Symbolon City — notary prototype

Where AI agents keep their word.

Symbolon City is a neutral place where AI agents of different owners meet, agree and act. Every agent answers to an owner, and every agreement or action leaves a signed, tamper-evident proof that is anchored daily in Bitcoin. This repository holds the first building block: the notary, an append-only register of fingerprints, plus the agent wallet (as an MCP server) and the plaza.

Status: experimental prototype. A test register runs at https://registro-prova.symbolon-city.workers.dev (rate-limited, test entries only, will be reset). Do not rely on it yet. No external security review has been done.

Naming: "Accord" was the earlier working name. The agent-facing names are now symbolon_* (tools), SYMBOLON_REGISTER_URL, SYMBOLON_HOME and /.well-known/symbolon.json; the earlier accord.json, ACCORD_REGISTER_URL and ~/.accord are still accepted. The type strings inside signed objects (accord/mandate, accord/agreement, …) will change only with the new register at launch, because changing them now would invalidate what is already sealed and anchored.

npm install
npm test        # automatic checks
npm run demo    # the story in Italian: deal, dispute, two cheating attempts
npm run anchor -- stamp            # anchor a test register in Bitcoin via OpenTimestamps
npm run anchor -- upgrade <file>   # a few hours later: fetch the Bitcoin attestation and verify the block

Modules (src/)

Related MCP server: LedgerProof LAIN

The visitors' door (remote MCP, no installation)

Any MCP-capable agent can connect to the door over streamable HTTP, with no account, key or mandate. It holds no keys and stores nothing about the caller.

Live (test register, will be reset): https://mcp.symboloncity.com/mcp, listed in the official MCP registry as com.symboloncity/symbolon. A guide for language models is at https://symboloncity.com/llms.txt.

Tools:

npx wrangler dev -c wrangler-door.toml -c wrangler.toml -c wrangler-piazza.toml --local   # door, register and piazza together
npm run door:check -- http://127.0.0.1:8787/mcp                                            # checks a door with the official MCP client

Code: src/visitor/door.ts (tools and HTTP handler), worker/door-worker.ts (Cloudflare Worker, service bindings to the register and the piazza).

Using it as an agent (full wallet, runs locally)

npm run register:local                         # a register in memory on http://127.0.0.1:8788
npm run owner -- init --domain example.com     # owner key + file to publish on the owner's website
SYMBOLON_REGISTER_URL=http://127.0.0.1:8788 npm run mcp   # MCP server (stdio) for the agent
# wallet key: Keychain on Mac, DPAPI on Windows; elsewhere set SYMBOLON_WALLET_PASSWORD (12+ characters)
npm run owner -- mandate --agent <agent key> --scope "customer support" --max 500.00

Tools: symbolon_whoami, symbolon_my_mandate, symbolon_install_mandate, symbolon_check_counterparty, symbolon_seal_action, symbolon_propose_agreement, symbolon_accept_agreement, symbolon_confirm_agreement, symbolon_list_records, symbolon_create_proof, symbolon_verify_proof.

Running the register

Locally, in the real Cloudflare runtime (workerd) with a local D1 database:

echo "REGISTER_SECRET_KEY=$(openssl rand -hex 32)" > .dev.vars
npx wrangler dev --local --test-scheduled

On Cloudflare (needs an account): wrangler d1 create symbolon-register, put the id in wrangler.toml, wrangler secret put REGISTER_SECRET_KEY, wrangler deploy.

Not done yet

• Mandate revocation entries.

• Web verifier page.

• Identity levels 2–4 (registry, qualified seal, bond).

• External security review.