update is git-aware: cache last-run commit (meta.rev), report commits + affected modules since it, --stamp-rev

README.md

@@ -82,8 +82,11 @@ You can also run the deterministic scripts directly (no AI needed for these):
 
 ```bash
 S=~/.claude/skills/codemap
-# what changed since last audit
+# what changed since last audit — incl. a `git` block listing the commits since the
+# last codemap run (meta.rev) and which modules they touched
 python3 $S/scripts/scan.py --root . --state .claude/codemap/modules.json
+# after an update, cache the current HEAD as the new baseline for next time
+python3 $S/scripts/scan.py --root . --state .claude/codemap/modules.json --stamp-rev
 # find modules to act on without reading the whole state (token-cheap, for agents)
 python3 $S/scripts/query.py --state .claude/codemap/modules.json --max-grade C --format ids
 python3 $S/scripts/query.py --state .claude/codemap/modules.json --tag dual-format

SKILL.md

@@ -130,8 +130,9 @@ Use when no `modules.json` exists yet.
    concurrency; chunk if needed).
 4. **Synthesize `reportThemes`** (4–7 cross-cutting patterns) from the collected findings
    and write them into `modules.json`.
-5. **Render:** run the render command. Report the result: avg score, grade spread, worst
-   offenders, and the two artifact paths.
+5. **Render:** run the render command. Then **stamp the git baseline** so future updates
+   can diff from here: `python3 scripts/scan.py --root <proj> --state <state> --stamp-rev`.
+   Report the result: avg score, grade spread, worst offenders, and the two artifact paths.
 
 ## Command: `check` (is the map current? — read-only)
 
@@ -140,24 +141,34 @@ Use when the user asks "is the architecture map up to date / still accurate?".
 1. `python3 scripts/scan.py --root <proj> --state <state>` (no `--write`).
 2. Read the JSON: report `up_to_date`, the **stale** list (code changed since audit),
    **unaudited** (new modules with no score), and **empty** (paths match nothing →
-   likely deleted modules). Do **not** modify anything. Tell the user exactly which
-   modules drifted and offer to run `update`.
+   likely deleted modules). The `git` block shows the **commits since the last codemap
+   run** (`meta.rev`) and which modules they touched — surface those commits so the user
+   sees recent history at a glance. Do **not** modify anything; offer to run `update`.
 3. Also sanity-check for *new* capabilities not yet in `modules.json` (a quick look at
    new top-level dirs / large new files). New modules are model-discovered, not scan-detected.
 
-## Command: `update` (incremental refresh)
+## Command: `update` (incremental refresh, git-aware)
 
-Use after code changes, or when `check` found drift. Only re-audits what changed.
+Use after code changes, or when `check` found drift. Re-audits only what changed, and
+uses git to show recent history and scope the work.
 
 1. **Reconcile structure first** (cheap): if modules were added/removed/renamed, edit
    `modules.json` (add new module entries with `paths`; drop `empty` ones; fix globs).
-2. `python3 scripts/scan.py --root <proj> --state <state> --write` → get `needs_audit`
-   (= stale + unaudited).
-3. **Re-audit only those modules**, each with its own independent subagent (same
-   protocol as `generate` step 3). Apply each via `apply_audit.py`. Fresh modules keep
-   their cached audit untouched — that is the whole point of the content hash.
+2. **Scan + git diff:** `python3 scripts/scan.py --root <proj> --state <state> --write`.
+   Read the report's **`git`** block: `commits` (since `meta.rev`, the last run) and
+   `changed_modules` (modules those commits touched). Show the user the recent commits —
+   this is the fast "what changed" view. The audit set is `needs_audit` (= stale +
+   unaudited); content-hash staleness already includes everything `changed_modules` lists
+   (plus any uncommitted edits), so re-audit `needs_audit`. If `git` is null the project
+   isn't a git repo — fall back to content-hash staleness only.
+3. **Re-audit only those modules**, each with its own independent subagent (same protocol
+   as `generate` step 3). Apply each via `apply_audit.py --id <id> --rev <head>`. Fresh
+   modules keep their cached audit — that is the whole point of the content hash.
 4. **Refresh `reportThemes`** if the changes are material (otherwise keep them).
-5. **Render.** Summarize what changed: which modules were re-scored and how their score moved.
+5. **Render**, then **stamp the baseline**:
+   `python3 scripts/scan.py --root <proj> --state <state> --stamp-rev` caches the current
+   HEAD into `meta.rev`, so the next `update`/`check` diffs from here. Summarize which
+   modules were re-scored and how their score moved, with the commits that caused it.
 
 ## Command: `test <module>` (generate tests)
 

reference/DATA_MODEL.md

@@ -13,7 +13,8 @@ subagents edit it) and re-render.
                                         //   should be authored in this language. ids/labels stay.
