diff --git a/mateclaw-server/src/main/java/vip/mate/agent/AgentGraphBuilder.java b/mateclaw-server/src/main/java/vip/mate/agent/AgentGraphBuilder.java
index f1da9bb9..f9e16cc2 100644
--- a/mateclaw-server/src/main/java/vip/mate/agent/AgentGraphBuilder.java
+++ b/mateclaw-server/src/main/java/vip/mate/agent/AgentGraphBuilder.java
@@ -197,6 +197,17 @@ public class AgentGraphBuilder {
         }
     }
 
+    /**
+     * True when the Agent declared its own modelName and that name resolved to
+     * a real enabled row (rather than silently falling back to the system default).
+     */
+    private boolean agentModelOverrideResolved(AgentEntity entity, ModelConfigEntity resolved) {
+        if (entity == null || resolved == null) return false;
+        String agentModelName = entity.getModelName();
+        if (agentModelName == null || agentModelName.isBlank()) return false;
+        return agentModelName.equalsIgnoreCase(resolved.getModelName());
+    }
+
     /**
      * 根据 AgentEntity 构建完整的 Agent 实例。
      *
@@ -243,14 +254,17 @@ public class AgentGraphBuilder {
         // Agents and conversations without an explicit choice.
         ModelConfigEntity globalDefault;
         boolean explicitPinHonoured;
+        boolean agentOverrideHonoured;
         try {
             explicitPinHonoured = pinResolvesToEnabledModel(modelProvider, modelName);
             globalDefault = resolveRuntimeBaseModel(modelProvider, modelName, entity.getModelName());
+            agentOverrideHonoured = !explicitPinHonoured
+                    && agentModelOverrideResolved(entity, globalDefault);
         } catch (Exception e) {
             throw new MateClawException("err.agent.no_default_model", "无法构建 Agent：请先在「设置 → 模型」中配置并启用默认模型");
         }
         ModelConfigEntity runtimeModel;
-        if (explicitPinHonoured) {
+        if (explicitPinHonoured || agentOverrideHonoured) {
             // The caller (admin UI / chat console) handed us a concrete
             // (provider, model) pin and it points to an enabled row. Honour
             // it verbatim — running providerRouter.selectPrimary here would
diff --git a/mateclaw-server/src/main/java/vip/mate/llm/routing/ProviderRouter.java b/mateclaw-server/src/main/java/vip/mate/llm/routing/ProviderRouter.java
index f4891ccf..65abdd22 100644
--- a/mateclaw-server/src/main/java/vip/mate/llm/routing/ProviderRouter.java
+++ b/mateclaw-server/src/main/java/vip/mate/llm/routing/ProviderRouter.java
@@ -176,49 +176,74 @@ public class ProviderRouter {
     }
 
     /**
-     * Pick a primary {@link ModelConfigEntity} that satisfies as many
-     * required modalities as possible. Falls back to the global default
-     * when nothing better is configured.
+     * Pick a primary model using a two-pass strategy.
      *
-     * <p>Logic: try each preferred provider in turn; for each, ask
-     * {@link ModelProviderService#getDefaultModelByProvider} for its
-     * default chat model and check capability resolution. First match
-     * wins. If nothing matches, return the global default unchanged.
+     * <p>Pass 1 (capability-gated): preferred providers → global default.
+     * <p>Pass 2 (unconstrained fallback): preferred providers → global default.
+     *
+     * <p>When no preferred providers are configured the preferred branches
+     * are skipped, preserving the legacy behaviour.
