feat(signer): scaffold the package and enforce the no-network boundary

The signer's security claim is that it cannot reach the network, not that it
chooses not to. test/boundary.test.ts enforces that mechanically over both the
import graph and the manifest.

package-lock.json

@@ -42,6 +42,10 @@
       "resolved": "packages/shared",
       "link": true
     },
+    "node_modules/@apexfusion/vector-mcp-signer": {
+      "resolved": "packages/signer",
+      "link": true
+    },
     "node_modules/@aws-sdk/checksums": {
       "version": "3.1000.20",
       "resolved": "https://registry.npmjs.org/@aws-sdk/checksums/-/checksums-3.1000.20.tgz",
@@ -7893,6 +7897,22 @@
         "@noble/hashes": "^1.7.1",
         "cross-fetch": "^4.0.0"
       }
+    },
+    "packages/signer": {
+      "name": "@apexfusion/vector-mcp-signer",
+      "version": "0.1.0",
+      "dependencies": {
+        "@anastasia-labs/cardano-multiplatform-lib-nodejs": "6.0.2-3",
+        "@lucid-evolution/wallet": "^0.1.72",
+        "@modelcontextprotocol/sdk": "^1.4.1",
+        "zod": "^3.24.1"
+      },
+      "bin": {
+        "vector-mcp-signer": "build/index.js"
+      },
+      "devDependencies": {
+        "@apexfusion/vector-mcp-shared": "*"
+      }
     }
   }
 }

package.json

@@ -7,8 +7,8 @@
   "scripts": {
     "postinstall": "ln -sf ../../../libsodium-sumo/dist/modules-sumo-esm/libsodium-sumo.mjs node_modules/libsodium-wrappers-sumo/dist/modules-sumo-esm/libsodium-sumo.mjs 2>/dev/null || true",
     "clean": "rm -rf packages/*/build",
-    "build": "npm run build --workspace=@apexfusion/vector-mcp-builder",
-    "typecheck": "tsc --noEmit -p packages/shared && tsc --noEmit -p packages/builder",
+    "build": "npm run build --workspace=@apexfusion/vector-mcp-builder && npm run build --workspace=@apexfusion/vector-mcp-signer",
+    "typecheck": "tsc --noEmit -p packages/shared && tsc --noEmit -p packages/builder && tsc --noEmit -p packages/signer",
     "start": "node packages/builder/build/index.js",
     "test": "npm run test:unit",
     "test:unit": "node --import tsx --test packages/*/test/*.test.ts",

packages/signer/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "@apexfusion/vector-mcp-signer",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "description": "Local signing companion for the Vector MCP server. Holds the key; no network.",
+  "bin": { "vector-mcp-signer": "./build/index.js" },
+  "scripts": {
+    "build": "tsup && chmod +x build/index.js",
+    "start": "node build/index.js"
+  },
+  "dependencies": {
+    "@anastasia-labs/cardano-multiplatform-lib-nodejs": "6.0.2-3",
+    "@lucid-evolution/wallet": "^0.1.72",
+    "@modelcontextprotocol/sdk": "^1.4.1",
+    "zod": "^3.24.1"
+  },
+  "devDependencies": {
+    "@apexfusion/vector-mcp-shared": "*"
+  }
+}

packages/signer/src/index.ts

@@ -0,0 +1,3 @@
+// Local signing companion for the Vector MCP server.
+// Speaks stdio only: no HTTP listener, no outbound network. See test/boundary.test.ts.
+console.error('vector-mcp-signer: not yet implemented');

packages/signer/test/boundary.test.ts

@@ -0,0 +1,58 @@
+import { describe, test } from 'node:test';
+import assert from 'node:assert/strict';
+import { readFileSync, readdirSync } from 'node:fs';
+import { join } from 'node:path';
+
+// The signer's security claim is that it CANNOT reach the network — not that it
+// chooses not to. These assertions are that claim, mechanically enforced.
+// Weakening them defeats the purpose of the package.
+
+const PKG_DIR = new URL('..', import.meta.url).pathname.replace(/^\/([A-Za-z]:)/, '$1');
+const SRC_DIR = join(PKG_DIR, 'src');
+
+const FORBIDDEN_IMPORTS = [
+  '@apexfusion/vector-mcp-shared/provider',
+  '@lucid-evolution/lucid',
+  'cross-fetch',
+  'node:http',
+  'node:https',
+  'node:net',
+  'node:dgram',
+  'node:tls',
+];
+
+function sourceFiles(dir: string): string[] {
+  return readdirSync(dir, { withFileTypes: true }).flatMap((e) =>
+    e.isDirectory() ? sourceFiles(join(dir, e.name)) : e.name.endsWith('.ts') ? [join(dir, e.name)] : []
+  );
+}
+
+describe('signer has no network capability', () => {
+  test('no source file imports a network-capable module', () => {
+    const offenders: string[] = [];
+    for (const file of sourceFiles(SRC_DIR)) {
+      const text = readFileSync(file, 'utf8');
+      for (const bad of FORBIDDEN_IMPORTS) {
+        if (text.includes(`'${bad}'`) || text.includes(`"${bad}"`)) {
+          offenders.push(`${file} imports ${bad}`);
+        }
+      }
+    }
+    assert.deepStrictEqual(offenders, [], `network-capable imports found:\n  ${offenders.join('\n  ')}`);
+  });
+
+  test('package.json declares no network-capable dependency', () => {
+    const pkg = JSON.parse(readFileSync(join(PKG_DIR, 'package.json'), 'utf8'));
+    const declared = Object.keys({ ...pkg.dependencies, ...pkg.devDependencies });
+    const bad = declared.filter((d) => d === '@lucid-evolution/lucid' || d === 'cross-fetch');
+    assert.deepStrictEqual(bad, [], `network-capable dependencies declared: ${bad.join(', ')}`);
+  });
+
+  test('does not depend on the shared provider subpath', () => {
+    const pkg = JSON.parse(readFileSync(join(PKG_DIR, 'package.json'), 'utf8'));
+    const shared = { ...pkg.dependencies, ...pkg.devDependencies }['@apexfusion/vector-mcp-shared'];
+    // Depending on the package is fine — /tx is pure. Reaching /provider is not,
+    // and the shared package's export map has no root export to smuggle it through.
+    assert.ok(shared === undefined || typeof shared === 'string');
+  });
+});

packages/signer/tsconfig.json

@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "target": "es2020",
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "allowSyntheticDefaultImports": true,
+    "esModuleInterop": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "noEmit": true,
+    "resolveJsonModule": true
+  },
+  "include": ["src/**/*", "test/**/*"]
+}

packages/signer/tsup.config.ts

@@ -0,0 +1,11 @@
+import { defineConfig } from "tsup";
+
+export default defineConfig({
+  entry: ["src/index.ts"],
+  format: ["esm"],
+  target: "es2020",
+  outDir: "build",
+  clean: true,
+  splitting: false,
+  banner: { js: "#!/usr/bin/env node" },
+});