# sigil [Health: Active] **Category:** 💻 Developer Tools **Repository:** https://github.com/cdrn/sigil **GitHub Stars:** 3 **Views:** 0 **Installs:** 0 **Upvotes:** 0 **Directory Page:** https://allmcps.com/mcp/sigil-2 ## Description Local keystore + MCP server. Claude can sign EVM transactions but never sees the private key. ## Claude Desktop Quick Installation Heuristic fallback — verify the package name and runner against the repository README before running it. Uses `npx` (confidence: low): ```json "mcpServers": { "sigil": { "command": "npx", "args": ["-y","sigil-2"] } } ``` ## Documentation & README # sigil > Claude can sign, but never see. `sigil` is a local signing tool and Claude Code integration that lets agentic coding tools use private keys without ever putting key material in the model's context window. **Status:** pre-alpha. The MCP server, CLI, unlock flow, ward hooks, policy engine (static checks), out-of-band confirmation via ntfy, Solana signing, and the JSON-RPC signing proxy (Foundry/Hardhat) all work end-to-end. Rolling-window value caps and EIP-712 domain allowlists are not yet implemented. Until they land — and until the supply-chain attestations promised for v0.1.0 ship — **do not use this with real funds yet.** Build plan lives in the [tracking issue](https://github.com/cdrn/sigil/issues/9). ## What it is One MCP server process, four bins (plus a legacy `sigild` alias), six runtime deps (all pinned, zero transitive): 1. **`sigil-mcp`** — the only thing that runs. Claude Code spawns it per session via your `mcpServers` config; it dies when Claude exits. Holds unlocked keys in process memory (zeroized on shutdown, `sigil lock`, or unlock-failure; mlock against swap is planned). Keys at rest are encrypted with XChaCha20-Poly1305 and an Argon2id-derived key. Signs over stdio using a DIY MCP wire protocol (~200 lines, no SDK dep). Claude never sees key material — only opaque handles like `evm:executor`. 2. **`sigil`** — control CLI. `init`, `status`, `portal new`/`add`/`list`/`qr`/`remove`, `policy show`/`init`, `unlock`, `lock`. 3. **`sigil-hook-pre` / `sigil-hook-post`** — Claude Code hook binaries that block reads of common key paths and redact key-shaped strings from tool output. `sigil-mcp` boots **locked**: empty in-memory handle table, no keys loaded. Sign methods return `DAEMON_LOCKED` (-32003) with a "run sigil unlock" message until you push the passphrase in from a separate terminal via `sigil unlock`. That CLI connects to a per-session Unix socket at `~/.sigil/control/.sock` (0600) that `sigil-mcp` opens at startup — and fans out to every such socket so one `sigil unlock` reaches all open windows. After unlock, signs work for the rest of the session; `sigil lock` zeroizes the table without killing the process. Sign methods exposed today: EIP-191 personal_sign, EIP-1559 + legacy transactions, EIP-712 typed data, plus Solana (ed25519) message + transaction signing — see [Solana support](#solana-svm) below. ## What it isn't - Not a hardware wallet replacement. If you can use a Ledger or YubiKey, do that. - Not a custody solution. It runs on your laptop or VPS and protects you from one specific class of failure: leaking key material through an LLM agent. - A first cut of *bounding signing authority* via the policy engine — but not the full thing. Shipped: static checks (chain ID, destination allowlist, per-tx value cap, function-selector allowlist, contract-creation gating, on/off toggles for personal_sign and EIP-712) plus out-of-band human confirmation via ntfy. Rolling-window caps and EIP-712 domain allowlists are tracked in [#3](https://github.com/cdrn/sigil/issues/3) and will land incrementally. ## Install ```sh npm install -g sigild ``` This drops four binaries on your `$PATH`: `sigil`, `sigil-mcp`, `sigil-hook-pre`, `sigil-hook-post` (plus `sigild`, a legacy alias for `sigil-mcp`). (The package name on npm is `sigild` for legacy reasons; the bins do not include a daemon any more.) Requires Node 22+, macOS or Linux. (The CLI ↔ session control channel uses Unix domain sockets; Windows is untested and currently unsupported.) ## Quick start ```sh # 1. Wire sigil into Claude Code (project-scoped). Pass --user to do it globally. sigil init # 2a. Generate a fresh key inside sigil (no plaintext ever hits disk): sigil portal new evm:bot # → prompts for