diff --git a/sandbox/sdk/python/errors.mdx b/sandbox/sdk/python/errors.mdx
index 0ca4188..041b4b6 100644
--- a/sandbox/sdk/python/errors.mdx
+++ b/sandbox/sdk/python/errors.mdx
@@ -11,6 +11,7 @@ from porter_sandbox import (
     NotFoundError,
     RateLimitError,
     SandboxError,
+    SandboxTimeoutError,
     ServerError,
 )
 ```
@@ -24,6 +25,7 @@ from porter_sandbox import (
 | `NotFoundError` | A sandbox, volume, or other resource cannot be found. |
 | `RateLimitError` | The API returns a rate limit response. |
 | `ServerError` | The API returns a server-side error. |
+| `SandboxTimeoutError` | A request exceeds its timeout. Never retried, since the server may still be executing the request. |
 
 Each `SandboxError` includes:
 
diff --git a/sandbox/sdk/python/reference.mdx b/sandbox/sdk/python/reference.mdx
index 5e522ef..4d306ec 100644
--- a/sandbox/sdk/python/reference.mdx
+++ b/sandbox/sdk/python/reference.mdx
@@ -102,10 +102,25 @@ sandbox.terminate()
 | Method | Description |
 | ------ | ----------- |
 | `refresh()` | Refetches status and updates `phase` and `tags`. |
-| `exec(command)` | Runs a command in the sandbox and returns stdout, stderr, and exit code. |
+| `exec(command, timeout=None)` | Runs a command in the sandbox and returns stdout, stderr, and exit code. |
 | `logs(since=None, limit=None)` | Fetches structured log lines. |
 | `terminate()` | Terminates the sandbox. |
 
+### `exec` timeouts
+
+`exec` is long-running: the client sends no timeout by default, so the call waits for the command to exit. Pass `timeout` (seconds) to cap how long the client waits. When the timeout elapses, the SDK raises `SandboxTimeoutError` and does not retry, since the command may still be running server-side.
+
+```python
+from porter_sandbox import SandboxTimeoutError
+
+try:
+    result = sandbox.exec(["sleep", "120"], timeout=30.0)
+except SandboxTimeoutError:
+    print("exec exceeded 30s; the command may still be running in the sandbox")
+```
+
+The client-wide `timeout` on `Porter` still applies to every other request (30 seconds by default).
+
 ## Volumes
 
 Volumes are persistent storage that can be mounted into sandboxes.
diff --git a/sandbox/sdk/typescript/errors.mdx b/sandbox/sdk/typescript/errors.mdx
index 4565c7e..e234489 100644
--- a/sandbox/sdk/typescript/errors.mdx
+++ b/sandbox/sdk/typescript/errors.mdx
@@ -11,6 +11,7 @@ import {
   NotFoundError,
   RateLimitError,
   SandboxError,
+  SandboxTimeoutError,
   ServerError,
 } from "porter-sandbox";
 ```
@@ -24,6 +25,7 @@ import {
 | `NotFoundError` | A sandbox, volume, or other resource cannot be found. |
 | `RateLimitError` | The API returns a rate limit response. |
 | `ServerError` | The API returns a server-side error. |
+| `SandboxTimeoutError` | A request exceeds its timeout. Never retried, since the server may still be executing the request. |
 
 Each `SandboxError` includes:
 
diff --git a/sandbox/sdk/typescript/reference.mdx b/sandbox/sdk/typescript/reference.mdx
index e51fecb..35906c7 100644
--- a/sandbox/sdk/typescript/reference.mdx
+++ b/sandbox/sdk/typescript/reference.mdx
@@ -109,10 +109,30 @@ await sandbox.terminate();
 | Method | Description |
 | ------ | ----------- |
 | `refresh()` | Refetches status and updates `phase` and `tags`. |
-| `exec(command)` | Runs a command in the sandbox and returns stdout, stderr, and exit code. |
+| `exec(command, requestOptions?)` | Runs a command in the sandbox and returns stdout, stderr, and exit code. |
 | `logs(options?)` | Fetches structured log lines. |
 | `terminate()` | Terminates the sandbox. |
 
+### `exec` timeouts
+
+`exec` is long-running: the client sends no timeout by default, so the call waits for the command to exit. Pass `requestOptions.timeoutMs` to cap how long the client waits. When the timeout elapses, the SDK throws `SandboxTimeoutError` and does not retry, since the command may still be running server-side.
+
+```typescript
+import { SandboxTimeoutError } from "porter-sandbox";
+
+try {
+  const result = await sandbox.exec(["sleep", "120"], { timeoutMs: 30_000 });
+} catch (error) {
+  if (error instanceof SandboxTimeoutError) {
+    console.error("exec exceeded 30s; the command may still be running in the sandbox");
+  } else {
+    throw error;
+  }
+}
+```
+
+The client-wide `timeoutMs` on `Porter` still applies to every other request (30 seconds by default).
+
 ## Volumes
 
 Volumes are persistent storage that can be mounted into sandboxes.