json
@@ -181,15 +181,15 @@
       "thinking": {
         "title": "Thinking level",
         "tooltip": "Set the thinking intensity for this model",
-        "auto": "Auto",
-        "off": "Thinking off",
         "level": {
+          "default": "Default",
           "off": "Off",
           "minimal": "Minimal",
           "low": "Low",
           "medium": "Medium",
           "high": "High",
-          "xhigh": "Max"
+          "xhigh": "Max",
+          "auto": "Auto"
         }
       },
       "tokenUsageTitle": "Total token usage",
@@ -517,4 +517,4 @@
       "truncated": "Result too large, truncated. Try reducing the limit parameter for complete data."
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src/i18n/locales/ja-JP/ai.json b/src/i18n/locales/ja-JP/ai.json
index 11b77ec2..ade4ae01 100644
--- a/src/i18n/locales/ja-JP/ai.json
+++ b/src/i18n/locales/ja-JP/ai.json
@@ -181,15 +181,15 @@
       "thinking": {
         "title": "思考強度",
         "tooltip": "モデルの思考強度を設定",
-        "auto": "自動",
-        "off": "思考オフ",
         "level": {
+          "default": "デフォルト",
           "off": "オフ",
           "minimal": "極小",
           "low": "低",
           "medium": "中",
           "high": "高",
-          "xhigh": "最大"
+          "xhigh": "最大",
+          "auto": "自動"
         }
       },
       "tokenUsageTitle": "累計 Token 使用量",
@@ -481,4 +481,4 @@
       "truncated": "結果が大きすぎるため、切り捨てて表示しています。limit パラメータを小さくしてください。"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src/i18n/locales/zh-CN/ai.json b/src/i18n/locales/zh-CN/ai.json
index d0b42144..cd3d578c 100644
--- a/src/i18n/locales/zh-CN/ai.json
+++ b/src/i18n/locales/zh-CN/ai.json
@@ -181,15 +181,15 @@
       "thinking": {
         "title": "思考强度",
         "tooltip": "设置模型的思考强度",
-        "auto": "自动",
-        "off": "关闭思考",
         "level": {
-          "off": "关闭思考",
+          "default": "默认",
+          "off": "关闭",
           "minimal": "极低",
           "low": "低",
           "medium": "中",
           "high": "高",
-          "xhigh": "最高"
+          "xhigh": "最高",
+          "auto": "自动"
         }
       },
       "tokenUsageTitle": "累计 Token 使用量",
diff --git a/src/i18n/locales/zh-TW/ai.json b/src/i18n/locales/zh-TW/ai.json
index 7f7a195a..eb0315fc 100644
--- a/src/i18n/locales/zh-TW/ai.json
+++ b/src/i18n/locales/zh-TW/ai.json
@@ -181,15 +181,15 @@
       "thinking": {
         "title": "思考強度",
         "tooltip": "設定模型的思考強度",
-        "auto": "自動",
-        "off": "關閉思考",
         "level": {
-          "off": "關閉思考",
+          "default": "預設",
+          "off": "關閉",
           "minimal": "極低",
           "low": "低",
           "medium": "中",
           "high": "高",
-          "xhigh": "最高"
+          "xhigh": "最高",
+          "auto": "自動"
         }
       },
       "tokenUsageTitle": "累計 Token 用量",
@@ -481,4 +481,4 @@
       "truncated": "結果過大，已截斷顯示。建議減小 limit 參數以獲取完整資料。"
     }
   }
-}
\ No newline at end of file
+}