diff --git a/docs/superpowers/plans/2026-05-20-openid-scope-fix.md b/docs/superpowers/plans/2026-05-20-openid-scope-fix.md
new file mode 100644
index 0000000..1dc9c0b
--- /dev/null
+++ b/docs/superpowers/plans/2026-05-20-openid-scope-fix.md
@@ -0,0 +1,147 @@
+# Add `openid` to OAuth SCOPES Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Append `"openid"` to `SCOPES` in `src/multi_google_mcp/config.py` so `oauthlib` stops aborting `multi-google-mcp-auth add` when Google implicitly grants the `openid` scope.
+
+**Architecture:** One-line edit to a config list. No new tests (the OAuth flow is not exercised in the test suite; verification happens against live Google APIs). After editing, the locally installed `multi-google-mcp-auth` console script is reinstalled with `uv tool install --reinstall .` so it picks up the new code, then the auth flow is driven manually against the `personal` account to confirm the fix.
+
+**Tech Stack:** Python 3.11+, `uv`, `google-auth-oauthlib`, `oauthlib`, `mcp` SDK.
+
+---
+
+## File Structure
+
+- Modify: `src/multi_google_mcp/config.py:9-14` — add `"openid"` to the existing `SCOPES` list.
+
+That's all. No new files, no other modifications.
+
+---
+
+### Task 1: Add `openid` to SCOPES and verify static checks
+
+**Files:**
+- Modify: `src/multi_google_mcp/config.py:9-14`
+
+- [ ] **Step 1: Make the edit**
+
+Open `src/multi_google_mcp/config.py` and change the `SCOPES` list from:
+
+```python
+SCOPES = [
+    "https://www.googleapis.com/auth/gmail.modify",
+    "https://www.googleapis.com/auth/calendar",
+    "https://www.googleapis.com/auth/drive",
+    "https://www.googleapis.com/auth/userinfo.email",
+]
+```
+
+to:
+
+```python
+SCOPES = [
+    "https://www.googleapis.com/auth/gmail.modify",
+    "https://www.googleapis.com/auth/calendar",
+    "https://www.googleapis.com/auth/drive",
+    "https://www.googleapis.com/auth/userinfo.email",
+    "openid",
+]
+```
+
+- [ ] **Step 2: Run the existing test suite**
+
+Run: `uv run pytest`
+Expected: PASS — all existing tests still pass. The added scope is consumed only by the auth CLI's `InstalledAppFlow` and is not exercised in tests (`accounts.py` references `config.SCOPES` but the test fixtures stub out the OAuth flow entirely).
+
+- [ ] **Step 3: Run the linter**
+
+Run: `uv run ruff check .`
+Expected: PASS — `All checks passed!`.
+
+- [ ] **Step 4: Run the type-checker**
+
+Run: `uv run mypy`
+Expected: PASS — no new errors.
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add src/multi_google_mcp/config.py
+git commit -m "$(cat <<'EOF'
+fix: add openid to OAuth SCOPES to unblock auth flow
+
+Google implicitly grants the openid scope whenever userinfo.email (or
+any identity-bearing scope) is requested. oauthlib raises the scope
+mismatch as an exception via its Warning-to-error path, aborting
+multi-google-mcp-auth add before any token is written.
+
+Adding "openid" to the requested set keeps the granted set aligned and
+silences oauthlib without changing actual API access.
+
+Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
+EOF
+)"
+```
+
+---
+
+### Task 2: Reinstall the console scripts so the installed CLI picks up the new code
+
+**Files:** None modified.
+
+- [ ] **Step 1: Reinstall**
+
+Run: `uv tool install --reinstall .`
+Expected: output ends with something like `Installed 2 executables: multi-google-mcp, multi-google-mcp-auth`. No errors.
+
+- [ ] **Step 2: Sanity-check the installed binary picks up the new scope list**
+
+Run:
+```bash
+which multi-google-mcp-auth
+uv tool run --from . python -c "from multi_google_mcp.config import SCOPES; print('openid' in SCOPES, len(SCOPES))"
+```
+Expected: path is printed; second line prints `True 5`.
+
+- [ ] **Step 3: No commit**
+
+Reinstall produces no repo changes — nothing to commit.
+
+---
+
+### Task 3: Verify the fix end-to-end against the `personal` account
+
+**Files:** None modified.
+
+- [ ] **Step 1: Run the auth flow**
+
+Run: `multi-google-mcp-auth add personal`
+Expected behavior:
+- Prints a `Please visit this URL` line and opens a browser tab to Google's consent screen.
+- User completes consent in the browser.
+- Process prints something like `Saved account 'personal' to ~/.config/multi-google-mcp/accounts/personal.json` (or whatever success line `auth_cli.py` emits) and exits 0.
+- The previous failure mode — an `oauthlib` exception about scope mismatch / Warning before the token file is written — does NOT occur.
+
+Note: this step is interactive (browser OAuth consent). If running in a non-interactive context, hand off to the user with a clear "please complete the OAuth consent in your browser" prompt.
