Make your own event-sourced agent harness using stream processors — Jonas Templestein, Iterate
TL;DR
Jonas Templestein and Misha from Iterate demonstrate a prototype event-sourced architecture for building distributed AI agent harnesses where all state changes are captured as immutable events in HTTP-accessible streams, enabling debuggability and composability across different languages and environments.
💡 Event-Sourced Architecture Philosophy 2 insights
Immutable event logs enable perfect debugging
Every state change is captured as an event with a type and payload, creating a complete audit trail that makes agent behavior fully reproducible and transparent.
Single abstraction simplifies system design
The architecture treats everything—from LLM responses to errors and scheduled tasks—as uniform events, eliminating complex side effects and special cases found in traditional agent frameworks.
🌐 Distributed & Edge-First Design 2 insights
Publicly routable HTTP endpoints for every agent
Agents exist as internet-connected server programs with unique URLs from creation, eliminating the need for connector frameworks to integrate external services like Slack or web forms.
Cross-language composability
Plugins and extensions can run on different machines written in different languages (Rust, TypeScript) and communicate purely through the event stream interface.
⚙️ Technical Implementation & Safety 3 insights
Circuit breaker prevents infinite loops
Streams automatically pause when exceeding 100 events per second, requiring manual intervention to resume and preventing runaway feedback loops between distributed components.
Native scheduling and webhook support
The system supports scheduled events (heartbeats, future tasks) and bidirectional HTTP subscriptions via Server-Sent Events, allowing agents to both consume and push events to external endpoints.
Tolerance for unstructured data
The API accepts arbitrary webhook payloads from third parties without strict validation, relying on LLMs to parse unstructured data rather than enforcing rigid schemas.
Bottom Line
Build AI agent harnesses as distributed, event-sourced systems with immutable logs and HTTP-native interfaces to maximize debuggability, composability, and interoperability across different languages and environments.
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