Answers the 3 adoption questions (Plan-21 follow-up):
1) LEVEL SELECTION (4 packaging levels, packaging/levels.json):
- install.sh --level core|devkit; platform refused (preview service),
enterprise refused (future). Level recorded in .casan-level.
- casan init --level 1..4: L1=gate+Plan-20 hooks only; L2=+CI+domain-pack;
L3=L2 base+preview note; L4=refused. New `casan level show|set`.
- levels.json core now includes adapters/ + schemas/ + install scripts.
2) EXISTING SHELLS (agents/skills): init MERGES Plan-20 hooks into an existing
.claude/settings.json and .codex/{hooks.json,config.toml} idempotently
instead of clobbering — preserves the project's own hooks/agents/skills and
unrelated keys. Re-running never duplicates the CASAN hook.
3) NO RE-INDEX / NO SHELL REWRITE: init only adds config; it does not parse or
index code and does not rewrite the project shell.
Safety fixes after a test accidentally ran init in the real repo:
- launcher shim now SELF-LOCATES its install from its own path (no ambient
CASAN_HOME cross-talk).
- casan init REFUSES to adopt a CASAN source hub into itself (--force to
override), so the Plan-20 hooks can't block the developing agent.
- test always runs init inside throwaway dirs; +source-hub guard test.
hybrid-install-tests.sh: 41/41 PASS.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Adopt CASAN like a normal tool (codegraph-style): install the harness ONCE
per machine, then `casan init` per project writes CONFIG ONLY — the harness
is no longer copied into every repo.
- install.sh / install.ps1: global bootstrap (curl|sh / irm|iex or local
source). Installs harness to $CASAN_HOME/versions/<ver>, writes a `casan`
launcher that resolves the shared harness + the current project's .specify,
and records a gate-code integrity hash. CASAN_NO_PATH_LINK for tests.
- harness_hash.py: deterministic content hash over gate code (scripts/bash,
scripts/python, security, level5) — the pin+verify anchor.
- casan-init.py: `casan init` writes .casan/{config,version.lock,agentic.env},
.specify/ marker, and the Plan-20 client hooks — no harness copy. `verify`
recomputes the harness hash LIVE and compares to the project pin (drift/
tamper -> rc 3), preserving the Plan-16 trusted-gates guarantee off-repo.
- bin/casan: new `init` and `verify-harness` commands.
- hybrid-install-tests.sh: 21/21 (install, config-only init, no-copy, pin,
verify ok, tamper drift, bridge runs against project state via global harness).
- docs: CASAN_INSTALL_HYBRID.md + Plan-21.
The path model (casan-paths.sh) already separated harness/state/domain roots,
so this is installer + init, not a core rewrite. Remote dist tarball, real
Windows run, and signed .harness-hash are the documented next steps.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
