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How are you handling API keys with Claude Code and MCP servers?

Reddit · jsherer · May 5, 2026
A developer built Factorly, an open-source tool to secure API keys and credentials used with Claude Code and MCP servers by encrypting them in a vault instead of storing them in plaintext configuration files. The tool sits between Claude Code and various services, restricting Claude's access to tool names and results while keeping credentials hidden, and supports per-tool policies and chained workflows for automated tasks requiring approval at certain steps. Factorly runs locally, is written in Go, and addresses the security concern of plaintext credential storage in MCP server setups.

Detailed Analysis

A security concern emerging from the rapid adoption of Claude Code and Model Context Protocol (MCP) servers has prompted at least one developer to build and release an open-source credential management layer called Factorly. The problem, as described in a community discussion on Reddit's r/ClaudeAI, stems from the architectural reality of how MCP servers are typically configured: API keys, OAuth tokens, and database passwords are stored in plaintext configuration files that Claude can directly read. The developer, uncomfortable with this exposure, used Claude Code as a collaborative development partner to build Factorly — a Go-based tool that runs locally and acts as an intermediary layer between Claude Code and any connected MCP servers, REST APIs, or CLI tools. Credentials are stored in an encrypted vault, and Claude only ever receives tool names and results, never the underlying secrets.

Beyond credential isolation, Factorly introduces a policy enforcement mechanism that allows operators to assign per-tool rules — allow, confirm, deny, or rate-limit — to each tool call Claude might attempt. The tool also supports chained workflows, a feature designed for scenarios like incident triage, where some automated steps are acceptable but high-stakes actions — such as posting to Slack or triggering external notifications — require explicit human confirmation before execution. This reflects a more nuanced model of human-in-the-loop oversight, where trust is not binary but graduated based on the sensitivity or irreversibility of individual actions.

The concern raised in this post touches on a structural gap that has accompanied the rapid, somewhat ad hoc expansion of the MCP ecosystem. MCP, Anthropic's open protocol for connecting AI models to external tools and data sources, has seen widespread third-party adoption since its introduction, with developers building servers for everything from database access to cloud infrastructure management. The default implementation pattern — storing credentials in local config files — was optimized for ease of setup rather than security hygiene, and as Claude Code has grown more capable of autonomously executing multi-step tasks, the blast radius of a compromised or misbehaving session has grown correspondingly larger.

The emergence of community-built tooling like Factorly signals a maturation phase in the agentic AI developer ecosystem, where early adopters are beginning to identify and patch the security assumptions baked into first-generation toolchains. This mirrors patterns seen in the early DevOps and cloud-native movements, where the initial velocity of adoption consistently outpaced security best practices, eventually prompting both community solutions and vendor-level responses. The fact that Factorly itself was built with Claude Code as a development partner adds a layer of recursive significance — the same tool whose credential-handling raised concerns was used to engineer its own mitigation.

More broadly, the discussion reflects a growing industry conversation about what responsible agentic AI deployment looks like at the individual developer level, outside of enterprise security perimeters. As Claude and similar models are increasingly used to drive autonomous workflows with real-world side effects — committing code, querying databases, interacting with external services — the question of what the model should be allowed to see, and under what conditions it should act without confirmation, becomes operationally critical. Projects like Factorly suggest that the developer community is not waiting for top-down solutions and is instead converging on open-source middleware as a pragmatic bridge between the capabilities of current AI tooling and the security standards those capabilities demand.

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