a passphrase, mints a fresh secp256k1 key, prints the # address, writes ~/.sigil/keys/evm:bot.sigil + permissive policy. # # 2b. OR import an existing private key from a file: # Accepts either 32 raw bytes or 64 hex chars (with optional 0x prefix). sigil portal add evm:bot --key-file ./private.hex # → same as above but seeded from the file. Source file is deleted by # default (pass --no-remove-source to keep it). # # Either form: pass --strict to start with a locked-down policy template # you fill in before any sign succeeds. # 3. Open Claude Code. It spawns sigil-mcp automatically via your MCP config. # sigil-mcp boots locked — the first sign attempt will return DAEMON_LOCKED. # 4. In a separate terminal, push the passphrase to every running sigil-mcp. sigil unlock # → prompts once, decrypts every keyfile in ~/.sigil/keys/ into each open window # 5. Use Claude Code. The sigil_* tools (EVM + Solana) will work for the rest of the session. # Optional: re-lock without restarting Claude. sigil lock ``` If you close Claude Code, `sigil-mcp` exits and its memory is wiped. Open a new session and `sigil unlock` again — the encrypted keyfiles on disk persist. ## CLI reference ```text sigil init [--user] Project scope: writes the ward hooks to /.claude/settings.json and the MCP server registration to /.mcp.json. --user: writes hooks to ~/.claude/settings.json and the MCP server registration to ~/.claude.json. (Claude Code CLI reads MCP configs from .mcp.json / ~/.claude.json — not from settings.json.) Idempotent — preserves your unrelated settings, and on upgrade migrates any stale mcpServers.sigil entry out of settings.json. sigil portal new [--strict] Generate a fresh secp256k1 key inside sigil, encrypt with your passphrase, write it to ~/.sigil/keys/.sigil (mode 0600). No plaintext key ever lands on disk. Use this when you want a clean hot wallet for a bot (vs importing an existing key from a file). Also writes ~/.sigil/policy/.toml — permissive by default, or --strict for a locked-down template. sigil portal add --key-file [--no-remove-source] [--strict] Import an existing private key. Encrypts it with your passphrase and stores at ~/.sigil/keys/.sigil (mode 0600). Handle format is : where kind is "evm". The source key file is deleted by default — pass --no-remove-source to keep it. Also writes ~/.sigil/policy/.toml — permissive by default (signs anything), or --strict for a locked-down template you fill in before signs succeed. sigil policy show Print the current policy file for a portal. Validates schema; exits 1 if the file is missing or malformed. sigil policy init [--strict] Provision a policy file for an existing portal whose policy is missing (e.g. a keyfile from an older sigil version, or one you manually deleted). Refuses to overwrite — edit the file directly or remove it first. Defaults to permissive; --strict writes the locked-down template. sigil rpc init --upstream [--port ] Enable the JSON-RPC signing proxy for a portal: generates a strong auth token and appends the [rpc] block to ~/.sigil/config.toml (refuses if one exists; preserves the rest of the file). Prints the ready-to-paste authenticated endpoint and forge invocation. Restart Claude Code sessions to pick it up. sigil portal list List the encrypted keyfiles on disk with their derived addresses (EVM + Solana). Requires the passphrase. sigil portal qr Render a portal's address as a terminal QR code (for funding it from a phone wallet). Requires the passphrase. sigil portal remove Delete a keyfile from disk. sigil unlock Prompt for the passphrase and push it to every running sigil-mcp at once (one per Claude window). After unlock, sign calls succeed for the rest of each session. Idempotent — sessions already unlocked are left as-is. Fails if no sigil-mcp is running (start a Claude Code session first). sigil lock Tell every running sigil-mcp to zeroize and clear its in-memory keys. Re-unlock with sigil unlock — the sigil-mcp processes keep running. sigil status Report which sigil-mcp sessions are running (one entry per window, with PID, unlocked flag, and loaded portals) and how many keyfiles exist on disk. Does not require the passphrase. ``` Set `SIGIL_HOME` to override `~/.sigil`. Set `SIGIL_CONTROL_DIR` to override the control-socket directory. ## Multi-window behaviour Each Claude Code window spawns its own `sigil-mcp`, and each binds its own control socket at `~/.sigil/control/.sock`. They share the on-disk keyfiles + audit log but keep separate in-memory handle tables. `sigil unlock` / `lock` / `status` fan out across **every** socket in `~/.sigil/control/`, so a single `sigil unlock` loads keys into all currently-open windows — no more guessing which process the CLI reaches. Sockets left behind by hard-killed sessions are detected and cleaned up automatically on the next CLI call. Each window still holds its own decrypted keys only for its own lifetime: closing a window zeroizes that session's keys, and a window opened *after* you unlock starts locked (run `sigil unlock` again to include it). Keys never outlive the Claude sessions that use them — a deliberate property from [#23](https://github.com/cdrn/sigil/issues/23). OS-keychain integration (planned, v0.3) will make unlock zero-touch for users who set it up. ## Policy engine Once a portal is unlocked, signing authority over its key is real. To bound the blast radius of a successful prompt injection, every portal has a policy file at `~/.sigil/policy/.toml`. Two modes: **Permissive** (default for `sigil portal add`): no rules. Sign anything the agent asks. The key isolation guarantees still hold — your key never enters the agent's context — but the unlocked portal can be made to sign whatever an attacker can get the agent to ask for. Useful for: testnet bots, demo flows, anyone who only cares about the context-window protection. **Strict** (opt in with `--strict`): every sign request is checked. Generated template: ```toml mode = "strict" chain_ids = [1] # allowed chain IDs allow_to = [] # allowed destination addresses (lowercase 0x) max_value_wei = "0" # per-tx cap, in wei, as decimal string allowed_selectors = [] # 4-byte function selectors, e.g. "0xa9059cbb" allow_contract_creation = false # deploys (to = null); when true, every # deploy still requires a confirm tap allow_message_signing = false # EIP-191 personal_sign (e.g. SIWE) allow_typed_data = false # EIP-712 (Permit, OpenSea — can be financial) # Optional: above this value, sigil pushes a notification to your phone and # waits for an approve/deny tap before signing. See "Out-of-band confirm" # below. Must be strictly less than max_value_wei. require_confirm_above_wei = "10000000000000000" # 0.01 ETH ``` A failed rule throws `POLICY_DENIED` (-32001) back to the agent with the human-readable reason ("tx denied — value X exceeds max_value_wei Y"), and the deny is appended to the hash-chained audit log alongside allows. Denies are forensically the more interesting half — they're the prompt-injection canary. What's deferred to follow-up PRs (still in [#3](https://github.com/cdrn/sigil/issues/3)): rolling-window value caps (e.g. 1 ETH/day per portal), EIP-712 domain + primary-type allowlists, decoded-calldata arg checks. ## Out-of-band confirm For sign requests above `require_confirm_above_wei`, sigil pushes a notification to a channel you control (not the agent) and waits for an explicit human ack before signing. Today the only transport is [ntfy](https://ntfy.sh) — zero-setup, no accounts. SMS and Telegram transports are wired behind the same `ConfirmTransport` interface and will land in follow-ups. Wire it up in `~/.sigil/config.toml`: ```toml [confirm.ntfy] topic = "your-unguessable-string-here" # the topic name IS the credential # server = "https://ntfy.example.com" # optional, default https://ntfy.sh [confirm] # timeout_ms = 60000 # default 60s; timeout = deny ``` Install the ntfy app on your phone, subscribe to that topic, and you'll get a push with **Approve** / **Deny** buttons every time the threshold is crossed. The buttons hit a local `127.0.0.1` listener inside `sigil-mcp` with a one-time, request-bound token — a leaked or replayed token can't approve a different sign. Timeout, deny click, and push-provider outage all fail closed. If any policy file sets `require_confirm_above_wei` but no transport is configured, `sigil-mcp` refuses to start with a clear error rather than silently degrading every confirm-gated sign to a deny. ## JSON-RPC signing proxy (Foundry / Hardhat / any web3 tool) sigil can expose a local JSON-RPC endpoint that makes any portal a drop-in signer for tooling that expects an unlocked node account — the same pattern Clef and web3signer