fix(skill-mcp): redact sensitive data from connection errors

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/skill-mcp-manager/error-redaction.ts

@@ -0,0 +1,47 @@
+// Redacts sensitive tokens from error messages to prevent credential exposure
+// Follows same patterns as env-cleaner.ts for consistency
+
+const SENSITIVE_PATTERNS: RegExp[] = [
+  // API keys and tokens in common formats
+  /[a-zA-Z0-9_-]*(?:api[_-]?key|apikey)["\s]*[:=]["\s]*([a-zA-Z0-9_-]{16,})/gi,
+  /[a-zA-Z0-9_-]*(?:auth[_-]?token|authtoken)["\s]*[:=]["\s]*([a-zA-Z0-9_-]{16,})/gi,
+  /[a-zA-Z0-9_-]*(?:access[_-]?token|accesstoken)["\s]*[:=]["\s]*([a-zA-Z0-9_-]{16,})/gi,
+  /[a-zA-Z0-9_-]*(?:secret)["\s]*[:=]["\s]*([a-zA-Z0-9_-]{16,})/gi,
+  /[a-zA-Z0-9_-]*(?:password)["\s]*[:=]["\s]*([a-zA-Z0-9_-]{8,})/gi,
+
+  // Bearer tokens
+  /bearer\s+([a-zA-Z0-9_-]{20,})/gi,
+
+  // Common token prefixes
+  /sk-[a-zA-Z0-9]{20,}/g, // OpenAI-style secret keys
+  /gh[pousr]_[a-zA-Z0-9]{20,}/gi, // GitHub tokens
+  /glpat-[a-zA-Z0-9_-]{20,}/gi, // GitLab tokens
+  /[A-Za-z0-9_]{20,}-[A-Za-z0-9_]{10,}-[A-Za-z0-9_]{10,}/g, // Common JWT-like patterns
+]
+
+const REDACTION_MARKER = "[REDACTED]"
+
+/**
+ * Redacts sensitive tokens from a string.
+ * Used for error messages that may contain command-line arguments or environment info.
+ */
+export function redactSensitiveData(input: string): string {
+  let result = input
+
+  for (const pattern of SENSITIVE_PATTERNS) {
+    result = result.replace(pattern, REDACTION_MARKER)
+  }
+
+  return result
+}
+
+/**
+ * Redacts sensitive data from an Error object, returning a new Error.
+ * Preserves the stack trace but redacts the message.
+ */
+export function redactErrorSensitiveData(error: Error): Error {
+  const redactedMessage = redactSensitiveData(error.message)
+  const redactedError = new Error(redactedMessage)
+  redactedError.stack = error.stack ? redactSensitiveData(error.stack) : undefined
+  return redactedError
+}

src/features/skill-mcp-manager/stdio-client.ts

@@ -3,6 +3,7 @@ import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js"
 import type { ClaudeCodeMcpServer } from "../claude-code-mcp-loader/types"
 import { createCleanMcpEnvironment } from "./env-cleaner"
 import { registerProcessCleanup, startCleanupTimer } from "./cleanup"
+import { redactSensitiveData } from "./error-redaction"
 import type { ManagedClient, SkillMcpClientConnectionParams } from "./types"
 
 function getStdioCommand(config: ClaudeCodeMcpServer, serverName: string): string {
@@ -45,10 +46,13 @@ export async function createStdioClient(params: SkillMcpClientConnectionParams):
     }
 
     const errorMessage = error instanceof Error ? error.message : String(error)
+    const fullCommand = `${command} ${args.join(" ")}`
+    const safeCommand = redactSensitiveData(fullCommand)
+    const safeErrorMessage = redactSensitiveData(errorMessage)
     throw new Error(
       `Failed to connect to MCP server "${info.serverName}".\n\n` +
-      `Command: ${command} ${args.join(" ")}\n` +
-      `Reason: ${errorMessage}\n\n` +
+      `Command: ${safeCommand}\n` +
+      `Reason: ${safeErrorMessage}\n\n` +
       `Hints:\n` +
       `  - Ensure the command is installed and available in PATH\n` +
       `  - Check if the MCP server package exists\n` +