# Vector MCP Server

MCP (Model Context Protocol) server for **Vector** - the Apex Fusion eUTXO L2. Enables AI agents (Claude, GPT, Gemini, or any MCP client) to interact with Vector natively: query balances, send transactions, deploy and interact with smart contracts, manage on-chain agent identities, and submit protocol improvement proposals.

Built on [Ogmios](https://ogmios.dev/) + [Koios](https://www.koios.rest/) - no Blockfrost dependency.

**Vector mainnet is live.** Full guides: [Vector AI documentation](https://apex-fusion.github.io/vector-ai-documentation/).

## Hosted servers - no install

Hosted instances run on both networks, exposing all 24 tools:

| Network | Endpoint |
|---------|----------|
| Mainnet | `https://mcp.vector.mainnet.apexfusion.org/sse` |
| Testnet | `https://mcp.vector.testnet.apexfusion.org/sse` |

> **Deployment status: both networks are current.** Both hosted instances run today's
> completed migration: testnet since the 2026-07-31 morning merges (auto-deployed from
> `main`), mainnet since a deliberate cutover deploy the same day (see
> [docs/architecture/non-custodial-split.md](docs/architecture/non-custodial-split.md), section
> 11, "Rollout", for the full history). **Both hosted instances currently require a bearer
> token from the operators to connect** - that is an access control, not a custody one:
> neither instance accepts a mnemonic from any caller, token or not. Open public access
> (per-IP rate limiting, no token required) is a planned follow-up, not yet enabled on the
> hosted instances - the per-IP rate-limiting code ships in this release; only the ops action
> of unsetting `MCP_AUTH_TOKENS` remains, coordinated separately after this deploys. Self-host
> this release for tokenless access today.

> **Transport: the hosted URLs above still answer on `/sse` only.** This codebase now serves
> a modern Streamable HTTP endpoint, `/mcp`, alongside `/sse` + `/messages` - the legacy SSE
> transport, deprecated by the MCP spec (2026-07-28 revision), retained for compatibility.
> `/mcp` becomes each hosted instance's primary endpoint once this release merges and deploys
> - testnet automatically on the next push to `main`, mainnet on the next deliberate cutover
> dispatch, the same split the migration above went through. Until then,
> `https://mcp.vector.mainnet.apexfusion.org/mcp` and its testnet twin are not reachable;
> self-host this release (below) to use `/mcp` today.

Connect from Claude Code in one command. Both hosted instances require a bearer token from the
operators (contact the Apex Fusion team for one).

Modern transport (Streamable HTTP) - works today against a self-hosted instance (below); against
the hosted URLs above it goes live once each instance deploys this release (see the transport
note above):

```bash
claude mcp add --transport http vector-mcp <url>/mcp \
  --header "Authorization: Bearer <your-token>"
```

Legacy SSE transport - what the hosted URLs above actually answer on today:

```bash
claude mcp add --transport sse vector-mcp https://mcp.vector.mainnet.apexfusion.org/sse \
  --header "Authorization: Bearer <your-token>"
```

Self-hosting (below) needs no token, gives every caller open access to your own instance, and
serves `/mcp` today.

> **Security notice: the non-custodial migration is complete, in this codebase and on both
> hosted instances, as of the 2026-07-31 cutover deploy.** No tool in this repository accepts a
> mnemonic, private key, or any other key material. Every `build_*` tool constructs an unsigned
> transaction from a wallet *address* only, and every signing operation happens locally on your
> own machine, through the local signer companion. Broadcast the signed result with
> `vector_submit_transaction` - your seed phrase never leaves your machine, and no server
> running this release ever holds one. This is enforced mechanically in the code, not just by
> convention: the builder's custody boundary test scans every source file for key-material
> vocabulary against an allowlist that is now empty and pinned at size zero, so a future change
> cannot silently reintroduce a mnemonic parameter without failing that test by name.
> **This describes this release and the 2026-07-31 deploy specifically** - a later deploy is a
> separate operational action, not automatically covered by this notice; see the deployment
> status note above and
> [docs/architecture/non-custodial-split.md](docs/architecture/non-custodial-split.md) for the
> full rollout history.

Self-hosting instructions are below.

