diff --git a/src/lib/agent-settings.ts b/src/lib/agent-settings.ts
new file mode 100644
index 0000000..d480785
--- /dev/null
+++ b/src/lib/agent-settings.ts
@@ -0,0 +1,88 @@
+import type { AgentSettings } from "../types";
+
+const DEFAULT_SETTINGS: AgentSettings = {
+  thinking: {
+    enabled: true,
+    effort: "medium",
+    keep: "all",
+  },
+  loop_control: {
+    max_retries_per_step: 3,
+    reserved_context_size: 50000,
+  },
+  background: {
+    keep_alive_on_exit: false,
+  },
+  permission: { rules: [] },
+  hooks: [],
+};
+
+function asRecord(value: unknown): Record<string, unknown> {
+  if (value && typeof value === "object" && !Array.isArray(value)) {
+    return value as Record<string, unknown>;
+  }
+  return {};
+}
+
+function getSection<T>(rawOther: unknown, key: string): T | undefined {
+  const root = asRecord(rawOther);
+  const section = root[key];
+  if (section === undefined || section === null) return undefined;
+  return section as T;
+}
+
+export function getAgentSettings(rawOther: unknown): AgentSettings {
+  return {
+    thinking: {
+      ...DEFAULT_SETTINGS.thinking,
+      ...getSection<AgentSettings["thinking"]>(rawOther, "thinking"),
+    },
+    loop_control: {
+      ...DEFAULT_SETTINGS.loop_control,
+      ...getSection<AgentSettings["loop_control"]>(rawOther, "loop_control"),
+    },
+    background: {
+      ...DEFAULT_SETTINGS.background,
+      ...getSection<AgentSettings["background"]>(rawOther, "background"),
+    },
+    permission: {
+      rules:
+        getSection<AgentSettings["permission"]>(rawOther, "permission")?.rules ??
+        [],
+    },
+    hooks: getSection<AgentSettings["hooks"]>(rawOther, "hooks") ?? [],
+  };
+}
+
+export function setAgentSettings(
+  rawOther: unknown,
+  patch: Partial<AgentSettings>
+): unknown {
+  const root = { ...asRecord(rawOther) };
+  const current = getAgentSettings(rawOther);
+  const next: AgentSettings = {
+    thinking: { ...current.thinking, ...patch.thinking },
+    loop_control: { ...current.loop_control, ...patch.loop_control },
+    background: { ...current.background, ...patch.background },
+    permission: {
+      rules: patch.permission?.rules ?? current.permission?.rules ?? [],
+    },
+    hooks: patch.hooks ?? current.hooks ?? [],
+  };
+
+  if (next.thinking) root.thinking = next.thinking;
+  if (next.loop_control) root.loop_control = next.loop_control;
+  if (next.background) root.background = next.background;
+  if (next.permission?.rules && next.permission.rules.length > 0) {
+    root.permission = next.permission;
+  } else {
+    delete root.permission;
+  }
+  if (next.hooks && next.hooks.length > 0) {
+    root.hooks = next.hooks;
+  } else {
+    delete root.hooks;
+  }
+
+  return root;
+}