@purplesquirrel/mcp-core-ts

Shared MCP server infrastructure for TypeScript. Mirror of psm-mcp-core (Rust).

Modules

| Module | What it does | |--------|-------------| | error | PsmMcpError (10 variants, JSON-RPC codes), sanitizeError() | | input | validateNoInjection(), validateName(), requireString(), optionalString() | | tool | ToolHandler, McpAction, textResult(), jsonResult(), errorResult() | | filter | OutputFilter — 9 secret patterns + 4 PII patterns | | health | HealthCheck, healthy(), degraded(), unhealthy() | | audit | AuditLogger — in-memory FIFO, max 50K entries | | rate-limit | RateLimiter — sliding window, per-key | | policy | PolicyEnforcer — 5 default rules (SQLi, XXE, path traversal, command injection, secrets) | | shell | runCommand() with timeout, shellEscape(), stripAnsi() |

Install

npm install @purplesquirrel/mcp-core-ts
# or local:
npm install --save file:../psm-mcp-core-ts

Usage

import {
  requireString, validateNoInjection, sanitizeError,
  textResult, errorResult, OutputFilter,
} from "@purplesquirrel/mcp-core-ts";

// In your tool handler:
const name = requireString(args, "name");
validateNoInjection(name, "name");

// Filter output:
const filter = new OutputFilter();
const result = filter.filter(apiResponse);

// Error handling:
catch (err) {
  return errorResult(sanitizeError(err.message));
}

Tests

npm test          # 117 tests (63 core + 54 shared vectors)
npm run check:types

Shared test vectors in tests/shared-vectors.json run identically in both TypeScript and Rust.