Google Merchant Center MCP (gmc-mcp)

MCP server for Google Merchant Center, built on Merchant API v1. 126 tools, MIT-licensed, pip install-able. Drive your Google Shopping feed, products, inventory, Reports, promotions, returns, and account configuration in natural language from Claude Desktop, Claude Code, or any MCP-compatible client.

Where this fits in the GMC + MCP landscape

Option	Type	API	License	Install	Tools
Adzviser / Catchr / Windsor.ai / Pipedream	Paid hosted SaaS	varies	proprietary	sign-up	varies
archpeng/GMC-mcp-server	Self-hosted	Content API v2.1 (deprecated 2026-08)	none declared	git clone	34
gmc-mcp (this package)	Self-hosted	Merchant API v1 (future-proof)	MIT	pip install gmc-mcp	126

Pick this if you want: future-proof API, an actual OSS license, PyPI install, a larger toolset, audit log + rollback + dry-run safety, and credentials that never leave your machine.

Built on Merchant API v1 (replaces Content API for Shopping; v1beta was discontinued 2026-02-28). Safe by default: every write is recorded to an append-only audit log with before snapshots, dry-run is one toggle away, and destructive bulk operations require an explicit confirm parameter.

Why this exists

Google Merchant Center (GMC) powers Google Shopping listings, Free Listings, Shopping Ads, Buy on Google checkout, YouTube Shopping, and more. Managing a feed of thousands of products through the GMC web UI is tedious, and writing one-off Python scripts against the Merchant API REST endpoints is slow.

There are existing MCP services for GMC, but they fit different niches:

• Paid hosted SaaS (Adzviser, Catchr, Windsor.ai, Pipedream) — your data is proxied through their servers; monthly subscription.
• archpeng/GMC-mcp-server — earliest self-hosted Python option (Feb 2026), but built on the deprecated Content API v2.1 which Google retires in August 2026, has no license declared, and isn't on PyPI.

gmc-mcp was built to fill the gap: a self-hosted package on the new Merchant API v1, MIT-licensed, on PyPI, with audit/rollback/dry-run safety and 126 tools across 19 modules.

The package gives Claude (or any MCP client) 126 tools that map directly onto the Merchant API v1 surface, so you can do things like:

• "Show me every disapproved product, grouped by issue code."
• "Bump US prices 5% on these 40 SKUs."
• "Which products had impressions but zero clicks last week?"
• "Roll back audit ID 8fc8dc42… — that update broke something."
• "Compare this Shopify CSV against my GMC feed; what's missing?"

What's exposed

126 tools across 19 modules + 4 meta tools.

CLI also exposes: gmc-mcp run, auth-init, register-gcp, webhook, describe, version.

Install

pip install gmc-mcp

For development:

git clone https://github.com/kiwoongeom/gmc-mcp
cd gmc-mcp
pip install -e ".[dev,test]"
pre-commit install

Quick start

1. Enable the Merchant API and create a service account

1. console.cloud.google.com → create / pick a project.
2. APIs & Services → Library → enable Merchant API.
3. IAM & Admin → Service Accounts → Create service account named gmc-mcp.
4. Open the new service account → Keys → Add key → Create new key → JSON. Save it somewhere safe.

2. Add the service account to your Merchant Center

1. merchants.google.com → top-right gear → Account access → People.
2. Add user → enter the gmc-mcp@PROJECT.iam.gserviceaccount.com email → grant Admin.
3. Note the 10-digit Merchant Center ID in the top-right.

3. Configure

cp .env.example .env
# edit:
#   GMC_ACCOUNT_ID=1234567890
#   GMC_SERVICE_ACCOUNT_KEY=/abs/path/to/service-account.json

4. One-time GCP registration

Required before any v1 Merchant API call works for a new project.

gmc-mcp register-gcp --developer-email you@example.com

5. Smoke-test

gmc-mcp describe              # prints the resolved config
python examples/quickstart.py  # makes one read against the Merchant API

6. Wire into Claude

Drop this into %APPDATA%/Claude/claude_desktop_config.json (Desktop) or ~/.claude/settings.json (Code):

{
  "mcpServers": {
    "gmc": {
      "command": "gmc-mcp",
      "args": ["run"],
      "env": {
        "GMC_ACCOUNT_ID": "1234567890",
        "GMC_SERVICE_ACCOUNT_KEY": "/abs/path/to/service-account.json"
      }
    }
  }
}

Restart Claude. Ask: "What account am I connected to?" — it should call gmc_describe_server.

