The inventory called this "no duplicate-content / cannibalisation detection".
Splitting that into its two halves shows one is free and the other is a trap.
CANNIBALISATION — free, and the data was already reachable. Search Analytics
has always accepted several dimensions at once ("no limit to the number of
dimensions that you can group by"); this engine only ever sent
`"dimensions": [dim]` and _norm_queries only ever read `keys[0]`. So
query+page — the pairing that exposes the conflict — was one parameter away
and nobody asked. Same shape of win as W1.
fetch.sh cannibal → queries where 2+ of OUR pages compete, ranked by total
impressions, strongest page first inside each. Same auth, same quota family,
no new scope. `capped` reports a full row window rather than presenting a
truncated list as exhaustive — same rule as COVERAGE and the sitemap caps.
Grouping happens in the engine, deterministically: asking an LLM to group
1000 rows by query is arithmetic it should never be handed.
Backward compatible: rows gained `keys` (the list the API actually returns);
`key` stays as keys[0], so the single-dim quick-wins consumer is untouched.
A test pins both.
30/70 DUPLICATION — deliberately NOT built, and this is the honest half.
Measuring it needs main-content extraction (strip nav/header/footer). Without
that, comparing two same-template pages returns ~95% similar for every site —
a confident false positive, which is exactly the failure class the rest of
this branch exists to remove. It stays an explicit LLM judgement over the >=3
same-family pages C1c now samples for it, labelled as judgement, never quoting
a similarity percentage nobody computed. A wrong number would be worse than
the current honest gap.
The two must not be merged in the report either: cannibalisation is a SERP
fact Google measured; 30/70 is a content question. The spec now says so.
Verified: fixture with 3 pages on one query, 2 on another, 1 on a third →
2 conflicts, correct ranking, single-page query excluded; live dispatch
degrades cleanly with no account; seo-data 110 -> 119 pass, 0 fail; full suite
green; shellcheck + py_compile clean.
seo-data — GSC + CrUX data layer for /seo FULL audits
Small, isolated engine that gives the /seo skill real Google data instead of
guesses: Search Console (queries, positions, indexation) and CrUX
(Core Web Vitals field data — real users, not lab simulation). It knows
nothing about SEO scoring; it only turns Google APIs into normalized JSON.
The seo-analyzer agent consumes that JSON in STEP 4 (Core Web Vitals) and
the new "Performance GSC" subsection; the /seo skill selects the account
and property in STEP 0 of a FULL audit (not needed for LOCAL).
Multi-account by design: the token store is keyed by a user-chosen label, and
every call takes --account/--property explicitly. Two audits running at
the same time (two sites, two sessions) never share mutable state — nothing
is written to disk during an audit, only at make seo-connect.
Setup
One-time per Google account:
make seo-connect # from the claude-config repo
bash ~/.claude/lib/seo-data/connect.sh --label <label> # from ANY directory (venv must exist)
make seo-connect creates ~/.claude/.venv-seo-data/ (isolated venv, deps
pinned in requirements.txt), installs google-auth,
google-auth-oauthlib, requests, then delegates to connect.sh. The
wrapper sources ~/.claude/.env internally, prefers the venv python, and
runs connect.py: it opens a browser for OAuth consent and takes a
label (e.g. client-a) to key the account — pick a name, not an email,
since the store never stores or requests the account's email. Once the venv
exists, connect.sh alone connects further accounts from anywhere (the
/seo connect [label] skill verb uses exactly this path).
Before running it, set these 3 keys in ~/.claude/.env (the canonical
vault; link.sh only symlinks the repo's .env to it and warns with a
cp .env.example .env hint if it's missing — it never creates the vault
itself):
GOOGLE_OAUTH_CLIENT_ID=<your-client-id>.apps.googleusercontent.com
GOOGLE_OAUTH_CLIENT_SECRET=<your-client-secret>
CRUX_API_KEY=<your-crux-api-key>
GOOGLE_OAUTH_CLIENT_ID/GOOGLE_OAUTH_CLIENT_SECRET— OAuth2 "Desktop app" credentials from the Google Cloud Console (APIs & Services → Credentials). Shared across every account you connect; the OAuth scope requested ishttps://www.googleapis.com/auth/webmasters.readonlyonly — read-only Search Console, nothing can be modified or deleted via this token.CRUX_API_KEY— a Chrome UX Report API key (restrict it to CrUX + PageSpeed in the Console). Get one at https://developer.chrome.com/docs/crux/api. No OAuth involved: CrUX is public field data, gated by API key only, independent of any connected account.
make seo-connect is idempotent and rerunnable — connecting a second
account just runs it again with a different label; reusing an existing
label prompts to overwrite.
fetch.sh contract
lib/seo-data/fetch.sh is the one stable entrypoint analyzers call. It
sources ~/.claude/.env, prefers the isolated venv (falls back to system
python3 for stdlib-only paths), dispatches to google_seo.py or
tokenstore.py, and never prints a secret to stdout or stderr.
