The plugin for coding agents: Claude Code, Codex, GitHub Copilot

The ddd-ts-kit repository is the marketplace of the plugin for the three agents:

Agent	Install	A skill is called
Claude Code	/plugin marketplace add gbourgeat/ddd-ts-kit, then /plugin install ddd-ts-kit@ddd-ts-kit	/ddd-ts-kit:start
Codex	codex plugin marketplace add gbourgeat/ddd-ts-kit, then install ddd-ts-kit from /plugins and trust its hooks in /hooks	$start
Copilot CLI	copilot plugin marketplace add gbourgeat/ddd-ts-kit, then copilot plugin install ddd-ts-kit@ddd-ts-kit	by its name, start
Copilot cloud agent, VS Code	declared by the .github/copilot/settings.json that init writes: the cloud agent installs it, VS Code recommends it	by its name, start

Twenty-two skills, in the order a project meets them:

Skill	Use
start	conduct a project from a statement of needs to working contexts (run by the user)
discover-domain	a light event storming in writing
bounded-contexts	find the contexts and classify them core, supporting or generic
glossary	the ubiquitous language of a context and its CONTEXT.md, before any code
context-map	upstream, downstream and relationship pattern for each pair of contexts
bootstrap	choose the stack and create the project (run by the user)
plan-slices	the work as vertical slices per context, ordered, with their generator commands
parallel-work	split the slices between several agents or people without collision
scaffold	one file of any role, from a template
use-case	one feature end to end, test first
integration-event	make two contexts collaborate through a versioned event
wiring	ports as abstract classes, declarations, the composition root, fakes in tests
persistence	repositories, unit of work, outbox, read models, migrations, whatever the ORM
access-control	authentication, permissions per use case, the explicit actor, policies
cross-cutting	logging, metrics, tracing, error reporting, audit trail, resilience and caching from outside
testing	fakes instead of mocks, builders, given / when / then, end to end
clean-code	naming, function order, comments, testability
document	OpenAPI contract and its typed clients, event catalog, AsyncAPI, generated lists, decision records
extract-service	keep each context ready to run as its own service, and extract it
deviation	what to do when asked to go around a rule
quality-gate	run the checks at the right scope and fix at the root cause
commit-discipline	one slice per commit, generated files with what generated them

Four agents: domain-explorer (read-only answers about what exists and where), context-builder (builds the slices of one context in its own worktree), domain-test-writer (turns it.todo entries into specs) and architecture-reviewer (read-only review of a diff, a branch or a context).

The hook is the part that makes the rest binding. In a project that has a ddd-ts-kit.config.json it reminds the workflow and the context map at session start, says when the installed packages are not the version the skills describe, refuses a hand-written file where a generator exists and any edit of a generated contract, asks the project owner before a suppression, a skipped test or a change of the rules is written, checks every written file and returns the violations with their fix, and refuses to finish while architecture errors remain. It reminds, without blocking, when the uncommitted changes exceed the advised size of a commit, and in a worker's worktree (.ddd-ts-kit/worker.json) it refuses a write outside the worker's context. It fails open: a broken guard never blocks work. Set "guard": "advise" in the config to be asked instead of refused, "off" to silence it.

Each agent gets what its host runs. The skills work in all three. The four agents are sub-agents of Claude Code; Codex loads no agent from a plugin, and one session per worktree takes the place of context-builder. The hook runs wherever the host runs the hooks of a plugin: it reads the patches of Codex and the tool calls of Copilot as well as those of Claude Code. Codex cannot put a question to the user, so what Claude Code asks the project owner is said to the user there, and left to the checks of the pipeline.

Without any plugin, a project still guides every agent: init writes AGENTS.md, the guide Codex, Copilot and most agents read (CLAUDE.md imports it), the rules by layer for Claude Code in .claude/rules/ and the same rules for Copilot in .github/instructions/, scoped by applyTo, and, with the GitHub pipeline, copilot-setup-steps.yml, which installs the project before the Copilot cloud agent starts. npm run verify and the pipeline hold every agent to the same rules.