hook for redacting PII for screenshots

sentience/tracer_factory.py

@@ -1,5 +1,3 @@
-from typing import Optional
-
 """
 Tracer factory with automatic tier detection.
 
@@ -10,7 +8,8 @@
 import os
 import uuid
 from pathlib import Path
-from typing import Any
+from typing import Any, Optional
+from collections.abc import Callable
 
 import requests
 
@@ -31,6 +30,7 @@ def create_tracer(
     agent_type: str | None = None,
     llm_model: str | None = None,
     start_url: str | None = None,
+    screenshot_processor: Callable[[str], str] | None = None,
 ) -> Tracer:
     """
     Create tracer with automatic tier detection.
@@ -55,6 +55,9 @@ def create_tracer(
         agent_type: Type of agent running (e.g., "SentienceAgent", "CustomAgent")
         llm_model: LLM model used (e.g., "gpt-4-turbo", "claude-3-5-sonnet")
         start_url: Starting URL of the agent run (e.g., "https://amazon.com")
+        screenshot_processor: Optional function to process screenshots before upload.
+                            Takes base64 string, returns processed base64 string.
+                            Useful for PII redaction or custom image processing.
 
     Returns:
         Tracer configured with appropriate sink
@@ -71,6 +74,17 @@ def create_tracer(
         ... )
         >>> # Returns: Tracer with CloudTraceSink
         >>>
+        >>> # With screenshot processor for PII redaction
+        >>> def redact_pii(screenshot_base64: str) -> str:
+        ...     # Your custom redaction logic
+        ...     return redacted_screenshot
+        >>>
+        >>> tracer = create_tracer(
+        ...     api_key="sk_pro_xyz",
+        ...     screenshot_processor=redact_pii
+        ... )
+        >>> # Screenshots will be processed before upload
+        >>>
         >>> # Free tier user
         >>> tracer = create_tracer(run_id="demo")
         >>> # Returns: Tracer with JsonlTraceSink (local-only)
@@ -133,6 +147,7 @@ def create_tracer(
                             api_url=api_url,
                             logger=logger,
                         ),
+                        screenshot_processor=screenshot_processor,
                     )
                 else:
                     print("⚠️  [Sentience] Cloud init response missing upload_url")
@@ -191,7 +206,11 @@ def create_tracer(
     local_path = traces_dir / f"{run_id}.jsonl"
     print(f"💾 [Sentience] Local tracing: {local_path}")
 
-    return Tracer(run_id=run_id, sink=JsonlTraceSink(str(local_path)))
+    return Tracer(
+        run_id=run_id,
+        sink=JsonlTraceSink(str(local_path)),
+        screenshot_processor=screenshot_processor,
+    )
 
 
 def _recover_orphaned_traces(api_key: str, api_url: str = SENTIENCE_API_URL) -> None:

sentience/tracing.py

@@ -10,6 +10,7 @@
 from datetime import datetime
 from pathlib import Path
 from typing import Any, Optional
+from collections.abc import Callable
 
 from .models import TraceStats
 from .trace_file_manager import TraceFileManager
@@ -163,10 +164,36 @@ class Tracer:
 
     Manages sequence numbers and provides convenient methods for emitting events.
     Tracks execution statistics and final status for trace completion.
+
+    Args:
+        run_id: Unique identifier for this trace run
+        sink: TraceSink implementation for writing events
+        screenshot_processor: Optional function to process screenshots before emission.
+                            Takes base64 string, returns processed base64 string.
+                            Useful for PII redaction or custom image processing.
+
+    Example:
+        >>> from sentience import Tracer, JsonlTraceSink
+        >>>
+        >>> # Basic usage
+        >>> sink = JsonlTraceSink("trace.jsonl")
+        >>> tracer = Tracer(run_id="abc123", sink=sink)
+        >>>
+        >>> # With screenshot processor for PII redaction
+        >>> def redact_pii(screenshot_base64: str) -> str:
+        ...     # Your custom redaction logic
+        ...     return redacted_screenshot
+        >>>
+        >>> tracer = Tracer(
+        ...     run_id="abc123",
+        ...     sink=sink,
+        ...     screenshot_processor=redact_pii
+        ... )
     """
 
     run_id: str
     sink: TraceSink
+    screenshot_processor: Callable[[str], str] | None = None
     seq: int = field(default=0, init=False)
     # Stats tracking
     total_steps: int = field(default=0, init=False)
@@ -196,6 +223,11 @@ def emit(
         self.seq += 1
         self.total_events += 1
 
+        # Apply screenshot processor if configured and screenshot is present
+        if self.screenshot_processor and "screenshot_base64" in data:
+            data = data.copy()  # Don't modify the original dict
+            data["screenshot_base64"] = self.screenshot_processor(data["screenshot_base64"])
+
         # Generate timestamps
         ts_ms = int(time.time() * 1000)
         ts = time.strftime("%Y-%m-%dT%H:%M:%S.000Z", time.gmtime())