Simulation & evaluation
Arena Intelligence
A fictional real-time simulation combining asynchronous AI reasoning, validated control, and exact replay.
My roleDesigned and built the C++20 simulation engine, Python agent pipeline, and React review workspace.
Released v0.2.0 · October 2026
Explore the workflowInteractive walkthrough
Trace a recorded decision.
Inspect a recorded run from available evidence through control validation and outcome scoring.
Select a stage to inspect its role in the workflow.
Step 4: Outcome. Keep the missed outcome in the record.
- Observed88.0s
- Cutoff90.0s
- Applied103.6s
- Horizon120.0s
Post-run result: a missed forecast, preserved for review.
Step 04 / Inspect
Keep the missed outcome in the record.
At 120 seconds, the evaluator recorded node 1 rather than the predicted node 2. The forecast missed despite passing the acceptance checks. This outcome is post-run evaluator data and was not available to the agent at forecast time.
predicted: node 2 / 88%
recorded outcome: node 1
forecast: incorrect
Brier score: 1.6992
status: scored
assignment active through horizonRecorded scenario 004 · request r3 · observer evidence and evaluator results stay separate.
Recorded synthetic scenario 004. Controls inspect the saved run; no new inference is performed.
Inspect the source recordingResults
- Exact replay verified across 102 runs and 177,052 canonical states, with zero API calls.
- 131 Python tests and five frontend tests; CI covers Linux, macOS, frontend checks, and sanitizers.
- Recorded comparison: 120/144 correct forecasts with analyst/challenger reasoning versus 119/144 for one agent, at roughly twice the latency.
Engineering details
Agent reasoning can arrive after its observations become stale. Arena separates inference from deterministic control and records every accepted decision.
Real-time control
A deterministic C++20 engine runs at 10 Hz while Python executes an analyst, evidence checks, and a challenger asynchronously.
Validated decisions
Schema, evidence, timing, and assignment checks gate recommendations before atomic application at a tick boundary.
Exact replay
The React workspace exposes evidence and timing; SQLite records sessions for replay without new model calls.