fix(chat): reset model override with default

CHANGELOG.md

@@ -154,6 +154,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Chat commands: make `/model default` reset the session model override instead of treating it as a literal model name. Fixes #78182.
 - Cron: make rejected `payload.model` errors show the configured `agents.defaults.models` allowlist instead of echoing the rejected model twice. Fixes #79058.
 - Agents/subagents: retry parent wake announces when the announce-summary model run fails with fallback cooldown exhaustion instead of dropping the wake on the first transient provider overload. Refs #78581.
 - Providers/network: honor IPv4 CIDR and octet-wildcard `NO_PROXY` entries such as `100.64.0.0/10` and `100.64.*` before enabling trusted env-proxy mode for model-provider requests. Fixes #79030.

src/auto-reply/reply/directive-handling.model-selection.ts

@@ -66,6 +66,15 @@ export function resolveModelSelectionFromDirective(params: {
   }
 
   const raw = params.directives.rawModelDirective.trim();
+  if (/^default$/i.test(raw)) {
+    return {
+      modelSelection: {
+        provider: params.defaultProvider,
+        model: params.defaultModel,
+        isDefault: true,
+      },
+    };
+  }
   const storedNumericProfile =
     params.directives.rawModelProfile === undefined
       ? resolveStoredNumericProfileModelDirective({

src/auto-reply/reply/directive-handling.model.test.ts

@@ -643,6 +643,21 @@ describe("/model chat UX", () => {
     });
   });
 
+  it("treats /model default as a session model reset", () => {
+    const resolved = resolveModelSelectionForCommand({
+      command: "/model default",
+      allowedModelKeys: new Set(["anthropic/claude-opus-4-6", "openai/gpt-4o"]),
+      allowedModelCatalog: [],
+    });
+
+    expect(resolved.errorText).toBeUndefined();
+    expect(resolved.modelSelection).toEqual({
+      provider: "anthropic",
+      model: "claude-opus-4-6",
+      isDefault: true,
+    });
+  });
+
   it("keeps openrouter provider/model split for exact selections", () => {
     const resolved = resolveModelSelectionForCommand({
       command: "/model openrouter/anthropic/claude-opus-4-6",