## Local signer (non-custodial path)

`packages/signer` is a local MCP server that holds your key and signs transactions locally
instead of handing your mnemonic to a shared host. It has **no network access at all** —
stdio transport, no Provider, no egress — so a key given to it never reaches a shared server
or your model provider. Four tools: `vector_signer_get_address`, `vector_signer_decode_transaction`,
`vector_signer_sign`, `vector_signer_get_spend_limits`.

**In this codebase, this signer is the single signing point for every family the builder
exposes.** The full non-custodial flow is live in this release for all of them:
`vector_signer_get_address` → `build_*` → `vector_signer_sign` → `vector_submit_transaction` →
`vector_await_transaction`. No step in that chain puts a mnemonic in front of a server running
this code, or your model provider, for any tool. The build → submit → await half is E2E-proven
on Vector testnet across the wallet/tx, smart-contract, agent-registry, and self-improvement
families, including the first keyless-built proposal submission the deployed self-improvement
module validator has ever accepted; see
[`packages/signer/README.md`](packages/signer/README.md#known-limitations) for exactly what that
testing does and does not exercise on the signer's side. **This describes the code, not every
deployment of it** - see the deployment status note above.

See [`packages/signer/README.md`](packages/signer/README.md) for configuration, tools, and known
limitations.

## Features

- **Wallet & queries** - balances, UTxOs, and transaction history for any address (no key material)
- **Keyless transaction building** - build unsigned AP3X/token/multi-output transactions and contract interactions; sign locally, broadcast via submit
- **Smart contracts** - deploy Plutus/Aiken validators, lock and spend UTxOs at script addresses (keyless)
- **Agent registry** - register, discover, update, transfer, and deregister on-chain AI agent identities via soulbound NFTs (keyless - build, sign locally, broadcast)
- **Agent messaging** - send on-chain messages between agents via TX metadata (keyless)
- **Self-Improvement Module** - browse, submit, critique, and endorse improvement proposals; the on-chain module is live on Vector mainnet, and every write tool is keyless in this codebase
- **Safety controls** - per-identity rate limiting; spend limits for every family are enforced by the local signer, per user - the server holds no spend-limit state of its own
- **Dual transport** - modern Streamable HTTP (`/mcp`) plus legacy SSE (`/sse` + `/messages`, deprecated by the MCP spec (2026-07-28 revision), retained for compatibility)

## MCP Tools (24)

### Wallet & Queries

| Tool | Description |
|------|-------------|
| `vector_get_balance` | Get AP3X and token balances for any address |
| `vector_get_utxos` | List UTxOs for an address |
| `vector_get_transaction_history` | Get transaction history for an address |

### Transactions

| Tool | Description |
|------|-------------|
| `vector_build_send_apex` | Build an unsigned AP3X payment (keyless — sign with the local signer) |
| `vector_build_send_tokens` | Build an unsigned native-token transfer (keyless) |
| `vector_build_transaction` | Build an unsigned multi-output transaction (keyless, never submits) |
| `vector_dry_run` | Simulate a transaction without submitting - estimate fees and validate |
| `vector_submit_transaction` | Broadcast an already-signed transaction (for example one signed by the local signer) |
| `vector_await_transaction` | Wait for a submitted transaction to be confirmed on-chain |

### Smart Contracts

| Tool | Description |
|------|-------------|
| `vector_build_deploy_contract` | Build an unsigned deployment of a Plutus V1/V2/V3 or Aiken validator (keyless) |
| `vector_build_interact_contract` | Build an unsigned lock or spend at a script address, with a redeemer (keyless) |

### Agent Registry

| Tool | Description |
|------|-------------|
| `vector_build_register_agent` | Build an unsigned agent registration - mints a soulbound identity NFT and locks a 10 AP3X deposit (keyless) |
| `vector_discover_agents` | Discover registered agents, filter by capability or framework (no wallet needed) |
| `vector_get_agent_profile` | Get an agent's full profile by DID (no wallet needed) |
| `vector_build_update_agent` | Build an unsigned update to an agent's name, description, capabilities, framework, or endpoint (keyless) |
| `vector_build_transfer_agent` | Build an unsigned transfer of agent ownership to a new address (keyless) |
| `vector_build_deregister_agent` | Build an unsigned deregistration - burns the identity NFT and returns the 10 AP3X deposit (keyless) |
| `vector_build_message_agent` | Build an unsigned on-chain message to an agent via TX metadata (label 674) (keyless) |

