diff --git a/.changeset/brave-aliens-study.md b/.changeset/brave-aliens-study.md
new file mode 100644
index 00000000..cf03f8f8
--- /dev/null
+++ b/.changeset/brave-aliens-study.md
@@ -0,0 +1,5 @@
+---
+'@openai/agents-realtime': patch
+---
+
+fix: #639 Type issue with realtime agent handoffs
diff --git a/packages/agents-realtime/src/realtimeAgent.ts b/packages/agents-realtime/src/realtimeAgent.ts
index e170e6b6..82a58187 100644
--- a/packages/agents-realtime/src/realtimeAgent.ts
+++ b/packages/agents-realtime/src/realtimeAgent.ts
@@ -9,7 +9,7 @@ import { RealtimeContextData } from './realtimeSession';
 
 export type RealtimeAgentConfiguration<TContext = UnknownContext> = Partial<
   Omit<
-    AgentConfiguration<TContext, TextOutput>,
+    AgentConfiguration<RealtimeContextData<TContext>, TextOutput>,
     | 'model'
     | 'handoffs'
     | 'modelSettings'
@@ -29,7 +29,10 @@ export type RealtimeAgentConfiguration<TContext = UnknownContext> = Partial<
   /**
    * Any other `RealtimeAgent` instances the agent is able to hand off to.
    */
-  handoffs?: (RealtimeAgent | Handoff)[];
+  handoffs?: (
+    | RealtimeAgent<TContext>
+    | Handoff<RealtimeContextData<TContext>, TextOutput>
+  )[];
   /**
    * The voice intended to be used by the agent. If another agent already spoke during the
    * RealtimeSession, changing the voice during a handoff will fail.
diff --git a/packages/agents-realtime/test/realtimeAgentHandoffs.test.ts b/packages/agents-realtime/test/realtimeAgentHandoffs.test.ts
new file mode 100644
index 00000000..b3f40a80
--- /dev/null
+++ b/packages/agents-realtime/test/realtimeAgentHandoffs.test.ts
@@ -0,0 +1,107 @@
+import { describe, expect, it } from 'vitest';
+import { z } from 'zod';
+import {
+  RealtimeAgent,
+  tool,
+  RealtimeContextData,
+  type RealtimeAgentConfiguration,
+} from '../src';
+
+describe('RealtimeAgent handoffs', () => {
+  it('accepts handoffs sharing the session context', () => {
+    type SessionContext = { userId: string };
+
+    const specialist = new RealtimeAgent<SessionContext>({
+      name: 'specialist',
+    });
+
+    const mainAgent = new RealtimeAgent<SessionContext>({
+      name: 'main',
+      handoffs: [specialist],
+    });
+
+    expect(mainAgent.handoffs).toEqual([specialist]);
+  });
+
+  it('accepts handoffs with default context parameters', () => {
+    const specialist = new RealtimeAgent({
+      name: 'specialist',
+    });
+
+    const mainAgent = new RealtimeAgent({
+      name: 'main',
+      handoffs: [specialist],
+    });
+
+    expect(mainAgent.handoffs).toEqual([specialist]);
+  });
+
+  it('supports tool definitions without RealtimeContextData', () => {
+    type SessionContext = { userId: string };
+    const parameters = z.object({ message: z.string() });
+    const echoTool = tool<typeof parameters, SessionContext>({
+      name: 'echo',
+      description: 'Echo the user id with the provided message.',
+      parameters,
+      execute: async ({ message }, runContext) => {
+        // if you want to access history data, the type parameter must be RealtimeContextData<SessionContext>
+        // console.log(runContext?.context?.history);
+        return `${runContext?.context?.userId}: ${message}`;
+      },
+    });
+
+    const agent = new RealtimeAgent<SessionContext>({
+      name: 'Tool Agent',
+      tools: [echoTool],
+    });
+    expect(agent.tools).toContain(echoTool);
+  });
+
+  it('supports tool definitions that rely on RealtimeContextData', () => {
+    type SessionContext = { userId: string };
+    const parameters = z.object({ message: z.string() });
+    const echoTool = tool<
+      typeof parameters,
+      RealtimeContextData<SessionContext>
+    >({
+      name: 'echo',
+      description: 'Echo the user id with the provided message.',
+      parameters,
+      execute: async ({ message }, runContext) => {
+        // if you want to access history data, the type parameter must be RealtimeContextData<SessionContext>
+        console.log(runContext?.context?.history);
+        return `${runContext?.context?.userId}: ${message}`;
+      },
+    });
+
+    const agent = new RealtimeAgent<SessionContext>({
+      name: 'Tool Agent',
+      tools: [echoTool],
+    });
+    expect(agent.tools).toContain(echoTool);
+  });
+
+  it('rejects handoffs with incompatible session contexts', () => {
+    type SessionContext = { userId: string };
+    type OtherContext = { language: string };
+
+    const specialist = new RealtimeAgent<SessionContext>({
+      name: 'specialist',
+    });
+
+    const validConfig: RealtimeAgentConfiguration<SessionContext> = {
+      name: 'main',
+      handoffs: [specialist],
+    };
+
+    expect(validConfig.handoffs).toEqual([specialist]);
+
+    const invalidConfig: RealtimeAgentConfiguration<OtherContext> = {
+      name: 'incompatible',
+      // @ts-expect-error - mismatched handoff context should not be allowed
+      handoffs: [specialist],
+    };
+
+    expect(invalidConfig).toBeDefined();
+  });
+});