agent runtime verification loop + examples

README.md

@@ -830,6 +830,40 @@ with browser:
 
 </details>
 
+<details>
+<summary><h3>🔍 Agent Runtime Verification</h3></summary>
+
+`AgentRuntime` provides assertion predicates for runtime verification in agent loops, enabling programmatic verification of browser state during execution.
+
+```python
+from sentience import (
+    AgentRuntime, SentienceBrowser,
+    url_contains, exists, all_of
+)
+from sentience.tracer_factory import create_tracer
+
+browser = SentienceBrowser()
+browser.start()
+tracer = create_tracer(run_id="my-run", upload_trace=False)
+runtime = AgentRuntime(browser, browser.page, tracer)
+
+# Navigate and take snapshot
+browser.page.goto("https://example.com")
+runtime.begin_step("Verify page")
+runtime.snapshot()
+
+# Run assertions
+runtime.assert_(url_contains("example.com"), "on_correct_domain")
+runtime.assert_(exists("role=heading"), "has_heading")
+runtime.assert_done(exists("text~'Example'"), "task_complete")
+
+print(f"Task done: {runtime.is_task_done}")
+```
+
+**See example:** [`examples/agent_runtime_verification.py`](examples/agent_runtime_verification.py)
+
+</details>
+
 <details>
 <summary><h3>🧰 Snapshot Utilities</h3></summary>
 

examples/agent_runtime_verification.py

@@ -0,0 +1,126 @@
+"""
+Example: Agent Runtime with Verification Loop
+
+Demonstrates how to use AgentRuntime for runtime verification in agent loops.
+The AgentRuntime provides assertion predicates to verify browser state during execution.
+
+Key features:
+- Predicate helpers: url_matches, url_contains, exists, not_exists, element_count
+- Combinators: all_of, any_of for complex conditions
+- Task completion: assert_done() for goal verification
+- Trace integration: Assertions emitted to trace for Studio timeline
+
+Requirements:
+- SENTIENCE_API_KEY (Pro or Enterprise tier)
+
+Usage:
+    python examples/agent_runtime_verification.py
+"""
+
+import os
+
+from sentience import (
+    AgentRuntime,
+    SentienceBrowser,
+    all_of,
+    exists,
+    not_exists,
+    url_contains,
+    url_matches,
+)
+from sentience.tracer_factory import create_tracer
+
+
+def main():
+    # Get API key from environment
+    sentience_key = os.environ.get("SENTIENCE_API_KEY")
+
+    if not sentience_key:
+        print("Error: SENTIENCE_API_KEY not set")
+        return
+
+    print("Starting Agent Runtime Verification Demo\n")
+
+    # 1. Create tracer for verification event emission
+    run_id = "verification-demo"
+    tracer = create_tracer(api_key=sentience_key, run_id=run_id, upload_trace=False)
+    print(f"Run ID: {run_id}\n")
+
+    # 2. Create browser
+    browser = SentienceBrowser(api_key=sentience_key, headless=False)
+    browser.start()
+
+    try:
+        # 3. Create AgentRuntime with browser, page, and tracer
+        runtime = AgentRuntime(browser, browser.page, tracer)
+
+        # 4. Navigate to a page
+        print("Navigating to example.com...\n")
+        browser.page.goto("https://example.com")
+        browser.page.wait_for_load_state("networkidle")
+
+        # 5. Begin a verification step
+        runtime.begin_step("Verify page loaded correctly")
+
+        # 6. Take a snapshot (required for element assertions)
+        snapshot = runtime.snapshot()
+        print(f"Snapshot taken: {len(snapshot.elements)} elements found\n")
+
+        # 7. Run assertions against current state
+        print("Running assertions:\n")
+
+        # URL assertions
+        url_ok = runtime.assert_(url_contains("example.com"), "on_example_domain")
+        print(f"  [{'PASS' if url_ok else 'FAIL'}] on_example_domain")
+
+        url_match = runtime.assert_(url_matches(r"https://.*example\.com"), "url_is_https")
+        print(f"  [{'PASS' if url_match else 'FAIL'}] url_is_https")
+
+        # Element assertions
+        has_heading = runtime.assert_(exists("role=heading"), "has_heading")
+        print(f"  [{'PASS' if has_heading else 'FAIL'}] has_heading")
+
+        no_error = runtime.assert_(not_exists("text~'Error'"), "no_error_message")
+        print(f"  [{'PASS' if no_error else 'FAIL'}] no_error_message")
+
+        # Combined assertion with all_of
+        page_ready = runtime.assert_(
+            all_of(url_contains("example"), exists("role=link")),
+            "page_fully_ready",
+        )
+        print(f"  [{'PASS' if page_ready else 'FAIL'}] page_fully_ready")
+
+        # 8. Check if task is done (required assertion)
+        task_complete = runtime.assert_done(
+            exists("text~'Example Domain'"),
+            "reached_example_page",
+        )
+        print(f"\n  [{'DONE' if task_complete else 'NOT DONE'}] reached_example_page")
+
+        # 9. Get accumulated assertions for step_end event
+        assertions_data = runtime.get_assertions_for_step_end()
+        print(f"\nTotal assertions: {len(assertions_data['assertions'])}")
+        print(f"Task done: {assertions_data.get('task_done', False)}")
+
+        # 10. Check overall status
+        print("\nVerification Summary:")
+        print(f"  All passed: {runtime.all_assertions_passed()}")
+        print(f"  Required passed: {runtime.required_assertions_passed()}")
+        print(f"  Task complete: {runtime.is_task_done}")
+
+    except Exception as e:
+        print(f"\nError during execution: {e}")
+        raise
+
+    finally:
+        # Close tracer and browser
+        print("\nClosing tracer...")
+        tracer.close(blocking=True)
+        print(f"Trace saved to: ~/.sentience/traces/{run_id}.jsonl")
+
+        browser.close()
+        print("Done!")
+
+
+if __name__ == "__main__":
+    main()

sentience/__init__.py

@@ -5,6 +5,7 @@
 from .actions import click, click_rect, press, scroll_to, type_text
 from .agent import SentienceAgent, SentienceAgentAsync
 from .agent_config import AgentConfig
+from .agent_runtime import AgentRuntime
 
 # Agent Layer (Phase 1 & 2)
 from .base_agent import BaseAgent
@@ -70,6 +71,21 @@
 
 # Formatting (v0.12.0+)
 from .utils.formatting import format_snapshot_for_llm
+
+# Verification (agent assertion loop)
+from .verification import (
+    AssertContext,
+    AssertOutcome,
+    Predicate,
+    all_of,
+    any_of,
+    custom,
+    element_count,
+    exists,
+    not_exists,
+    url_contains,
+    url_matches,
+)
 from .visual_agent import SentienceVisualAgent, SentienceVisualAgentAsync
 from .wait import wait_for
 
@@ -160,4 +176,17 @@
     # Enums
     "SentienceMethod",
     "AgentAction",
+    # Verification (agent assertion loop)
+    "AgentRuntime",
+    "AssertContext",
+    "AssertOutcome",
+    "Predicate",
+    "url_matches",
+    "url_contains",
+    "exists",
+    "not_exists",
+    "element_count",
+    "all_of",
+    "any_of",
+    "custom",
 ]