### Self-Improvement Module

| Tool | Description |
|------|-------------|
| `vector_self_improvement_browse` | Browse improvement proposals, critiques, and endorsements |
| `vector_self_improvement_analyze_metrics` | Proposal metrics: activity, adoption rate, treasury health, engagement |
| `vector_build_self_improvement_proposal_lock` | Build an unsigned proposal-stake lock (step 1 of 2, keyless) |
| `vector_build_self_improvement_proposal_spend` | Build an unsigned proposal submission - spends the lock and mints the proposal and activity tokens (step 2 of 2, keyless). Two transactions, agent-orchestrated. |
| `vector_build_self_improvement_critique` | Build an unsigned critique on a proposal - support, oppose, or propose amendments (keyless) |
| `vector_build_self_improvement_endorse` | Build an unsigned endorsement of a proposal by staking AP3X (keyless) |

Agent DIDs follow the format: `did:vector:agent:{policyId}:{nftAssetName}`

Example non-custodial flow for a registry op: `vector_build_register_agent` →
`vector_signer_sign` → `vector_submit_transaction` → `vector_await_transaction`.

## Self-hosting

### 1. Install and build

Requires Node.js >= 22 (matches `engines` in every `package.json` and the Dockerfile's
`node:22-alpine` base).

```bash
npm install
npm run build
```

**Dependency advisories.** `npm audit` currently reports 1 low-severity advisory: an `esbuild`
arbitrary-file-read issue that only triggers via its own Windows dev server, reachable solely
through `tsup` (a build-time-only dependency, absent from the production image, which installs
with `npm ci --omit=dev`). As of 2026-07-31 this tree carried 44 advisories, including 1
critical (`tar`, GHSA-23hp-3jrh-7fpw) that arrived because `@cardano-sdk/crypto` - pulled in
transitively through `@lucid-evolution/lucid` - declared the entire `npm` CLI package as a
runtime dependency. That dependency was dead weight: `@cardano-sdk/crypto`'s own published code
never requires `npm`, and neither `npm` nor `tar` appears anywhere in this server's built
bundle. Regenerating the lockfile picked up a newer `@cardano-sdk/crypto` release that dropped
the stray dependency outright, clearing all 43 of those advisories without any override needed;
`package.json` also carries a defensive `overrides` pin on `tar` and `brace-expansion` against
future regressions, though it is not what resolved this one.

### 2. Configure environment (optional)

```bash
cp .env.example .env
# Edit .env with your endpoint URLs (defaults point to Vector testnet; mainnet URLs below)
```

Every `build_*` tool is keyless: it takes a wallet address, never a mnemonic. No tool call
against this server ever needs a mnemonic parameter, for any family - see the security notice
above.

### 3. Run

```bash
npm start
# Server listens on port 3000 (configurable via PORT env var)
```

Connect with the modern transport:

```bash
claude mcp add --transport http vector-mcp http://localhost:3000/mcp
```

Add `--header "Authorization: Bearer <your-token>"` if you set `MCP_AUTH_TOKENS`. The legacy
SSE pair (`/sse` + `/messages`, deprecated by the MCP spec, retained for compatibility) is
still available at `http://localhost:3000/sse` for clients that need it.

If this instance will be reachable by anyone but you, set `MCP_AUTH_TOKENS` first - see [Configuration](#configuration) below.

### 4. Add to Claude Desktop

Add to your Claude Desktop MCP config (`claude_desktop_config.json`):

```json
{
  "mcpServers": {
    "vector": {
      "command": "node",
      "args": ["/path/to/vector-mcp-server/packages/builder/build/index.js"],
      "env": {
        "VECTOR_OGMIOS_URL": "https://ogmios.vector.testnet.apexfusion.org",
        "VECTOR_SUBMIT_URL": "https://submit.vector.testnet.apexfusion.org/api/submit/tx",
        "VECTOR_KOIOS_URL": "https://koios.vector.testnet.apexfusion.org/",
        "VECTOR_EXPLORER_URL": "https://vector.testnet.apexscan.org"
      }
    }
  }
}
```

For mainnet, use the mainnet endpoint table below. (No local setup needed if you use the hosted servers above.)

