fix: respect session model override in agent runtime (#14783) (#14983)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: ec47d1a7bf
Co-authored-by: shtse8 <8020099+shtse8@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

src/auto-reply/reply/model-selection.override-respected.test.ts

@@ -0,0 +1,132 @@
+import { describe, expect, it, vi } from "vitest";
+import type { OpenClawConfig } from "../../config/config.js";
+import { createModelSelectionState } from "./model-selection.js";
+
+vi.mock("../../agents/model-catalog.js", () => ({
+  loadModelCatalog: vi.fn(async () => [
+    { provider: "inferencer", id: "deepseek-v3-4bit-mlx", name: "DeepSeek V3" },
+    { provider: "kimi-coding", id: "k2p5", name: "Kimi K2.5" },
+    { provider: "anthropic", id: "claude-opus-4-5", name: "Claude Opus 4.5" },
+  ]),
+}));
+
+const defaultProvider = "inferencer";
+const defaultModel = "deepseek-v3-4bit-mlx";
+
+const makeEntry = (overrides: Record<string, unknown> = {}) => ({
+  sessionId: "session-id",
+  updatedAt: Date.now(),
+  ...overrides,
+});
+
+describe("createModelSelectionState respects session model override", () => {
+  it("applies session modelOverride when set", async () => {
+    const cfg = {} as OpenClawConfig;
+    const sessionKey = "agent:main:main";
+    const sessionEntry = makeEntry({
+      providerOverride: "kimi-coding",
+      modelOverride: "k2p5",
+    });
+    const sessionStore = { [sessionKey]: sessionEntry };
+
+    const state = await createModelSelectionState({
+      cfg,
+      agentCfg: undefined,
+      sessionEntry,
+      sessionStore,
+      sessionKey,
+      defaultProvider,
+      defaultModel,
+      provider: defaultProvider,
+      model: defaultModel,
+      hasModelDirective: false,
+    });
+
+    expect(state.provider).toBe("kimi-coding");
+    expect(state.model).toBe("k2p5");
+  });
+
+  it("falls back to default when no modelOverride is set", async () => {
+    const cfg = {} as OpenClawConfig;
+    const sessionKey = "agent:main:main";
+    const sessionEntry = makeEntry();
+    const sessionStore = { [sessionKey]: sessionEntry };
+
+    const state = await createModelSelectionState({
+      cfg,
+      agentCfg: undefined,
+      sessionEntry,
+      sessionStore,
+      sessionKey,
+      defaultProvider,
+      defaultModel,
+      provider: defaultProvider,
+      model: defaultModel,
+      hasModelDirective: false,
+    });
+
+    expect(state.provider).toBe(defaultProvider);
+    expect(state.model).toBe(defaultModel);
+  });
+
+  it("respects modelOverride even when session model field differs", async () => {
+    // This tests the scenario from issue #14783: user switches model via /model,
+    // the override is stored, but session.model still reflects the last-used
+    // fallback model. The override should take precedence.
+    const cfg = {} as OpenClawConfig;
+    const sessionKey = "agent:main:main";
+    const sessionEntry = makeEntry({
+      // Last-used model (from fallback) - should NOT be used for selection
+      model: "k2p5",
+      modelProvider: "kimi-coding",
+      contextTokens: 262_000,
+      // User's explicit override - SHOULD be used
+      providerOverride: "anthropic",
+      modelOverride: "claude-opus-4-5",
+    });
+    const sessionStore = { [sessionKey]: sessionEntry };
+
+    const state = await createModelSelectionState({
+      cfg,
+      agentCfg: undefined,
+      sessionEntry,
+      sessionStore,
+      sessionKey,
+      defaultProvider,
+      defaultModel,
+      provider: defaultProvider,
+      model: defaultModel,
+      hasModelDirective: false,
+    });
+
+    // Should use the override, not the last-used model
+    expect(state.provider).toBe("anthropic");
+    expect(state.model).toBe("claude-opus-4-5");
+  });
+
+  it("uses default provider when providerOverride is not set but modelOverride is", async () => {
+    const cfg = {} as OpenClawConfig;
+    const sessionKey = "agent:main:main";
+    const sessionEntry = makeEntry({
+      modelOverride: "deepseek-v3-4bit-mlx",
+      // no providerOverride
+    });
+    const sessionStore = { [sessionKey]: sessionEntry };
+
+    const state = await createModelSelectionState({
+      cfg,
+      agentCfg: undefined,
+      sessionEntry,
+      sessionStore,
+      sessionKey,
+      defaultProvider,
+      defaultModel,
+      provider: defaultProvider,
+      model: defaultModel,
+      hasModelDirective: false,
+    });
+
+    expect(state.provider).toBe(defaultProvider);
+    expect(state.model).toBe("deepseek-v3-4bit-mlx");
+  });
+});