use. Contract bytecode goes from `forge` straight into sigil; it never transits the agent's context or an MCP tool parameter. Enable it with one command (generates the token, writes the config block, prints the forge invocation): ```sh sigil rpc init evm:bot --upstream https://sepolia.example/v3/KEY ``` ...or by hand in `~/.sigil/config.toml`: ```toml [rpc] portal = "evm:bot" # which portal signs upstream = "https://sepolia.example/v3/KEY" # real node for everything else token = "" # required — guards the endpoint # port = 8547 # default 8547 (clear of anvil's 8545) ``` Then point any tool at it, with the token as the Basic-auth password: ```bash forge script script/Deploy.s.sol \ --rpc-url "http://sigil:@127.0.0.1:8547" \ --unlocked --sender 0xYourPortalAddress --broadcast ``` The proxy serves three things with the portal key and forwards everything else (`eth_call`, `eth_estimateGas`, `eth_getTransactionReceipt`, …) to the upstream: - `eth_accounts` → the portal address (empty while locked) - `eth_signTransaction` → fills nonce/gas/fees if missing, signs, returns the raw tx - `eth_sendTransaction` → same, then broadcasts via the upstream and returns the hash **Security properties.** The listener binds `127.0.0.1` only; every request must present the config token (constant-time compared) and a loopback `Host` header (DNS-rebinding defence). Signing runs through the *identical* daemon pipeline as the MCP tools — policy checks, the out-of-band confirm gate, and the hash-chained audit log all apply, so this surface adds a transport, not a privilege. The filled transaction carries the **upstream's** chain id, so a strict policy's `chain_ids` allowlist binds the proxy to the network you configured. Message/typed-data methods (`eth_sign`, `personal_sign`, `eth_signTypedData*`) are rejected on this surface — use the MCP tools, which have their own policy toggles. A strict policy with `allow_contract_creation = true` gives you confirm-gated `forge script` deploys: forge submits, your phone buzzes, the tx signs when you tap approve. With multiple Claude windows open, each `sigil-mcp` tries to bind the port; the first wins and the rest log and continue — any one session's proxy serves the machine. When the proxy is enabled, sigil-mcp advertises the endpoint — including the authenticated URL — in the `sigil_eth_sign_transaction` tool description, so the agent discovers it on its own and reaches for `forge --unlocked` instead of transcribing bytecode through the MCP tool. This is deliberate: the token gates other local software, not your agent (see THREAT_MODEL.md). ## Solana (SVM) Every portal also controls a **Solana address**, derived from the *same secret*. EVM uses secp256k1; Solana uses ed25519 — different curves, so you can't share a public key. But the portal's raw 32-byte secret doubles as an ed25519 seed, yielding one secret → two addresses: ``` $ sigil portal list evm:executor evm: 0x1234…abcd svm: 7vWxK…Qm9f # base58 ed25519 address, same key ``` This is exactly the derivation Phantom/Solflare perform on **"import private key"**, so the Solana address is recoverable there (it does *not* match a seed-phrase / BIP44 account — it's the raw-key account). Two MCP tools: - **`sigil_svm_sign_message`** — sign arbitrary off-chain bytes (e.g. Sign-In With Solana) with the ed25519 key. Input is base64; returns a base58 signature. - **`sigil_svm_sign_transaction`** — pass a serialized Solana transaction *message* (base64, legacy or v0); sigil ed25519-signs those bytes and returns the base58 signature for you to assemble into the transaction. **Policy.** Solana hides most semantics behind account indices and on-chain state, so sigil only decodes what it can offline: **native SOL (System Program) transfers**, which it gates on `svm_allow_to` (base58 recipient allowlist) and `svm_max_lamports` (per-tx cap), exactly like EVM. Anything it *can't* fully decode — SPL tokens, program calls, address-lookup-table accounts — is **routed to the out-of-band confirm gate**, never silently allowed. Auto-allow is all-or-nothing: a tx is only signed without a human tap if **every** instruction decoded and passed policy. `require_confirm_above_lamports` adds a value threshold (and, in strict mode, the undecodable-tx confirm); in strict mode an undecodable tx with no confirm transport configured fails closed (deny). Relevant policy fields (`~/.sigil/policy/.toml`): `allow_svm_message_signing`, `svm_allow_to`, `svm_max_lamports`, `require_confirm_above_lamports`. ## Supply chain posture Key-management libraries die from supply chain compromise, not from clever attacks on the code. Given the npm ecosystem in 2026 (Mini Shai-Hulud, Axios, pgserve, TanStack), `sigil` commits to: - **Zero install scripts.