hz.Handuo Zhang
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Project

Prax / AgentOS and ApodexHarness

I joined Apodex in late March 2026 as one of three founding engineers of Prax / AgentOS and became the technical owner of ApodexHarness infrastructure. The project develops an execution system for complex, long-running tasks.

Harness architecture

Apodex Harness architecture: API, SDK, and worker shell entry points feed workflow assembly and a NodeContext runtime facade; a generic runtime core manages scheduling, agents, resources, and events, with external services and an optional state sidecar.
Harness architecture: task entry points, workflow assembly, the runtime core, external execution resources, and an optional state sidecar. Select the diagram to read it at full size.

I built heavy_mode, which combines parallel sub-agents, cross-branch synthesis, global verification, and continuation after interruption. I proposed planner-generated, schema-constrained workflow DAGs and replaced a LangGraph dependency with a compact execution engine supporting branches and verification-retry loops.

I also developed token-budgeted context compression, file-based research memory, tool-specific result budgets, and evidence checks for unsupported numbers and citations. Reliability work included durable agent messages, sandbox isolation, tool permissions, and cancellation-safe event streaming.

The harness connects workflows to a unified evaluation interface. I supported the Apodex 1.1 and 1.2 model releases and ran 240 APEX Agents 1.1 tasks end to end to validate the evaluation path.

Apodex 1.1: Agent Team state and artifact delivery

For Apodex 1.1, the harness added a more explicit contract for coordinated agents. The coordinator owns task resolution on an external task board, while the Agent Bus tracks asynchronous subagent execution. Candidate work stays in agent workspaces or shared scratch space; a single publisher lease and an exact manifest gate determine which files become collected outputs. Live user follow-ups can enter the same run without losing the task state.

Apodex 1.1 Agent Team state contract: a coordinator, external task board, and Agent Bus coordinate subagents; workspace candidates pass through a single publisher lease and exact manifest gate to collected outputs.
Apodex 1.1 Agent Team state contract, showing coordination, workspace isolation, and controlled publication of final artifacts. Select the diagram to read it at full size.