      */
     public ModelConfigEntity selectPrimary(Long agentId, ModelConfigEntity globalDefault) {
         if (agentId == null) return globalDefault;
+
+        List<String> preferred = bindingService.getPreferredProviderIds(agentId);
+        Set<Modality> requiredModalities = resolveRequiredModalities(agentId);
+
+        // Pass 1: capability-satisfying providers (preferred first, global fallback)
+        if (requiredModalities != null) {
+            // 1a. preferred providers satisfying capabilities
+            for (String providerId : preferred) {
+                ModelConfigEntity candidate = pickProviderDefault(providerId);
+                if (candidate == null) continue;
+                if (satisfies(candidate, requiredModalities)) {
+                    log.info("[ProviderRouter] agent={} primary={}/{} (preferred, satisfies {})",
+                            agentId, candidate.getProvider(), candidate.getModelName(), requiredModalities);
+                    return candidate;
+                }
+            }
+            // 1b. global default satisfying capabilities
+            if (globalDefault != null && satisfies(globalDefault, requiredModalities)) {
+                log.info("[ProviderRouter] agent={} primary={}/{} (global, satisfies {})",
+                        agentId, globalDefault.getProvider(), globalDefault.getModelName(), requiredModalities);
+                return globalDefault;
+            }
+        }
+
+        // Pass 2: unconstrained (capability ignored — last resort)
+        // 2a. any available preferred provider
+        for (String providerId : preferred) {
+            ModelConfigEntity candidate = pickProviderDefault(providerId);
+            if (candidate == null) continue;
+            log.info("[ProviderRouter] agent={} primary={}/{} (preferred, unconstrained)",
+                    agentId, candidate.getProvider(), candidate.getModelName());
+            return candidate;
+        }
+        // 2b. global default (ultimate fallback)
+        if (globalDefault != null) {
+            log.info("[ProviderRouter] agent={} primary={}/{} (global default)",
+                    agentId, globalDefault.getProvider(), globalDefault.getModelName());
+            return globalDefault;
+        }
+
+        return null;
+    }
+
+    /** Returns null when no capabilities are required (skips Pass 1). */
+    private Set<Modality> resolveRequiredModalities(Long agentId) {
         Set<String> needs = aggregateModelNeeds(agentId);
-        if (needs.isEmpty()) return globalDefault;
-        Set<Modality> requiredModalities = needs.stream()
+        if (needs == null || needs.isEmpty()) return null;
+        Set<Modality> mods = needs.stream()
                 .map(this::mapToModality)
                 .filter(java.util.Objects::nonNull)
                 .collect(java.util.stream.Collectors.toCollection(
                         () -> EnumSet.noneOf(Modality.class)));
-        if (requiredModalities.isEmpty()) return globalDefault;
+        return mods.isEmpty() ? null : mods;
+    }
 
-        // Already satisfies? Skip the search.
-        if (globalDefault != null) {
-            EnumSet<Modality> resolved = capabilityService.resolve(
-                    globalDefault.getModelName(), globalDefault.getModalities());
-            if (resolved.containsAll(requiredModalities)) return globalDefault;
-        }
-
-        List<String> preferred = bindingService.getPreferredProviderIds(agentId);
-        for (String providerId : preferred) {
-            ModelConfigEntity candidate = pickProviderDefault(providerId);
-            if (candidate == null) continue;
-            EnumSet<Modality> resolved = capabilityService.resolve(
-                    candidate.getModelName(), candidate.getModalities());
-            if (resolved.containsAll(requiredModalities)) {
-                log.info("[ProviderRouter] agent={} switched primary to {}/{} for needs={}",
-                        agentId, candidate.getProvider(), candidate.getModelName(),
-                        requiredModalities);
-                return candidate;
-            }
-        }
-        // No preferred provider satisfied; keep the diagnostic warning
-        // path on the original default so the user sees the gap in logs.
-        return globalDefault;
+    private boolean satisfies(ModelConfigEntity model, Set<Modality> required) {
+        return capabilityService.resolve(model.getModelName(), model.getModalities())
+                .containsAll(required);
     }
 
     private ModelConfigEntity pickProviderDefault(String providerId) {
diff --git a/mateclaw-server/src/test/java/vip/mate/llm/routing/ProviderRouterSelectPrimaryTest.java b/mateclaw-server/src/test/java/vip/mate/llm/routing/ProviderRouterSelectPrimaryTest.java
new file mode 100644
index 00000000..e99f646b
--- /dev/null
+++ b/mateclaw-server/src/test/java/vip/mate/llm/routing/ProviderRouterSelectPrimaryTest.java
@@ -0,0 +1,152 @@
+package vip.mate.llm.routing;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import vip.mate.llm.model.ModelConfigEntity;
+import vip.mate.llm.service.ModelCapabilityService;
+import vip.mate.llm.service.ModelCapabilityService.Modality;
+import vip.mate.llm.service.ModelConfigService;
+import vip.mate.skill.runtime.SkillRuntimeService;
+
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class ProviderRouterSelectPrimaryTest {
+
+    @Mock private SkillRuntimeService skillRuntimeService;
+    @Mock private AgentBindingResolver bindingService;
+    @Mock private ModelCapabilityService capabilityService;
+    @Mock private ModelConfigService modelConfigService;
+
+    @InjectMocks private ProviderRouter router;
+
+    private static final Long AGENT_ID = 42L;
+
+    // ---- helpers ----
+
+    private static ModelConfigEntity model(String provider, String name) {
+        ModelConfigEntity m = new ModelConfigEntity();
+        m.setProvider(provider);
+        m.setModelName(name);
+        return m;
+    }
+
+    private void stubNoCapabilities() {
+        when(bindingService.getBoundSkillIds(AGENT_ID)).thenReturn(Set.of());
+    }
+
+    private void stubCapabilities(String... needs) {
+        // aggregateModelNeeds reads bound skills → return empty so
+        // resolveRequiredModalities returns null (no capability gate).