+
+- [ ] **Step 2: Confirm the token file was (re)written**
+
+Run: `ls -la ~/.config/multi-google-mcp/accounts/personal.json && stat -f '%Sm' ~/.config/multi-google-mcp/accounts/personal.json`
+Expected: file exists, permissions are `-rw-------` (mode 0o600 per `accounts._atomic_write_json`), modification timestamp is from the last few seconds.
+
+- [ ] **Step 3: Confirm the new scope set is in the saved token**
+
+Run: `python -c "import json; d=json.load(open('${HOME}/.config/multi-google-mcp/accounts/personal.json')); print(sorted(d.get('scopes', [])))"`
+Expected: list includes `"openid"` alongside the other four scopes.
+
+- [ ] **Step 4: No commit**
+
+Verification produces no repo changes — nothing to commit.
+
+---
+
+## Notes on what is *not* in this plan
+
+- No new unit test. The `SCOPES` list is data, not behavior; the OAuth flow it feeds is not under test in this repo (test fixtures mock `googleapiclient.discovery.build` and never construct an `InstalledAppFlow`). Per the test-driven-development skill's config-only exception, no test is added.
+- No update to CLAUDE.md's commentary about the SCOPES list — out of scope for this fix.
+- No revisit of other OAuth-flow ergonomics (token rotation, scope subset upgrades, etc.).
diff --git a/docs/superpowers/specs/2026-05-20-openid-scope-fix-design.md b/docs/superpowers/specs/2026-05-20-openid-scope-fix-design.md
new file mode 100644
index 0000000..df7f392
--- /dev/null
+++ b/docs/superpowers/specs/2026-05-20-openid-scope-fix-design.md
@@ -0,0 +1,68 @@
+# Add `openid` to OAuth SCOPES to unblock auth flow
+
+## Goal
+
+Fix `multi-google-mcp-auth add <label>` aborting when Google returns `openid` in
+the granted scope set. Add `"openid"` to `config.SCOPES` so the requested set
+matches what Google returns, and `oauthlib`'s scope-change check stops firing.
+
+## Background
+
+Google's OAuth implementation implicitly grants `openid` whenever
+`userinfo.email` (or other identity-bearing scopes) is requested. `oauthlib`'s
+`InstalledAppFlow` treats any divergence between requested and granted scopes as
+a `Warning`, which `oauthlib` raises as an exception, aborting the flow before
+the token is persisted. The repro is `multi-google-mcp-auth add personal`
+against a fresh OAuth client — it fails consistently.
+
+## Change
+
+Single-line edit to `src/multi_google_mcp/config.py`: append `"openid"` to the
+`SCOPES` list.
+
+```python
+SCOPES = [
+    "https://www.googleapis.com/auth/gmail.modify",
+    "https://www.googleapis.com/auth/calendar",
+    "https://www.googleapis.com/auth/drive",
+    "https://www.googleapis.com/auth/userinfo.email",
+    "openid",
+]
+```
+
+No code changes elsewhere. `accounts.py` consumes `SCOPES` directly from
+`config`; nothing else cares about the list contents.
+
+## Why not a test
+
+The OAuth flow only runs against live Google APIs — `auth_cli.py` calls
+`google_auth_oauthlib.flow.InstalledAppFlow.from_client_secrets_file(...)` and
+drives a local browser callback. The existing test suite mocks
+`googleapiclient.discovery.build` and never exercises the auth flow. There is no
+seam for a unit test to catch this regression, and the scope-list contents are
+trivially inspectable. Per the `superpowers:test-driven-development` config-only
+exception, no new test is added.
+
+## Verification
+
+1. `uv tool install --reinstall .` — reinstall the console script so the
+   already-installed `multi-google-mcp-auth` picks up the updated `SCOPES`.
+2. `multi-google-mcp-auth add personal` — completes without `oauthlib` raising
+   on scope mismatch, prints success, writes
+   `~/.config/multi-google-mcp/accounts/personal.json`.
+
+## Caveats
+
+- CLAUDE.md notes: changing `SCOPES` requires every existing account to be
+  re-added. The `personal` account is re-added as the verify step. No other
+  accounts exist locally (confirmed by user), so nothing else to handle.
+- This is a one-way fix — `openid` is a stable, standardized OIDC scope and is
+  effectively always granted alongside `userinfo.email`. No regression risk for
+  callers that don't care about identity tokens (we don't use the ID token; the
+  scope is purely there to keep `oauthlib` quiet).
+
+## Non-goals
+
+- No update to CLAUDE.md's scope-list commentary in this change.
+- No revisit of the broader OAuth flow or scope set.
+- No swap to a different OAuth library or relaxed `oauthlib` warning policy.
diff --git a/src/multi_google_mcp/config.py b/src/multi_google_mcp/config.py
index a756351..ea65585 100644
--- a/src/multi_google_mcp/config.py
+++ b/src/multi_google_mcp/config.py
@@ -11,6 +11,7 @@
     "https://www.googleapis.com/auth/calendar",
     "https://www.googleapis.com/auth/drive",
     "https://www.googleapis.com/auth/userinfo.email",
+    "openid",
 ]
 
 # Cap on Drive payload size (read or upload) so a 1 GB PDF can't hang the MCP