Harness
The context, state, tools, control, and interaction substrate that turns a model into an operating product.
GLOSSARY + SOURCE INDEX
From plain-language glossary to official source
Terms create a shared language; source anchors constrain interpretation. Every explanation is pinned to an auditable snapshot.
UPSTREAM RESEARCH SNAPSHOT
47f943859bef60e4160492346772ded9b24f765a2026-08-13 · 324 docs · 3746 package filesPLAIN-LANGUAGE GLOSSARY
Fifteen terms that remove reading friction
Context
Cordis's scoped container for services, events, config, and reversible effects.
Effect
A plugin-owned resource plus its disposer, making setup and teardown symmetric.
Fiber
An async work unit with parentage, cancellation, and cleanup semantics.
Profile
A named product composition that selects bundles and carries user patches.
EpochHeader
The complete snapshot of model, tools, prompt, and limits seen by one model request.
Turn
A settlement unit that claims one input and may contain multiple steps.
Step
One model request and stream; a tool loop starts another step.
SessionEvent
Append-only, replayable, model-visible session truth—not the same as UI display order.
Surface
The model-context view projected from the log; compaction changes the surface, not history.
Capability seam
A replacement boundary formed by a service definition, providers, consumers, and policy consumers.
Tool debt
The obligation to return a matching result after a model emits a tool call.
Projection
An event-derived read model using watermarks to avoid duplicate or out-of-order consumption.
Spill
Moving oversized content out of context and leaving an opaque locator for later retrieval.
Provider
One implementation of a capability contract, owning its config, SDK, and resource lifecycle.
CURATED SOURCE MAP
Organized by learning layer, not dumped as a tree
Each file appears beside the question it answers best. Read the chapter, then verify the source.
Build the mental model
Explain the boundary between model, agent, and harness
Learn the composition grammar
Read why a real plugin tree can mount, replace, and unwind
Trace the agent spine
Explain a complete model request event by event
Understand safety and durability
Judge whether the system stays trustworthy under denial, crashes, cancellation, and long context
Scale beyond one agent
Separate state, delegation, orchestration, and long-running work
Build and ship extensions
Ship a capability without patching the agent loop
PRIMARY SOURCE
This project builds the bridge; upstream settles the facts
DeepSeek Harness remains in developer preview. For contract, event-name, or default changes, use the current official commit.