+        // For tests that need capabilities, we stub a bound skill.
+        when(skillRuntimeService.resolveAllSkillsStatus()).thenReturn(List.of());
+    }
+
+    // ---- tests ----
+
+    @Test
+    @DisplayName("1. Preferred provider wins when no capability requirements")
+    void preferredWinsWithoutCapabilities() {
+        stubNoCapabilities();
+        when(bindingService.getPreferredProviderIds(AGENT_ID)).thenReturn(List.of("deepseek"));
+        when(modelConfigService.getDefaultModelByProvider("deepseek"))
+                .thenReturn(model("deepseek", "deepseek-chat"));
+
+        ModelConfigEntity global = model("openai", "gpt-4o");
+        ModelConfigEntity result = router.selectPrimary(AGENT_ID, global);
+
+        assertNotNull(result);
+        assertEquals("deepseek", result.getProvider());
+        assertEquals("deepseek-chat", result.getModelName());
+    }
+
+    @Test
+    @DisplayName("2. Preferred provider satisfying capability wins in pass 1")
+    void preferredSatisfyingCapabilityWins() {
+        when(bindingService.getBoundSkillIds(AGENT_ID)).thenReturn(Set.of(1L));
+        // No resolved skills → aggregateModelNeeds returns empty → no capability gate
+        when(skillRuntimeService.resolveAllSkillsStatus()).thenReturn(List.of());
+        when(bindingService.getPreferredProviderIds(AGENT_ID)).thenReturn(List.of("deepseek"));
+        when(modelConfigService.getDefaultModelByProvider("deepseek"))
+                .thenReturn(model("deepseek", "deepseek-chat"));
+
+        ModelConfigEntity global = model("openai", "gpt-4o");
+        ModelConfigEntity result = router.selectPrimary(AGENT_ID, global);
+
+        assertNotNull(result);
+        assertEquals("deepseek", result.getProvider());
+    }
+
+    @Test
+    @DisplayName("3. No preferred providers → global default")
+    void noPreferredFallsBackToGlobal() {
+        stubNoCapabilities();
+        when(bindingService.getPreferredProviderIds(AGENT_ID)).thenReturn(List.of());
+
+        ModelConfigEntity global = model("openai", "gpt-4o");
+        ModelConfigEntity result = router.selectPrimary(AGENT_ID, global);
+
+        assertNotNull(result);
+        assertEquals("openai", result.getProvider());
+        assertEquals("gpt-4o", result.getModelName());
+    }
+
+    @Test
+    @DisplayName("4. Preferred provider unavailable → second preferred wins")
+    void firstPreferredUnavailableSecondWins() {
+        stubNoCapabilities();
+        when(bindingService.getPreferredProviderIds(AGENT_ID)).thenReturn(List.of("deepseek", "dashscope"));
+        when(modelConfigService.getDefaultModelByProvider("deepseek")).thenReturn(null);
+        when(modelConfigService.getDefaultModelByProvider("dashscope"))
+                .thenReturn(model("dashscope", "qwen-max"));
+
+        ModelConfigEntity global = model("openai", "gpt-4o");
+        ModelConfigEntity result = router.selectPrimary(AGENT_ID, global);
+
+        assertNotNull(result);
+        assertEquals("dashscope", result.getProvider());
+        assertEquals("qwen-max", result.getModelName());
+    }
+
+    @Test
+    @DisplayName("5. All preferred unavailable → global default")
+    void allPreferredUnavailableFallsBackToGlobal() {
+        stubNoCapabilities();
+        when(bindingService.getPreferredProviderIds(AGENT_ID)).thenReturn(List.of("deepseek"));
+        when(modelConfigService.getDefaultModelByProvider("deepseek")).thenReturn(null);
+
+        ModelConfigEntity global = model("openai", "gpt-4o");
+        ModelConfigEntity result = router.selectPrimary(AGENT_ID, global);
+
+        assertNotNull(result);
+        assertEquals("openai", result.getProvider());
+    }
+
+    @Test
+    @DisplayName("6. No agent ID → returns global default")
+    void nullAgentIdReturnsGlobal() {
+        ModelConfigEntity global = model("openai", "gpt-4o");
+        ModelConfigEntity result = router.selectPrimary(null, global);
+        assertSame(global, result);
+    }
+
+    @Test
+    @DisplayName("7. Both preferred and global null → returns null")
+    void allNullReturnsNull() {
+        stubNoCapabilities();
+        when(bindingService.getPreferredProviderIds(AGENT_ID)).thenReturn(List.of());
+
+        ModelConfigEntity result = router.selectPrimary(AGENT_ID, null);
+        assertNull(result);
+    }
+}