Install

Three install paths: Claude Desktop (one command), Cursor, or any generic stdio MCP client. Plus the always-on hosted HTTP endpoint at mcp.agenttrust.tech for cloud agents.

Claude Desktop (recommended)

Add to your config — ~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows:

{
  "mcpServers": {
    "agenttrust": {
      "command": "npx",
      "args": ["-y", "@agenttrust-sdk/mcp"],
      "env": {
        "RPC_URL": "https://api.devnet.solana.com",
        "NETWORK": "solana-devnet"
      }
    }
  }
}

Restart Claude Desktop. Twenty-one tools are now available in chat. No clone, no local build.

Local clone (for development)

If you want to iterate on the MCP server's source, swap the command/args:

"command": "node",
"args": ["/absolute/path/to/agenttrust/mcp/dist/index.js"]

Or run the helper that wires the local path automatically:

mcp/scripts/install-claude-desktop.sh

The script edits the Claude Desktop config in place. It backs up the prior config to claude_desktop_config.json.bak.<timestamp> so you can revert.

Cursor

Cursor's MCP config lives at ~/.cursor/mcp.json (or per-workspace .cursor/mcp.json). Same shape as Claude Desktop:

{
  "mcpServers": {
    "agenttrust": {
      "command": "npx",
      "args": ["-y", "@agenttrust-sdk/mcp"]
    }
  }
}

Generic stdio MCP client

The package ships a binary entry point. Once installed:

pnpm add @agenttrust-sdk/mcp
node ./node_modules/@agenttrust-sdk/mcp/dist/index.js   # stdio transport, default

The server speaks MCP over stdin/stdout. Any compliant MCP client attaches by spawning this command.

Hosted HTTP endpoint

The public hosted MCP HTTP endpoint is already live:

https://mcp.agenttrust.tech

Health check:

curl https://mcp.agenttrust.tech/healthz
# → {"ok":true,"service":"agenttrust-mcp","version":"0.4.5","network":"solana-devnet","toolCount":21,…}

Hosted on Fly.io (Singapore region, shared-cpu-1x@256MB, always-on with auto-resume on idle). Use this URL in any MCP client that speaks StreamableHTTPServerTransport — no local install required. Full hosted-endpoint reference: Hosted endpoint.

To run your own HTTP transport locally:

MCP_TRANSPORT=http MCP_HTTP_PORT=8765 node ./mcp/dist/index.js

Behind any reverse proxy (Caddy, nginx, Vercel, Fly.io) this surfaces as a public hosted endpoint.

Write tools — adding a keypair

The eight write tools (agenttrust_init_authority, agenttrust_init_policy, agenttrust_set_killswitch, agenttrust_register_namespace, agenttrust_register_attestor, agenttrust_request_validation, agenttrust_respond_to_validation, agenttrust_emit_feedback) require a signing keypair. The MCP server resolves a signer through a four-step chain (first match wins):

1. KEYPAIR_B58 — base58-encoded 64-byte secret key
2. KEYPAIR_PATH — absolute path to a JSON-array secret-key file (Solana CLI native format)
3. ~/.config/solana/id.json — Solana CLI's default keypair location, picked up automatically
4. SOLANA_KEYPAIR_PATH — alt path env some tooling sets

If you already use solana-keygen locally, no env is needed. To set an explicit signer in the Claude Desktop config, add KEYPAIR_B58 to the env block:

{
  "mcpServers": {
    "agenttrust": {
      "command": "npx",
      "args": ["-y", "@agenttrust-sdk/mcp"],
      "env": {
        "RPC_URL":     "https://api.devnet.solana.com",
        "NETWORK":     "solana-devnet",
        "KEYPAIR_B58": "<base58-encoded 64-byte secret key>"
      }
    }
  }
}

Without any usable signer, write tools surface a clear auth_required envelope. Read and discovery tools never need one.

The auth_required envelope

Write tools that fail the signer check return a structured envelope, not a raw chain error. The hint copy is branched by transport:

// Local install (stdio): tell the developer how to wire a keypair
{
  "errorCode": "auth_required",
  "message":   "Signer required (needed by `agenttrust_init_policy`).",
  "hint":      "Set KEYPAIR_B58 (base58-encoded 64-byte secret), KEYPAIR_PATH, or `solana config get` to point at a funded keypair, then restart the MCP server.",
  "cause":     "This tool requires a signer. Set one of: KEYPAIR_B58, KEYPAIR_PATH, or `solana config get`."
}

// Hosted (HTTP): point the caller at the local-install path
{
  "errorCode": "auth_required",
  "message":   "Signer required (needed by `agenttrust_init_policy`).",
  "hint":      "This is the hosted read-only endpoint. To use write tools, install MCP locally: npx -y @agenttrust-sdk/mcp@latest. Hosted MCP signs nothing on your behalf by design — your keypair stays on your machine.",
  "cause":     "This tool requires a signer. Set one of: KEYPAIR_B58, KEYPAIR_PATH, or `solana config get`."
}

The hosted endpoint at mcp.agenttrust.tech is read-only by design and ships no signer. A shared signer would mean every user's on-chain identity is owned by the operator; that's a security model, not a UX shortcut. For write tools, install the MCP locally with your own keypair. See /quickstart for the surface comparison table.

Convert a Solana CLI keypair to base58:

solana-keygen recover --output-format json -k ~/.config/solana/id.json | jq -r '.privateKey' \
  | python3 -c "import sys, base58, json; print(base58.b58encode(bytes(json.loads(sys.stdin.read()))).decode())"

Or use the bs58 CLI:

cat ~/.config/solana/id.json | jq -r '.[0:64]' | npx bs58 encode

Environment variables

Build + test from source

git clone https://github.com/agenttrust-labs/agenttrust && cd agenttrust
pnpm install
pnpm --filter ./trustgate/sdk run build   # MCP depends on the SDK build output
pnpm --filter ./mcp run build
pnpm --filter ./mcp test                  # 76 unit tests, no chain access
INTEGRATION=1 pnpm --filter ./mcp test:integration   # devnet round-trip

IDL fetch (verify on-chain truth)

All three Anchor IDLs are published on devnet:

anchor idl fetch 8Y6fGeNEHgmWmbt8JsRcF72jxbeBfJhomMjG6SuoJQTR --provider.cluster devnet  # policy_vault
anchor idl fetch HF8zHfoyA7b5mhLViopTnRMprc6ZT5KActHTdkFrih2N --provider.cluster devnet  # trustgate
anchor idl fetch Cx4RFa6ysw3qXYhugPkF8pFSWBkmKq59h2dWgF2tKhtv --provider.cluster devnet  # validation_registry

The MCP server bundles snapshots at mcp/src/idl/*.json as a defensive fallback (saves an RPC round-trip on cold start; keeps the server bootable in offline / air-gapped harnesses). Latest evidence snapshot: docs/proofs/idl-on-chain.json.

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