### Docker

```bash
npm run build
docker build -t vector-mcp .
docker run -p 3000:3000 vector-mcp
```

If this instance will be reachable by anyone but you, set `MCP_AUTH_TOKENS` first - see [Configuration](#configuration) below (`docker-compose.yml` in this repo binds `127.0.0.1` by default; the command above does not).

## Configuration

| Variable | Description | Default |
|----------|-------------|---------|
| `PORT` | HTTP server port | `3000` |
| `VECTOR_OGMIOS_URL` | Ogmios HTTP JSON-RPC endpoint | `https://ogmios.vector.testnet.apexfusion.org` |
| `VECTOR_KOIOS_URL` | Koios REST API endpoint | `https://v2.koios.vector.testnet.apexfusion.org/` |
| `VECTOR_SUBMIT_URL` | Transaction submit API | `https://submit.vector.testnet.apexfusion.org/api/submit/tx` |
| `VECTOR_EXPLORER_URL` | Block explorer base URL | `https://vector.testnet.apexscan.org` |
| `VECTOR_RATE_LIMIT_PER_MINUTE` | Max tool calls per minute, per identity (min `1`) | `60` |
| `VECTOR_MCP_SESSION_IDLE_MS` | `/mcp` session idle timeout before the reaper closes it, in ms (min `100`) | `600000` (10 min) |
| `VECTOR_MCP_SESSION_SWEEP_MS` | How often the `/mcp` idle reaper sweeps, in ms (min `100`) | `60000` (1 min) |
| `VECTOR_MCP_MAX_SESSIONS_PER_IDENTITY` | Max concurrent `/mcp` sessions per identity before the oldest is evicted (min `1`) | `32` |
| `MCP_AUTH_TOKENS` | Bearer tokens that may call this server. Comma-separated; each entry is `label:token` or a bare token. **When unset, the server is open to anyone who can reach it.** | _(unset — auth disabled)_ |

The four numeric knobs above fail loudly at startup on a malformed value: anything that is not
a plain integer, or is below its listed minimum, raises a startup error naming the variable and
the value it got, rather than silently falling back to some other behavior (an unparseable rate
limit silently disabling rate limiting, for example).

This server has no spend-limit or audit-log configuration of its own: it holds no key material
for any family, so it has nothing left to limit. Every spend limit, and the audit log recording
it, lives in your local signer instead - see `VECTOR_SIGNER_SPEND_LIMIT_PER_TX` /
`VECTOR_SIGNER_SPEND_LIMIT_DAILY` / `VECTOR_SIGNER_AUDIT_LOG_PATH` in
[`packages/signer/README.md`](packages/signer/README.md#configuration).

> **Running a public instance?** Set `MCP_AUTH_TOKENS` to gate access to known callers, each
> with its own rate-limit budget. With `MCP_AUTH_TOKENS` unset, callers are admitted
> anonymously with per-client-IP rate limits; the deployment's reverse proxy supplies the
> client address via the rightmost X-Forwarded-For entry. Tracked identities are capped (LRU);
> eviction resets a bucket's budget - a memory bound, not a security boundary, since an
> attacker rotating enough source IPs can still defeat per-IP limiting at a tier only the
> reverse proxy or network layer can police. `/mcp` sessions get the same per-identity
> treatment: idle sessions are reaped (`VECTOR_MCP_SESSION_IDLE_MS`, swept every
> `VECTOR_MCP_SESSION_SWEEP_MS`), and concurrent sessions per identity are capped
> (`VECTOR_MCP_MAX_SESSIONS_PER_IDENTITY`) - see the Configuration table above for defaults and
> minimums.

> **Malformed values fail loudly, not silently.** The server refuses to start if
> `MCP_AUTH_TOKENS` contains an empty token, a token with embedded whitespace, a
> duplicate token, or a value where every comma-separated entry is blank (e.g. a
> stray `,,,`) — each raises a startup error that names the problem but never
> echoes a token value. Commas delimit entries and cannot be escaped, so generate
> tokens from a comma-free charset (hex / base64url / alphanumeric).

