Architecture
The workflow-server is a small state machine wrapped in an MCP tool surface. Agents call tools; the server validates every request against the workflow definition, composes techniques and resources just in time, and persists canonical session state on disk under the engineering root (feature work under a separate workspace root). The architecture is organized as models — dispatch, checkpoints, state, artifacts, resolution, and fidelity — so long-running, multi-agent runs stay bounded, pauses reach the user-facing agent, and transitions never depend on guesswork.
Models
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1. Hierarchical dispatch
Three agent layers — a user-facing meta orchestrator, a per-workflow orchestrator, and ephemeral activity workers — with clear boundaries between user interaction, state management, and task execution.
Dispatch model -
2. Just-in-time checkpoints
Declarative gates that pause execution for user decisions. Yields bubble up from background workers to the user-facing agent; the server enforces the pause and the response timing.
Checkpoint model -
3. State management
Deterministic transitions: a schema-validated variable bag, mutation through checkpoint effects and worker outputs, and first-matching-condition transition evaluation — never a guess.
State model -
4. Artifact and workspace isolation
Strict separation between the workspace root (feature worktrees) and the engineering root (planning folders hold plans, state, and traces), with predictable artifact naming.
Artifact model -
5. Technique and resource resolution
All behaviour is composed from techniques, referenced by
Resolution model::-paths, resolved workflow-first with a sharedmetafallback, and delivered as bundles — with reference material lazy-loaded. -
6. Workflow fidelity
Seven enforcement layers — from HMAC token integrity to the execution trace — that keep agents on the defined path and make deviations visible.
Fidelity model