ctx-adopt — bring an existing project under ctx, minimally

Brownfield entry: makes ctx take effect on an existing (usually messy) project without touching what the user has — it orchestrates; the domain skills do the real writing. Lifetime model: [../ctx](../ctx/SKILL.md).

The one principle: stable mount point, swappable backend

/ctx is a mount point at the project root — the fixed place any agent looks for context. Its backend (where the bytes live) is swappable. The agent always reads <repo>/ctx; whether that is a real folder or a symlink is a deployment detail.

Three rules — what "low-disruption" MEANS

1. NEVER restructure the user's existing directories. Only ADD the /ctx mount + one pointer line.
2. Default to the lightest backend (in-repo real dir). Upgrade only when separability is actually needed.
3. Reorganize the user's tree only when the user asks, or when building ctx makes a change unavoidable — and even then guarantee one thing: ctx logic stays valid.

Execution Procedure

EP1 — pick the backend

if project is published (LICENSE + public remote + package-registry footprint):
    backend = EXTERNAL SYMLINK           # context must not ship with public code
             <repo>/ctx  ->  ../<project>-ctx/     (symlink gitignored; real bytes live outside the code repo)
else:
    backend = IN-REPO DIR                # default, zero setup, minimal footprint
             <repo>/ctx/   (real folder; commit if the repo is private, gitignore if not ready to share)

Naming: the mount is /ctx inside the project's own directory. When the project name must be attached to a standalone ctx artifact (the external store, or loose files sharing a parent), use the suffix form <project>-ctx — it reads as "the ctx of <project>" and keeps a project and its ctx adjacent in a directory listing.

The external store's exact home (a sibling dir ../<project>-ctx/, a private repo, or a shared
machine store) is a deployment detail — default to the sibling dir. Do NOT invent a central
store unless the user has many repos AND asks for one.

EP2 — announce it (pointer: tool-agnostic, agent-aware)

The real interop contract is the /ctx folder (vendor-neutral, like .git). The pointer file is only a convenience:

if AGENTS.md exists:    add the pointer line to AGENTS.md      # respect the project's choice
                        # @AGENTS.md BRIDGE: if the running agent is Claude Code, ALSO ensure a
                        # CLAUDE.md exists that imports it — a single line `@AGENTS.md`. Claude Code
                        # does NOT read AGENTS.md, so without this import a CC session never sees the
                        # pointer (or any other AGENTS.md instruction). One line bridges both worlds.
elif CLAUDE.md exists:  add the pointer line to CLAUDE.md
else (neither):         the RUNNING AGENT writes its own native file
                        (Claude Code -> CLAUDE.md; Codex/Cursor/Windsurf/... -> AGENTS.md)
# never force the user to switch vendors

Fallback: the ctx skill's description is system-prompt-resident, so any agent with ctx installed recognizes a ctx knowledge base is in play even with no pointer file — and once it loads the skill body, /ctx is the mount point stated there. Pointer line (one line): Project context & docs live in ./ctx — managed by the ctx skills; apply their consistency rules when editing ctx docs.

EP3 — sort the scattered docs (DELEGATE — do not re-implement)

Scan the existing tree for doc-shaped content, classify each by lifetime, and route each to the domain skill that owns writing it. ctx-adopt decides where a thing goes; the domain skill decides how it is written to standard:

Produce a migration plan (found → ctx home → delegated skill → action), show it to the user, move nothing until approved. Never touch code files. This routing is what stops ctx-adopt from emitting shallow, standard-violating spec/decision stubs — the domain skills carry the format.

EP4 — code-topology check (last, subordinate, respectful)

After ctx is in place, assess whether the repo itself would benefit from a structural change (docs & code hopelessly interleaved; a monorepo that should split). Surface it as a recommendation with rationale. Act only if (a) the user asks, or (b) building ctx made a repo change unavoidable. Default: respect the repo as-is. (Absorbed repo-scaffold concern — code topology serves ctx, never drives it; greenfield code skeletons are a one-line starter note, not a system.)

Definition of done (stop condition = standard)

• /ctx mount exists at the right place with the right backend.
• pointer line added to the correct file (or skipped, with the description-fallback noted).
• confidentiality gate: backend holds secrets AND code repo is public → /ctx is a gitignored symlink out, verified never committed.
• migration plan produced (executed if approved) via the delegated domain skills; no code files moved.
• the ctx-folder DoD checklist (../ctx/references/consistency.md § Rule 4 (the gate); skeleton model in ../ctx/SKILL.md § The canonical folder) passes.

Routes to

ctx (model) · ctx-merge (converge) · ctx-spec (spec/ADR) · ctx-progress (progress) · ctx-report (reports). Absorbs the former repo-scaffold.