oharness-core

Core types, event schema, and context-plumbing traits for open-harness — the kernel-style research framework for LLM agent loops.

oharness-core is the foundation crate: every other crate in the workspace depends on it. It deliberately carries no IO, no async executor, no provider integrations — it's serde types + traits other crates implement.

What's in here

• Event schema (Event, EventKind, SchemaVersion) — the trajectory format. Governed by CHANGELOG-schema.md; the JSON Schema lives at schema/events-v1.0.json.
• Message / Content — Message::{User,Assistant,System}, Content::{Text,ToolUse,ToolResult,Image,…} — the building blocks every provider adapter speaks.
• Task / RunOutcome / Termination — the top-level shape an agent run takes in and produces.
• AssistantTurn / AssessmentContext / Episode — critic / reflector-facing views.
• TaskEvaluator trait — lives here (not in oharness-eval) so the loop crate can take evaluators without pulling the eval crate.
• ScopedEmitter + EventSink — the event-emission abstraction every other crate consumes.

When to use this crate directly

• You're writing a trait implementation (Llm, Critic, MemoryPolicy, ToolSet, Reflector, UserSimulator, TaskEvaluator) and need only the plain data types.
• You're consuming a trajectory file programmatically (use oharness-trace for the JSONL reader; deserialize into Event types from here).

Most users pull in oharness-loop and get this transitively.

License

Dual-licensed under MIT or Apache-2.0 (see LICENSE-MIT / LICENSE-APACHE at the workspace root).