Glossary

Quick definitions for the terms used across the DDx docs.

Acceptance Criteria

The checked items on a bead that define when the bead is complete. Reviews check the criteria, not the developer’s memory of the conversation. See Architecture: Bead Lifecycle.

Agent Service

The DDx subsystem that dispatches work to AI harnesses behind a unified prompt envelope. Handles routing, session logging, quorum review, and execute-loop runtime. Surfaced as ddx agent ....

Bead

A self-contained unit of work with an ID, title, description, acceptance criteria, labels, and a dependency DAG edge set. Beads live in the project’s bead store as JSONL. Anything an agent does should be against a bead.

Bead Store

The on-disk JSONL store of beads inside the project (<projectRoot>/.ddx/beads/). Diffable, mergeable, branch-aware. Importable from and exportable to bd/br.

Document Library

The structured collection of agent-facing artifacts in a project — prompts, personas, patterns, templates, MCP server registry, and more. Versioned in git, syncable across projects.

Execute-Loop

The runtime that drains the bead queue. Picks a ready bead, runs an agent in an isolated worktree, has a stronger model review the result, and either merges or escalates. Invoked as ddx work or ddx agent execute-loop.

Harness

A specific agent runtime that the agent service can dispatch to — for example claude, codex, gemini, or a local qwen endpoint. All harnesses speak the same prompt envelope.

HELIX

The workflow methodology project that sits on top of DDx. Owns phases, gates, supervisory dispatch, and bounded actions. HELIX is one valid workflow on top of DDx; alternatives can exist.

Dun

The quality check runner project that sits at the top of the cost-tiered ladder. Owns check discovery, execution, and agent-friendly output of deterministic verification.

Persona

A reusable document that shapes how an agent behaves — for example code-reviewer, implementer, test-engineer, architect. Personas are composed into prompts when their bound role is dispatched.

Plugin

A package of DDx resources installed under a project. Plugins ship templates, patterns, prompts, personas, and other artifacts. The default DDx plugin lives at <projectRoot>/.ddx/plugins/ddx/ after ddx init.

Project-Local

A DDx design property: install operations only write under <projectRoot>, never under ~/. Cloning the repo gives a collaborator the full DDx surface for the project. The single global artifact is ddx-server.

Prompt Envelope

The structured composition of bead context, persona, project config, and relevant patterns that the agent service hands to a harness. The envelope is what makes harnesses interchangeable.

Quorum Review

A multi-agent dispatch mode where several harnesses review the same work and a configured policy (e.g. majority) decides the outcome.

Ready Queue

The subset of beads whose dependencies are all closed — the work that’s pickable right now. Surfaced via ddx bead ready and consumed by the execute-loop.

Role

An abstract function (e.g. “the reviewer”, “the implementer”) that a project binds to a specific persona in .ddx.yml. The execute-loop dispatches by role; bindings decide which persona, and which tier of model, fulfills it.

Skill

An agent-facing capability surface installed under <projectRoot>/.claude/skills/ or <projectRoot>/.agents/skills/. DDx ships a single consolidated ddx skill rather than a fleet of small ones.

Three-Layer Stack

The architectural separation DDx is one layer of: DDx (platform primitives), HELIX (workflow methodology), Dun (deterministic quality checks). Each layer is independently useful and replaceable. See the overview.

Worktree (Isolated)

A dedicated git worktree the execute-loop creates per bead so the agent’s edits never collide with the user’s working tree. The worktree is merged back to the base ref on success or preserved for diagnosis on failure.