refactor(agent): centralize fallback run helpers

src/agents/agent-scope.e2e.test.ts

@@ -4,6 +4,7 @@ import type { OpenClawConfig } from "../config/config.js";
 import {
   resolveAgentConfig,
   resolveAgentDir,
+  resolveEffectiveModelFallbacks,
   resolveAgentModelFallbacksOverride,
   resolveAgentModelPrimary,
   resolveAgentWorkspaceDir,
@@ -112,6 +113,60 @@ describe("resolveAgentConfig", () => {
       },
     };
     expect(resolveAgentModelFallbacksOverride(cfgDisable, "linus")).toEqual([]);
+
+    expect(
+      resolveEffectiveModelFallbacks({
+        cfg,
+        agentId: "linus",
+        hasSessionModelOverride: false,
+      }),
+    ).toEqual(["openai/gpt-5.2"]);
+    expect(
+      resolveEffectiveModelFallbacks({
+        cfg,
+        agentId: "linus",
+        hasSessionModelOverride: true,
+      }),
+    ).toEqual(["openai/gpt-5.2"]);
+    expect(
+      resolveEffectiveModelFallbacks({
+        cfg: cfgNoOverride,
+        agentId: "linus",
+        hasSessionModelOverride: true,
+      }),
+    ).toEqual([]);
+
+    const cfgInheritDefaults: OpenClawConfig = {
+      agents: {
+        defaults: {
+          model: {
+            fallbacks: ["openai/gpt-4.1"],
+          },
+        },
+        list: [
+          {
+            id: "linus",
+            model: {
+              primary: "anthropic/claude-opus-4",
+            },
+          },
+        ],
+      },
+    };
+    expect(
+      resolveEffectiveModelFallbacks({
+        cfg: cfgInheritDefaults,
+        agentId: "linus",
+        hasSessionModelOverride: true,
+      }),
+    ).toEqual(["openai/gpt-4.1"]);
+    expect(
+      resolveEffectiveModelFallbacks({
+        cfg: cfgDisable,
+        agentId: "linus",
+        hasSessionModelOverride: true,
+      }),
+    ).toEqual([]);
   });
 
   it("should return agent-specific sandbox config", () => {

src/agents/agent-scope.ts

@@ -163,6 +163,22 @@ export function resolveAgentModelFallbacksOverride(
   return Array.isArray(raw.fallbacks) ? raw.fallbacks : undefined;
 }
 
+export function resolveEffectiveModelFallbacks(params: {
+  cfg: OpenClawConfig;
+  agentId: string;
+  hasSessionModelOverride: boolean;
+}): string[] | undefined {
+  const agentFallbacksOverride = resolveAgentModelFallbacksOverride(params.cfg, params.agentId);
+  if (!params.hasSessionModelOverride) {
+    return agentFallbacksOverride;
+  }
+  const defaultFallbacks =
+    typeof params.cfg.agents?.defaults?.model === "object"
+      ? (params.cfg.agents.defaults.model.fallbacks ?? [])
+      : [];
+  return agentFallbacksOverride ?? defaultFallbacks;
+}
+
 export function resolveAgentWorkspaceDir(cfg: OpenClawConfig, agentId: string) {
   const id = normalizeAgentId(agentId);
   const configured = resolveAgentConfig(cfg, id)?.workspace?.trim();