diff --git a/pyproject.toml b/pyproject.toml
index 9eb796f..a405fd4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "sentienceapi"
-version = "0.90.9"
+version = "0.90.10"
 description = "Python SDK for Sentience AI Agent Browser Automation"
 readme = "README.md"
 requires-python = ">=3.11"
diff --git a/sentience/__init__.py b/sentience/__init__.py
index 3274adf..1d62d62 100644
--- a/sentience/__init__.py
+++ b/sentience/__init__.py
@@ -70,7 +70,7 @@
 )
 from .wait import wait_for
 
-__version__ = "0.90.9"
+__version__ = "0.90.10"
 
 __all__ = [
     # Core SDK
diff --git a/sentience/text_search.py b/sentience/text_search.py
index 66ab77b..2a2bf70 100644
--- a/sentience/text_search.py
+++ b/sentience/text_search.py
@@ -88,6 +88,49 @@ def find_text_rect(
     # Limit max_results to prevent performance issues
     max_results = min(max_results, 100)
 
+    # CRITICAL: Wait for extension injection to complete (CSP-resistant architecture)
+    # The new architecture loads injected_api.js asynchronously, so window.sentience
+    # may not be immediately available after page load
+    try:
+        browser.page.wait_for_function(
+            "typeof window.sentience !== 'undefined'",
+            timeout=5000,  # 5 second timeout
+        )
+    except Exception as e:
+        # Gather diagnostics if wait fails
+        try:
+            diag = browser.page.evaluate(
+                """() => ({
+                    sentience_defined: typeof window.sentience !== 'undefined',
+                    extension_id: document.documentElement.dataset.sentienceExtensionId || 'not set',
+                    url: window.location.href
+                })"""
+            )
+        except Exception:
+            diag = {"error": "Could not gather diagnostics"}
+
+        raise RuntimeError(
+            f"Sentience extension failed to inject window.sentience API. "
+            f"Is the extension loaded? Diagnostics: {diag}"
+        ) from e
+
+    # Verify findTextRect method exists (for older extension versions that don't have it)
+    try:
+        has_find_text_rect = browser.page.evaluate(
+            "typeof window.sentience.findTextRect !== 'undefined'"
+        )
+        if not has_find_text_rect:
+            raise RuntimeError(
+                "window.sentience.findTextRect is not available. "
+                "Please update the Sentience extension to the latest version."
+            )
+    except RuntimeError:
+        raise
+    except Exception as e:
+        raise RuntimeError(
+            f"Failed to verify findTextRect availability: {e}"
+        ) from e
+
     # Call the extension's findTextRect method
     result_dict = browser.page.evaluate(
         """