cypher-mcp
Monetized graph answers over Bitcoin Lightning. A Tollbooth-DPYC Operator
that sells priced answers from a graph — operator-authored, parameterized,
named Cypher query templates — not raw database access.
The OSS Neo4j MCP servers are a free pipe to a database the operator
separately expenses (Neo4j invoice) and separately bills for (Stripe stack).
cypher-mcp collapses infrastructure cost, application billing, and access
control into one metered MCP surface: the operator stops selling seats and
starts selling answers, settled in sats, with no Stripe stack and no Neo4j
invoice passed to the customer.
Live at https://cypher-mcp.fastmcp.app/mcp.
How it works
Two planes, cleanly separated:
- Settlement / identity plane — Neon + Nostr + Tollbooth, shared with
every other DPYC operator. It never knows a graph exists.
- Value-delivery plane — Bolt → Neo4j, sealed inside the tool handlers
(
graph.py), opened and torn down per request (no pool). The backing store
is an implementation detail invisible to patrons, so it can be swapped
without changing the MCP surface.
Three conceptual layers:
| Layer | Where | What |
|---|
| L1 — primitive | code (shipped once) | execute_query_by_key(key, params) + catalog CRUD |
| L2 — catalog | Neon query_catalog | key → vetted Cypher template + param schema (what's possible) |
| L3 — pricing | Tollbooth pricing model | what's sold, named, priced |
Status: live, with named tools. L1 + L2 are shipped and serving real,
billed answers — an operator adopted by an Authority, AuraDB-backed, with
refund-on-raise verified end to end. Named tools are now live (L3 tool
synthesis): an operator can publish_tool(key) to project a query as a
first-class, typed tool (e.g. cypher_find_airline_flights(from_city, to_city)), priced individually in Pricing Studio. Per-key parametric pricing
formulas remain a later step — see CHANGELOG.md.
Patron (priced):
cypher_execute_query_by_key(key, params) — run a published query. You
supply only parameters; the operator owns the query text, and parameters
bind as Cypher $params (never string-interpolated). You're charged only
for a delivered answer — an unknown key, invalid parameters, or a failed
query rolls back the debit (refund-on-raise).
Plus the standard DPYC surface from the wheel: cypher_check_balance,
cypher_check_price, cypher_purchase_credits, Secure Courier, npub proof,
Oracle delegation, account statements, constraint-based dynamic pricing, etc.
Operator-only (restricted, unpriced) — the authoring plane:
cypher_create_query / cypher_update_query / cypher_get_query /
cypher_list_queries / cypher_delete_querycypher_publish_tool(key) / cypher_unpublish_tool(key) — project a query as
a first-class, typed named tool (or retire it). See Named tools below.
Raw Cypher never reaches patrons — only named, parameterized templates.
Authoring in Neo4j's own UI — no second editor to learn
A DB-analyst refines templates in Neo4j Browser, not in a bespoke tool.
cypher_get_query(key) returns the template plus an edit_url — a deep
link into the hosted Neo4j Browser (browser.neo4j.io) that pre-targets the
operator's AuraDB and loads the statement in edit mode (cmd=edit).
Refine it with autocomplete, run-to-test, visualization, and PROFILE; then
save it back with cypher_update_query. The template is just a string flowing
over MCP — no files, no desktop, no exported bundles. The link carries the
DBMS URI but never the password, and get_query is operator-only, so neither
ever reaches a patron.
cypher_publish_tool(key) projects a catalog query as a first-class MCP tool
named cypher_<key> whose flat, typed parameters come from the query's schema —
e.g. cypher_find_airline_flights(from_city, to_city). An agent then calls it by
name with typed params instead of execute_query_by_key(key, params). Internally
every named tool funnels through the same shared executor (look the stored
Cypher up by key → parameter-bind → run), so there is one code path and the same
refund-on-raise guarantee. A published tool registers unpriced — it appears in
Pricing Studio like any new tool; set its price there (calls return "not priced yet
(TBD)" until you do). cypher_unpublish_tool(key) retires the tool (the query
itself stays, still runnable by key). Published tools survive restarts
(re-materialized from the catalog); reconnect to observe tool-list changes.
The synthesis machinery is a generic tollbooth-dpyc primitive
(register_dynamic_tool) — named Cypher queries are one realization; the same
primitive can back a synthesized tool with a REST call, SQL, or a stored prompt.
Onboarding (operator)
- Request adoption from an Authority (the deferred courtship —
request_adoption) or be registered directly. Either way the Authority
provisions an isolated Neon tenant automatically.