### Mainnet endpoints

| Variable | Mainnet value |
|----------|---------------|
| `VECTOR_OGMIOS_URL` | `https://ogmios.vector.mainnet.apexfusion.org` |
| `VECTOR_SUBMIT_URL` | `https://submit.vector.mainnet.apexfusion.org/api/submit/tx` |
| `VECTOR_KOIOS_URL` | `https://v2.koios.vector.mainnet.apexfusion.org/` |
| `VECTOR_EXPLORER_URL` | `https://vector.apexscan.org/en/` |

## Testing

```bash
npm run test:unit
```

No wallet, no network — pure logic only (CBOR encode/decode assertions).

```bash
npm run test:smoke
```

Builds the server, boots it, and asserts the exposed tool inventory matches the checked-in snapshot. No wallet, no external network. CI runs this and `test:unit` on every PR.

```bash
echo "your mnemonic words here" > packages/builder/mnemonic.txt
npm run test:integration
```

Requires `mnemonic.txt` in `packages/builder/` containing a **funded Vector testnet** mnemonic. Covers the core tools end-to-end against Vector testnet, including the full agent lifecycle: register, discover, profile, update, transfer, message, and deregister (all keyless now: build → sign → submit → await per step). Also runs `keyless-build.test.ts`, `registry-keyless.test.ts`, and `self-improvement-keyless.test.ts` - tier-1 suites needing no mnemonic at all, each building unsigned transactions against live public data only (`vector_build_send_tokens` is covered offline, by unit tests and the legacy suite above; `self-improvement-keyless.test.ts` covers critique, endorse, and proposal-lock builds, plus a not-found rejection path on proposal-spend). Set `VECTOR_E2E_SUBMIT=1` to additionally run each family's gated end-to-end suite, fully on-chain: `keyless-e2e.test.ts` lands one real self-send (~0.16 AP3X fee); `registry-e2e.test.ts` runs a full register → update → deregister agent lifecycle (the 10 AP3X deposit round-tripped exactly, fees only as net cost); `self-improvement-e2e.test.ts` locks and spends a real improvement proposal through the deployed module validator, then critiques and endorses it (≈48 AP3X in stakes and module minimums, plus six transaction fees, one-way - the stakes are locked by the module's own design, not lost). Set `LEGACY_FULL=1` to additionally exercise the same self-improvement lock → spend sequence inside `run.test.ts` itself (off by default, since `self-improvement-e2e.test.ts` already proves that exact path). Never runs in CI.

```bash
npm run test:smoke:signer
```

Builds the local signer (`packages/signer`), boots it over stdio, and exercises all four of
its tools, including the fail-closed audit-write-failure path. No wallet, no network. CI runs
this on every PR alongside the two smoke tests above.

```bash
export VECTOR_SIGNER_MNEMONIC_FILE=/absolute/path/to/testnet-mnemonic.txt
npm run test:integration:signer
```

Requires a **funded Vector testnet** wallet. Builds a real unsigned transaction the way the
hosted builder does (no key), then has the local signer decode, policy-check, and sign it
against live chain data. **Never submits.** Never runs in CI. See
[`packages/signer/README.md`](packages/signer/README.md#testing).

## Architecture

```
┌──────────────────────┐             ┌──────────────────────────┐
│  Claude / GPT / etc. │◄───────────►│  vector-mcp-server       │
│  (any MCP client)    │ /sse + /mcp │                          │
└──────────────────────┘             │  ┌────────────────────┐  │
                                     │  │ Rate Limiter        │  │
                                     │  │ (60 calls/min)      │  │
                                     │  └────────┬───────────┘  │
                                     │           │               │
                                     │  ┌────────▼───────────┐  │
                                     │  │ Lucid + Ogmios     │  │
                                     │  │ Provider            │  │
                                     │  └────────┬───────────┘  │
                                     │           │               │
                                     │  ┌────────▼───────────┐  │
                                     │  │ Ogmios / Koios /   │  │
                                     │  │ Submit API          │  │
                                     │  └────────────────────┘  │
                                     └──────────────────────────┘
```

No safety layer sits between the rate limiter and the provider: this server holds no key
material for any family, so it has no spend limits of its own left to enforce. Every spend
limit lives in your local signer instead.

## About Vector

Vector is Apex Fusion's eUTXO L2, running Cardano mainnet parameters (Conway era, Plutus V3). Sub-1-second optimistic finality and deterministic fees make it a natural chain for AI agent workloads. Mainnet is live.

- **Docs:** https://apex-fusion.github.io/vector-ai-documentation/
- **Explorer (mainnet):** https://vector.apexscan.org/en/
- **Explorer (testnet):** https://vector.testnet.apexscan.org
- **Apex Fusion:** https://apexfusion.org