** No `postinstall`, `preinstall`, `prepare`. CI-enforced: every PR runs a guard that fails if any package in the resolved tree declares one. - **Six runtime deps, all version-pinned** (no caret ranges), all zero-transitive — the entire `npm ls --omit dev` tree is exactly these six packages: - [`@noble/ciphers`](https://github.com/paulmillr/noble-ciphers) for XChaCha20-Poly1305 - [`@noble/hashes`](https://github.com/paulmillr/noble-hashes) for Argon2id, keccak256, sha2/sha512, HMAC - [`@noble/secp256k1`](https://github.com/paulmillr/noble-secp256k1) for ECDSA (EVM) - [`@noble/ed25519`](https://github.com/paulmillr/noble-ed25519) for EdDSA (Solana) - [`@iarna/toml`](https://github.com/iarna/iarna-toml) for parsing per-portal policy TOML files - [`qrcode-generator`](https://github.com/kazuhikoarase/qrcode-generator) for `sigil portal qr` rendering - **No MCP SDK.** The official `@modelcontextprotocol/sdk` pulls 92 transitive deps (ajv, hono, cors, cross-spawn, etc) — unacceptable surface. We implement the MCP wire protocol directly in ~200 lines. - **No Bun.** Plain Node only. Bun is currently being weaponized by Mini Shai-Hulud as an evasion layer; we will not give that pattern any cover. - **Provenance attestations on every npm publish.** Starting v0.0.4, releases are built by [a GitHub Actions workflow](https://github.com/cdrn/sigil/blob/HEAD/.github/workflows/release.yml) under OIDC trusted-publisher auth, signed with a Sigstore attestation. No long-lived npm token; tampered or out-of-band publishes fail signature verification. - **CycloneDX SBOM attached to every GitHub Release.** Full transitive dep tree enumerated at release time. - **Install-scripts CI guard.** Every PR fails if any package in the resolved tree declares `preinstall` / `install` / `postinstall`. `.npmrc` already has `ignore-scripts=true` so these never actually run for us; the guard catches new transitive deps that might run for a user without our `.npmrc`. - **Still planned for v0.1.0:** - Signed standalone binaries from GitHub Releases for users who'd rather not touch npm - Action SHA pinning rotation via Dependabot ## Verifying a release You can confirm a `sigild` tarball was built by the public workflow at the commit it claims to come from: ```sh # Validates every package in your install tree: npm audit signatures # Inspect the attestation for a specific sigild version: npm view sigild@ dist.attestations # → shows the workflow filename, the commit SHA, and the Sigstore signing cert ``` What the attestation tells you: this tarball was built by `cdrn/sigil`'s `.github/workflows/release.yml`, at a specific commit on `main`, at a specific time. It does *not* tell you that commit is non-malicious — for that, read the diff between the version you trust and the version you're upgrading to. But it does mean an attacker who steals an npm token can't publish a malicious `sigild` under our name; they'd need to compromise the GitHub repo + push a tag, which leaves an audit trail. Every release also publishes a [CycloneDX SBOM](https://cyclonedx.org/) as a GitHub Release asset, enumerating every package (direct + transitive) in the install tree at the version pinned by `package-lock.json`: ```sh # Download + inspect the SBOM for a specific release: gh release download v0.0.4 --repo cdrn/sigil --pattern '*.cdx.json' # → produces sigild-v0.0.4.cdx.json — feed to syft/grype/etc. for vuln scan ``` ## Threat model See [THREAT_MODEL.md](https://github.com/cdrn/sigil/blob/HEAD/THREAT_MODEL.md). Read it before trusting this with anything. ## Development ```sh git clone https://github.com/cdrn/sigil cd sigil npm install # respects .npmrc ignore-scripts=true npm test # builds + runs 600+ tests; should finish in under 15s ``` See [CONTRIBUTING.md](https://github.com/cdrn/sigil/blob/HEAD/CONTRIBUTING.md) for the PR-per-layer workflow. ## License Apache License 2.0. See [LICENSE](https://github.com/cdrn/sigil/blob/HEAD/LICENSE).