- Deliver operator secrets via Secure Courier
(
cypher_request_credential_channel, service cypher-operator):
neo4j_uri, neo4j_user, neo4j_password — the graph store
(e.g. a Neo4j AuraDB instance)btcpay_host, btcpay_api_key, btcpay_store_id — Lightning
- Author your catalog with
cypher_create_query; patrons then execute by key.
Develop
pip install -e ".[dev]"
pytest -v
python -m cypher_mcp.server
Deployed on Prefect Horizon (FastMCP runtime); see .fastmcp.yaml. The only
env var required to boot is TOLLBOOTH_NOSTR_OPERATOR_NSEC — every other
secret arrives via Secure Courier.
DPYC Ecosystem
Prior Art & Attribution
The methods, algorithms, and implementations contained in this repository may
represent original work by Lonnie VanZandt, first published on June 15, 2026.
This public disclosure establishes prior art under U.S. patent law
(35 U.S.C. 102).
All use, reproduction, or derivative work must comply with the Apache License
2.0 included in this repository and must provide proper attribution to the
original author per the NOTICE file.
How to Attribute
If you use or build upon this work, please include the following in your
documentation or source:
Based on original work by Lonnie VanZandt and Claude.ai
Originally published: June 15, 2026
Source: https://github.com/lonniev/cypher-mcp
Licensed under Apache License 2.0
Visit the technologist's virtual cafe for Bitcoin advocates and coffee
aficionados at stablecoin.myshopify.com.
Patent Notice
The author reserves all rights to seek patent protection for the novel methods
and systems described herein. Public disclosure of this work establishes a
priority date of June 15, 2026. Under the America Invents Act, the author
retains a one-year grace period from the date of first public disclosure to
file patent applications.
Note to potential filers: This public repository and its full Git history
serve as evidence of prior art. Any patent application covering substantially
similar methods filed after the publication date of this repository may be
subject to invalidation under 35 U.S.C. 102(a).
Further Reading
The Phantom Tollbooth on the Lightning Turnpike
— the full story of how we're monetizing the monetization of AI APIs, and
then fading to the background.
Software Factory mutation vocabulary (DPYC agents)
cypher-mcp is the graph substrate for the DPYC Software Factory: its agents (Porter =
Service Desk, Journeyman = Engineering) write an institutional-memory graph here without
ever holding a raw Cypher write tool. They call a fixed vocabulary of operator-authored,
parameterized write templates — record_triage, note_rejection, link_root_cause,
assert_rationale, bind_rationale_to_symbol, register_service — published as typed
cypher_<key> tools. assert_rationale hard-codes provenance:'llm-inferred-unverified'
as a Cypher literal, so an agent key can never claim authoritative provenance.
Start unlimited, limit later. Seeding just authors + publishes the tools; they then
appear in Pricing Studio unpriced. Price them and any funded patron can call — the two
agents just purchase api_sats like any patron. When you want to restrict calls to the two,
add — in a Pricing Studio session — a json_expression allow-list on patron.npub per tool
(Constraint Engine, not a bespoke ACL): listed npub allowed, everyone else denied by default,
runtime-mutable with no deploy. Containment is also by balance — fund the Porter thin and
the Journeyman thicker; a drained agent stops writing the graph but still triages on GitHub.
Seeding (operator, idempotent). scripts/seed_factory_vocabulary.py authors + publishes
the vocabulary. --dry-run needs no server or nsec and also prints the exact allow-list to
replicate in Pricing Studio when you limit access:
python scripts/seed_factory_vocabulary.py --dry-run \
--porter-npub npub1ymg... --journeyman-npub npub1m5q...
Apply against the live operator (operator nsec used transiently to sign one-shot kind-27235
proofs — never logged or written to disk). Add --gate (with both npubs) to also apply the
per-npub allow-list programmatically instead of in Pricing Studio:
python scripts/seed_factory_vocabulary.py \
--url https://cypher-mcp.fastmcp.app/mcp --operator-npub npub1fuhq0...
The vocabulary itself lives in scripts/factory_vocabulary.py (data, no I/O) and is covered
by tests/test_factory_vocabulary.py. Pipeline wiring (agents signing and calling these
tools), NIP-05 publication, and funding are downstream of this substrate.
Trademarks
DPYC™, Tollbooth DPYC™, and Don't Pester Your Customer™ are
trademarks of Lonnie VanZandt. See
TRADEMARKS.md
in the dpyc-community repository for usage guidelines.
License
Apache License 2.0 — see LICENSE and NOTICE for details.
Because in the end, the tollbooth was never the destination. It was always
just the beginning of the journey.