OAuth instead of a service account

For acting on behalf of an end user (e.g. multi-tenant SaaS):

# 1. In GCP, create OAuth client credentials (type: Desktop), download client_secret.json.
gmc-mcp auth-init --client-secrets ./client_secret.json
# follow the browser flow; a token JSON is saved to secrets/oauth-token.json.

# 2. Use it
export GMC_OAUTH_TOKEN=./secrets/oauth-token.json
gmc-mcp run

Transports

gmc-mcp run                              # stdio (Claude Desktop default)
gmc-mcp run --transport sse --port 8000  # SSE / HTTP (remote, Docker, hosted)

Or via Docker:

docker build -t gmc-mcp .
docker run --rm -p 8000:8000 \
    -e GMC_ACCOUNT_ID=1234567890 \
    -v $PWD/secrets:/secrets \
    -e GMC_SERVICE_ACCOUNT_KEY=/secrets/service-account.json \
    gmc-mcp

Audit log + rollback

Every write logs a JSONL entry to GMC_AUDIT_LOG (default: ./logs/audit.jsonl). Each entry contains:

• audit_id — UUID for lookup
• op, method, url, request_body, response_status, response_body
• before — pre-write snapshot when the tool fetched it (used by update_* and delete_*)
• dry_run — whether the request was actually sent

Inspect from inside Claude:

> Show me my last 5 GMC writes.
[gmc_audit_tail(limit=5) → ...]

> Look up audit ID abc123.
[gmc_audit_lookup(audit_id="abc123") → ...]

> Roll back audit ID abc123, that update was wrong.
[gmc_rollback(audit_id="abc123", confirm="ROLLBACK") → ...]

Dry-run

Two ways to enable:

GMC_DRY_RUN=true gmc-mcp run

> Set dry-run on and update the price of SKU1 to $19.99.
[gmc_set_dry_run(enabled=True) → ok]
[gmc_update_regional_inventory(...) → {"_dry_run": true, ...}]

Reads always go through; only writes are skipped.

Reports query examples

Paste into gmc_query_report:

-- Top 50 by clicks last 7 days
SELECT offer_id, title, clicks, impressions, ctr
FROM product_performance_view
WHERE date BETWEEN '2026-04-23' AND '2026-04-30'
ORDER BY clicks DESC LIMIT 50

-- Disapproved products with reason codes
SELECT id, offer_id, title, item_issues
FROM product_view
WHERE aggregated_reporting_context_status = 'NOT_ELIGIBLE_OR_DISAPPROVED'

-- You're priced higher than the benchmark
SELECT offer_id, title, price, benchmark_price
FROM price_competitiveness_product_view
WHERE price > benchmark_price LIMIT 100

Configuration reference

All config is via env vars (or .env). CLI flags --transport, --host, --port, --env override.

Architecture

Claude (any MCP client)
    │  JSON-RPC over stdio or SSE
    ▼
gmc-mcp server  ──►  audit.jsonl
    │
    │  HTTP + Bearer token
    ▼
merchantapi.googleapis.com  ──►  Google Merchant Center

• auth.py — ServiceAccountAuth and OAuthUserAuth share an Auth protocol.
• client.py — single MerchantClient with retries (5x w/ jitter), pagination helper, and write-audit hook.
• tools/*.py — each module exposes a register(mcp, client) that registers @mcp.tool() functions.
• audit.py — append-only JSONL, lookup by ID, supports before snapshots.
• cli.py — gmc-mcp run | auth-init | register-gcp | webhook | describe | version.

Testing

pytest                       # 100% offline; uses respx to mock HTTP
pytest --cov=gmc_mcp         # with coverage
ruff check src tests
mypy src/gmc_mcp

Roadmap

• v0.3: webhook handler scaffolding (auto-respond to gmc_subscribe callbacks)
• v0.3: native Merchant API v1 GA migration when Google releases it
• v0.4: BigQuery export of Reports queries
• v0.4: rule-based auto-fixers ("on disapproval, retry with corrected attribute")

Contributing

See CONTRIBUTING.md. PRs and issues welcome — this is the first open-source MCP for Google Merchant Center, so there's a lot of room for community input on which workflows deserve dedicated tools.

License

MIT — see LICENSE.

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