     "subtitle": "short tagline",        // optional header sub-line (write in meta.lang)
     "generatedAt": "2026-01-01",
-    "rev": "abc1234",                   // git rev these artifacts reflect (optional)
+    "rev": "abc1234",                   // git HEAD at the last codemap run (the baseline
+                                        //   `update`/`check` diff from; set by scan.py --stamp-rev)
     "htmlPath": "docs/architecture-map.html",  // for reciprocal links
     "mdPath": "docs/architecture-audit.md",
     "spineDesc": "A user edits … → … → persistence.",  // shown on the spine view

scripts/query.py

@@ -28,6 +28,10 @@ GRADE_BOUND = {"A": 101, "B": 90, "C": 75, "D": 60, "F": 40}
 
 
 def main():
+    try:
+        sys.stdout.reconfigure(encoding="utf-8")  # findings/descriptions may be non-ASCII
+    except (AttributeError, ValueError):
+        pass
     ap = argparse.ArgumentParser(description="filter modules.json for agents")
     ap.add_argument("--state", required=True)
     ap.add_argument("--max-grade", choices=list(GRADE_BOUND),

scripts/scan.py

@@ -15,10 +15,40 @@ declares `paths` (a list of globs, relative to the project root). This script:
         empty      — paths match no files (likely deleted / moved)
   * with --write, writes the fresh `loc` and `contentHash` back into the state.
 
+It also reports, when in a git repo, what changed since the last codemap run
+(`meta.rev`): the commits and which modules they touch — so `update` can show recent
+history at a glance and re-audit exactly the affected modules. `--stamp-rev` caches the
+current HEAD into `meta.rev` (run at the end of a successful update/generate).
+
 Output (stdout): a JSON report the orchestrator uses to decide what to re-audit.
 Stdlib only.
 """
-import argparse, glob, hashlib, json, os, sys
+import argparse, glob, hashlib, json, os, subprocess, sys
+
+
+def git(root, *args):
+    try:
+        r = subprocess.run(["git", "-C", root, *args],
+                           capture_output=True, text=True, timeout=15)
+        return r.stdout.strip() if r.returncode == 0 else None
+    except (OSError, subprocess.SubprocessError):
+        return None
+
+
+def git_changes_since(root, since):
+    """commits + changed files between `since` and HEAD, or None if unavailable."""
+    head = git(root, "rev-parse", "HEAD")
+    if not head:
+        return None  # not a git repo
+    info = {"head": head, "since": since}
+    if not since or git(root, "rev-parse", "--verify", "--quiet", since + "^{commit}") is None:
+        info["commits"], info["files"] = None, None   # no/unknown baseline → diff everything
+        return info
+    diff = git(root, "diff", "--name-only", since + "..HEAD") or ""
+    log = git(root, "log", "--pretty=format:%h %s", since + "..HEAD") or ""
+    info["files"] = [f for f in diff.splitlines() if f.strip()]
+    info["commits"] = [c for c in log.splitlines() if c.strip()]
+    return info
 
 DEFAULT_EXCLUDES = [
     # vcs / editor
@@ -74,11 +104,17 @@ def module_stats(root, module, excludes):
 
 
 def main():
+    try:
+        sys.stdout.reconfigure(encoding="utf-8")  # commit messages may be non-ASCII
+    except (AttributeError, ValueError):
+        pass
     ap = argparse.ArgumentParser()
     ap.add_argument("--root", default=".", help="project root")
     ap.add_argument("--state", required=True, help="path to modules.json")
     ap.add_argument("--write", action="store_true",
                     help="write fresh loc + contentHash back into the state")
+    ap.add_argument("--stamp-rev", action="store_true",
+                    help="cache current git HEAD into meta.rev (run at end of a successful update)")
     args = ap.parse_args()
 
     state = json.load(open(args.state, encoding="utf-8"))
@@ -87,6 +123,7 @@ def main():
 
     buckets = {"fresh": [], "stale": [], "unaudited": [], "empty": []}
     union_files = {}
+    file_index = {}  # repo-relative path -> [module ids] (for git-change → module mapping)
     for m in state.get("modules", []):
         loc, chash, nfiles = module_stats(root, m, excludes)
         m["loc"] = loc
@@ -95,6 +132,7 @@ def main():
         for p, rp in iter_files(root, (m.get("paths") or []),
                                 list(excludes) + list(m.get("exclude", []))):
             union_files[rp] = p
+            file_index.setdefault(rp, []).append(m["id"])
         if nfiles == 0:
             buckets["empty"].append(m["id"])
         elif not m.get("auditedHash") or m.get("score") is None:
@@ -112,7 +150,28 @@ def main():
         except OSError:
             pass
 
-    if args.write:
+    # git: what changed since the last codemap run (meta.rev)?
+    since = state.get("meta", {}).get("rev")
+    gc = git_changes_since(root, since)
+    git_report = None
+    changed_modules = []
+    if gc is not None:
+        if gc.get("files") is None:
+            git_report = {"head": gc["head"], "since": since,
+                          "note": "no/unknown baseline rev — treat all unaudited/stale as the change set"}
+        else:
+            for f in gc["files"]:
+                for mid in file_index.get(f, []):
+                    if mid not in changed_modules:
+                        changed_modules.append(mid)
+            git_report = {"head": gc["head"], "since": since,
+                          "commits": gc["commits"], "commit_count": len(gc["commits"]),
+                          "changed_files": len(gc["files"]),
+                          "changed_modules": sorted(changed_modules)}
+
+    if args.stamp_rev and gc and gc.get("head"):
+        state.setdefault("meta", {})["rev"] = gc["head"]
+    if args.write or args.stamp_rev:
         meta = state.setdefault("meta", {})
         meta["tracked_loc"] = tracked_loc
         meta["tracked_files"] = len(union_files)
@@ -127,6 +186,7 @@ def main():
         "needs_audit": needs,
         "needs_audit_count": len(needs),
         "up_to_date": len(needs) == 0 and not buckets["empty"],
+        "git": git_report,
         **buckets,
     }
     print(json.dumps(report, ensure_ascii=False, indent=1))