diff --git a/CLAUDE.md b/CLAUDE.md
index 70bc10d..2986d5c 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -5,8 +5,8 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 ## Project status
 
 Two packages are merged to main and working:
-- `@gitmarks/core` (`packages/core/`) — schemas, GitHub Contents API client with optimistic concurrency, ULID/URL helpers, pure mutation helpers, example fixtures. 59 unit tests.
-- `@gitmarks/extension-chrome` (`packages/extension-chrome/`) — MV3 Chrome extension with toolbar save, two-way native-tree sync, 5-min poll, initial reconciliation. 53 unit tests + 6 Playwright e2e tests.
+- `@gitmarks/core` (`packages/core/`) — schemas, GitHub Contents API client with optimistic concurrency, ULID/URL helpers (incl. opt-in tracking-param stripping), pure mutation helpers, example fixtures. 65 unit tests.
+- `@gitmarks/extension-chrome` (`packages/extension-chrome/`) — MV3 Chrome extension with toolbar save, two-way native-tree sync, 5-min poll, initial reconciliation, opt-in tracking-param stripping settings flag. 97 unit tests + 4 Playwright e2e tests (2 e2e skipped pending Playwright limitation fixes — see issue history).
 
 Pending packages (in dependency order): Firefox build, web UI (read + search + tags), web UI (write + bulk ops), Safari.
 
@@ -35,7 +35,7 @@ These are spec-level constraints; don't violate without an explicit discussion:
 Pure TypeScript ESM library. No browser APIs, no React. Three layers:
 
 - **Schemas** (`src/schema/`): Zod schemas for `bookmarks.json` and `tags.json`. Inferred types (`Bookmark`, `BookmarksFile`, `Tag`, `TagsFile`).
-- **Primitives** (`src/url.ts`, `src/ulid.ts`): URL normalization (strip trailing slash, drop non-hashbang fragments) and ULID generation. Wrappers so call sites depend on `@gitmarks/core` not `ulid` directly.
+- **Primitives** (`src/url.ts`, `src/ulid.ts`): URL normalization (strip trailing slash, drop non-hashbang fragments, optionally strip utm_*/fbclid/gclid/msclkid/mc_* tracking params via `{ stripTrackingParams: true }`) and ULID generation. Wrappers so call sites depend on `@gitmarks/core` not `ulid` directly.
 - **Mutations** (`src/mutate.ts`): pure functions — `addBookmark`, `updateBookmark`, `softDeleteBookmark`, `gcTombstones`. Each takes a `BookmarksFile` and `nowIso`, returns a new file. **Purity is load-bearing** — `GitHubClient.update()` replays these on conflict, so they must not close over external state.
 - **GitHub client** (`src/github/client.ts`): `GitHubClient` class with `read`, `readIfChanged` (ETag-conditional), `write` (create or update), `update` (read → mutate → write with 409/422 replay). DI fetch in the constructor for testability — no `msw` needed.
 
diff --git a/README.md b/README.md
index 0ed80d5..4213f99 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,8 @@ the roadmap. See `spec.md` for the full design.
   on the next 5-minute poll
 - Concurrent edits from multiple devices reconcile automatically via
   GitHub's file SHA + optimistic retry-replay
-- 112 automated tests (unit + Playwright e2e against real Chromium)
+- 162 automated tests (unit + Playwright e2e against real Chromium)
+- Optional **tracking-param stripping** (utm_*, fbclid, gclid, etc.) at save time — opt-in via settings
 
 ## Packages
 
@@ -120,10 +121,11 @@ The load-bearing invariants:
 - ✅ `@gitmarks/core` — schemas, GitHub client, mutations
 - ✅ Chrome MVP — toolbar-button save flow
 - ✅ Chrome native tree integration — listeners, reconcile, poll loop
-- ⬜ Firefox build (`webextension-polyfill`)
-- ⬜ Web UI: list / search / tag management
-- ⬜ Web UI: bulk operations + trash + export
-- ⬜ Safari (via `safari-web-extension-converter`)
+- ✅ Tracking-param stripping (opt-in)
+- ⬜ Firefox build ([#23](https://github.com/paperhurts/gitmarks/issues/23))
+- ⬜ Web UI v1: list + search + tag management ([#24](https://github.com/paperhurts/gitmarks/issues/24))
+- ⬜ Web UI v2: bulk operations + trash + export ([#25](https://github.com/paperhurts/gitmarks/issues/25))
+- ⬜ Safari ([#26](https://github.com/paperhurts/gitmarks/issues/26))
 
 ## Files in this repo
 
diff --git a/packages/extension-chrome/README.md b/packages/extension-chrome/README.md
index 4f58cc4..8b1d12f 100644
--- a/packages/extension-chrome/README.md
+++ b/packages/extension-chrome/README.md
@@ -26,11 +26,15 @@ are deferred). Pin it for easy access.
    Read and write**.
 2. Click the toolbar icon → "Set up gitmarks" → enter PAT, owner, repo,
    branch.
-3. Click **Validate**. You should see either
+3. Optionally enable **"Strip tracking parameters"** to remove `utm_*`,
+   `fbclid`, `gclid`, `msclkid`, and `mc_*` from saved URLs. Default off
+   per the spec's open-question rationale (some sites use `utm_*` for
+   non-tracking purposes).
+4. Click **Validate**. You should see either
    "✓ valid PAT, repo exists, bookmarks.json found" or
    "✓ valid PAT, repo exists (bookmarks.json not yet created — will be on
    first save)".
-4. Click **Save**.
+5. Click **Save**.
 
 ## Manual smoke test