fetch.sh accounts
→ {"status":"ok","accounts":[{"label":"…","properties":[…],"granted_at":"…"}]} # [] if none connected
fetch.sh crux --url https://ex.com [--strategy mobile|desktop]
→ {"status":"ok","source":"crux","lcp_p75_ms":…,"inp_p75_ms":…,"cls_p75":…} # a missing metric omits its key
→ {"status":"degraded","reason":"no_crux_key"|"no_field_data"|"rate_limited"}
# a 404 on page-level data retries at origin-level before degrading
fetch.sh queries --account client-a --property sc-domain:ex.com [--days 90] [--dim query|page]
→ {"status":"ok","source":"gsc","dimension":"query","rows":[{"key":"…","clicks":…,"impressions":…,"ctr":…,"position":…}]}
→ {"status":"degraded","reason":"no_credentials"|"token_revoked"|"network_error"|"rate_limited"}
fetch.sh inspect --account client-a --property … --url https://ex.com/page
→ {"status":"ok","source":"gsc","indexed":true,"coverage":"…","last_crawl":"…",
"rich_results":{"verdict":"PASS|FAIL|NEUTRAL|VERDICT_UNSPECIFIED|ABSENT",
"types":[{"type":"FAQ","items":2,"errors":2,"warnings":1,
"issues":["Missing field 'acceptedAnswer'"]}]}}
→ {"status":"degraded","reason":"…"}
rich_results rides the SAME URL-Inspection response — Google already sends
it, `inspect` used to discard it. No extra call, quota or OAuth scope.
It is the only programmatic structured-data validation in the system.
• verdict PARTIAL is never emitted — the API reserves it as unused.
• verdict ABSENT is SYNTHETIC (not a Google enum): the API omits
richResultsResult entirely when it detects no rich results. Surfaced
as a value rather than a missing key, because a caller cannot tell an
absent key apart from a check that never ran. ABSENT = "none
detected", never "invalid".
• errors/warnings count issue INSTANCES; issues[] is deduped — the same
issueMessage repeats across every affected item.
fetch.sh cannibal --account client-a --property … [--days 90] [--rows 1000]
→ {"status":"ok","source":"gsc","days":90,"rows_scanned":1000,"capped":true,
"conflict_count":12,
"conflicts":[{"query":"plombier paris","pages":3,"total_impressions":2400,
"urls":[{"url":…,"clicks":…,"impressions":…,"position":…}]}]}
→ {"status":"degraded","reason":"…"} # no account → NOT auditable
Keyword cannibalisation from Google's own data: queries where 2+ of OUR
pages compete. Groups query+page rows; conflicts ranked by total
impressions, and within each the strongest page first. `capped:true` means
the row window was full — more conflicts exist past the cut, say so.
Same auth, same quota family, no new scope: the API always accepted several
dimensions at once, this engine only ever asked for one.
• NOT the 30/70 duplication rule. This is a SERP fact Google measured.
30/70 is content similarity, which has no data source here — doing it
naively (compare two same-template pages without stripping nav/footer)
returns ~95% similar for every site, a confident false positive. It stays
an LLM judgement, labelled as one.
• `queries` now takes `--dim query,page` (comma-separated) and `--rows`.
Rows gained a `keys` list; `key` stays as keys[0], so the single-dim
consumer is untouched.
fetch.sh sitemap --url https://ex.com/sitemap.xml
→ {"status":"ok","source":"sitemap","index":false,"count":86,"dropped":0,
"urls":["https://ex.com/", …]}
→ {"status":"ok","index":true,"children_total":4,"children_read":4,
"children_failed":0,"count":312,…} # <sitemapindex>, one level deep
→ {"status":"degraded","reason":"fetch_failed"|"parse_failed"|"no_urls"
|"unsafe_xml_dtd"}
No auth, no Google, no venv: stdlib only (urllib + xml.etree + gzip).
Gives STEP 9's COVERAGE line the denominator it was told to print and never
had, and STEP 5 a real sampling frame. Dedupes, strips whitespace, handles
.xml.gz. Caps: 50 children of an index, 50k URLs, 20 MB read — each cut is
REPORTED (children_skipped / truncated), never silent.
• NOT a security boundary. urllib fetches these, so nothing here reaches a
shell. The CONSUMER interpolates them into curl, so seo-analyzer runs
lib/url-guard.sh at the point of use — same contract as the sameAs check.
A second copy of the guard here would only drift.
• `unsafe_xml_dtd`: a sitemap NEVER has a DTD (sitemaps.org is <?xml?> then
<urlset xmlns=>). Any doctype/entity is refused BEFORE parsing. xml.etree
does not expand external entities, but it IS billion-laughs-vulnerable —
1 KB expands to gigabytes, and the 20 MB read ceiling bounds the input,
not the expansion. Refusing the construct beats depending on parser
internals AND keeps this stdlib-only; defusedxml would drag in a venv for
a document type that has no legitimate DTD.
