diff --git a/agent_suite_sdk/__init__.py b/agent_suite_sdk/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/agent_suite_sdk/client.py b/agent_suite_sdk/client.py
new file mode 100644
index 0000000..7558016
--- /dev/null
+++ b/agent_suite_sdk/client.py
@@ -0,0 +1,47 @@
+import httpx
+from typing import List, Optional
+from .schemas import InboxResponse, InboxPublic, MessageCreate, MessageList
+
+class AgentSuiteClient:
+    def __init__(self, api_key: Optional[str] = None, base_url: str = "http://localhost:8000"):
+        self.base_url = base_url
+        self.headers = {"Authorization": f"Bearer {api_key}"} if api_key else {}
+        self.client = httpx.AsyncClient(base_url=self.base_url, headers=self.headers)
+
+    async def create_inbox(self) -> InboxResponse:
+        """Creates a new inbox and returns the API Key."""
+        response = await self.client.post("/v1/inboxes")
+        response.raise_for_status()
+        data = response.json()
+        # Update headers if we just created the account
+        self.client.headers.update({"Authorization": f"Bearer {data['api_key']}"})
+        return InboxResponse(**data)
+
+    async def get_my_inbox(self) -> InboxPublic:
+        """Gets current inbox details."""
+        response = await self.client.get("/v1/inboxes/me")
+        response.raise_for_status()
+        return InboxPublic(**response.json())
+
+    async def send_email(self, to: str, subject: str, body: str, html_body: Optional[str] = None):
+        """Sends an email."""
+        payload = {
+            "to": to,
+            "subject": subject,
+            "body": body,
+            "html_body": html_body
+        }
+        response = await self.client.post("/v1/inboxes/me/send", json=payload)
+        response.raise_for_status()
+        return response.json()
+
+    async def list_messages(self, skip: int = 0, limit: int = 50, unread_only: bool = False) -> MessageList:
+        """Lists received messages."""
+        params = {"skip": skip, "limit": limit, "unread_only": unread_only}
+        response = await self.client.get("/v1/inboxes/me/messages", params=params)
+        response.raise_for_status()
+        return MessageList(**response.json())
+
+    async def close(self):
+        """Closes the client connection."""
+        await self.client.aclose()
diff --git a/agent_suite_sdk/schemas.py b/agent_suite_sdk/schemas.py
new file mode 100644
index 0000000..d2b6e18
--- /dev/null
+++ b/agent_suite_sdk/schemas.py
@@ -0,0 +1,34 @@
+from pydantic import BaseModel, EmailStr
+from uuid import UUID
+from datetime import datetime
+from typing import List, Optional
+
+class InboxResponse(BaseModel):
+    id: UUID
+    email_address: str
+    api_key: str
+    created_at: datetime
+
+class InboxPublic(BaseModel):
+    id: UUID
+    email_address: str
+    created_at: datetime
+
+class MessageCreate(BaseModel):
+    to: EmailStr
+    subject: str
+    body: str
+    html_body: Optional[str] = None
+
+class MessageResponse(BaseModel):
+    id: UUID
+    sender: str
+    recipient: str
+    subject: Optional[str]
+    body_text: Optional[str]
+    received_at: datetime
+    is_read: bool
+
+class MessageList(BaseModel):
+    total: int
+    messages: List[MessageResponse]
diff --git a/openapi.yaml b/openapi.yaml
new file mode 100644
index 0000000..7b9eeb8
--- /dev/null
+++ b/openapi.yaml
@@ -0,0 +1,34 @@
+openapi: 3.0.0
+info:
+  title: Agent Suite API
+  version: 0.1.0
+  description: Infrastructure API for AI agents (Email without OAuth)
+servers:
+  - url: http://localhost:8000
+paths:
+  /v1/inboxes:
+    post:
+      summary: Create new inbox
+      responses:
+        '201':
+          description: Created
+  /v1/inboxes/me/send:
+    post:
+      summary: Send Email
+      security:
+        - bearerAuth: []
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                to: {type: string}
+                subject: {type: string}
+                body: {type: string}
+components:
+  securitySchemes:
+    bearerAuth:
+      type: http
+      scheme: bearer