fetch.sh forget --label client-a
→ {"status":"ok","removed":true|false} # false = label wasn't in the store
fetch.sh forget --all
→ {"status":"ok","cleared":<n>} # n = accounts removed
Rules that hold for every subcommand:
- JSON always on stdout, never empty. Even an unexpected error (HTTP
403/5xx, timeout, DNS failure) prints
{"status":"degraded","reason":"unexpected_error"}— never a raw traceback. statusis"ok"or"degraded"on exit 0;"error"on exit 2. Analyzers branch on this field;"error"only shows up on bad usage,reasonis informational otherwise.- Exit code 0 on
okand ondegraded. The engine never fails the process just because Google data isn't available — that's a normal, expected outcome the analyzer handles by falling back. Exit code 2 is reserved for bad usage: unknown subcommand, missing required flag, invalid argument — those paths emit{"status":"error",...}instead. --storeis accepted uniformly by every subcommand for consistentfetch.shdispatch, even thoughcruxignores it (CrUX needs no account).- Never prints a secret. No env var, refresh token, or access token ever reaches stdout or stderr, including in error paths.
Two env vars exist for testing, never for normal use:
SEO_DATA_ENV_FILE overrides which env file is sourced (tests point it at
/dev/null so a real ~/.claude/.env on the machine can never leak into a
test run), and SEO_DATA_DEBUG=1 re-enables stderr for local debugging
(stderr is suppressed by default so library warnings can't leak a secret
into an agent's context).
Token store
~/.claude/seo-data/tokens.json — refresh tokens, keyed by the label chosen
at make seo-connect, one entry per connected account:
{
"version": 1,
"accounts": {
"client-a": {
"refresh_token": "<opaque>",
"scopes": ["https://www.googleapis.com/auth/webmasters.readonly"],
"granted_at": "2026-07-09T12:00:00+00:00",
"properties": ["sc-domain:site-a.com", "https://www.site-a.com/"]
}
}
}
Security posture:
- File
0600, directory0700.tokenstore.save_accountre-asserts both permissions on every write. - Written only at
connecttime, atomically.tmp→fsync→os.replace(atomic rename), under an exclusivefcntllock, so two simultaneousmake seo-connectruns can't corrupt the file. Audits never write to this file — access tokens are exchanged in memory and never persisted, so two audits running concurrently never contend on it. - Keyed by label, not email. Identifying accounts by email would
require widening the OAuth scope just for identification; the label the
user picks at connect time is sufficient and keeps the scope at
webmasters.readonlyonly (least privilege). - Refresh tokens are redacted from
list.fetch.sh accounts(andtokenstore.py list) return label, properties, andgranted_atonly — therefresh_tokenfield is intentionally never included in that output. - Allowlisted in gitleaks. The store lives under
~/.claude/, outside this repo, so it's never committed directly — butmake scan-secretsalso sweeps~/.claudefor stray copies of secrets..gitleaks.tomlhas an explicit[allowlist].pathsentry for(^|/)\.claude/seo-data/tokens\.json$, the same treatment~/.claude/.envalready gets, so a legitimate local secret store doesn't drown real findings in false positives. - Also gitignored (
.venv-seo-data/andseo-data/tokens.jsonin.gitignore) as a second, belt-and-suspenders guard in case a relative path ever put either under the repo tree. - Removal is local-only.
fetch.sh forget --label <x>/--all(the/seo forgetskill verb) deletes the stored refresh token — it does NOT revoke the OAuth grant at Google's end. For a real revocation, visit https://myaccount.google.com/permissions with the account concerned and remove the app's access; the deleted local token then becomes useless everywhere, including to anyone who copied it beforehand.
Graceful degradation
Missing API key, no connected account, or a revoked/expired token is a normal outcome, not a failure:
- No
CRUX_API_KEY→cruxreturns{"status":"degraded","reason":"no_crux_key"}. - No account connected, or the store has no refresh token for the given
--account→queries/inspectreturn{"status":"degraded","reason":"no_credentials"}. - Refresh token revoked at Google's end →
{"status":"degraded","reason":"token_revoked"}(a transient network blip during refresh is classified"network_error"instead, so a flaky connection never forces the user back through OAuth). - Rate limited (HTTP 429) on any Google API →
{"status":"degraded","reason":"rate_limited"}.
In every case: exit code 0, valid JSON on stdout, no crash. The /seo
FULL audit continues on the anonymous PageSpeed API (lab data) instead of
CrUX field data, and the report surfaces the fix as a user action:
make seo-connect. doctor.sh also flags both non-fatally as WARN: a
missing CRUX_API_KEY warns on its own, while no connected Google account
is the one that names make seo-connect.
Testing
make test
# or, to run only this engine's suite:
bash lib/seo-data/seo-data.test.sh
The suite is network-free: google_seo.py reads fixtures from
lib/seo-data/fixtures/ (crux_mobile.json, gsc_queries.json,
gsc_inspect.json) whenever SEO_DATA_MOCK_DIR is set, instead of calling
Google's APIs. Degradation paths run with real env vars unset (env -u CRUX_API_KEY, env -u SEO_DATA_MOCK_DIR) to exercise the no-key/no-creds
branches deterministically. Every fetch.sh invocation in the tests also
sets SEO_DATA_ENV_FILE=/dev/null so a machine with a live
~/.claude/.env never lets real credentials leak into a test run.