MCP gateways and ChatGPT Dev Mode: what IAM teams need to know

TL;DR: ChatGPT Developer Mode can reach a local SQLite MCP server through an identity-aware reverse tunnel that handles auth, TLS and per-request policy enforcement, according to Pomerium. The core issue is not convenience but whether enterprises can expose local tools to cloud LLMs without breaking Zero Trust assumptions.

NHIMG editorial — based on content published by Pomerium: Secure SQL AI analyst, enabled by Pomerium and ChatGPT Developer Mode

By the numbers:

• 90% of IT leaders say properly managing NHIs is essential for a successful zero-trust implementation.
• Only 5.7% of organisations have full visibility into their service accounts.

Questions worth separating out

Q: How should security teams govern MCP access for cloud-hosted AI tools?

A: Security teams should govern MCP access as a request-level identity problem, not a network problem.

Q: Why do VPN-based controls fail for ChatGPT-style tool access?

A: VPNs fail because they authenticate network presence, not the specific tool request made by a cloud-hosted model.

Q: What should teams do with upstream secrets used by MCP servers?

A: Teams should treat upstream secrets as non-human identities with owners, expiry, rotation and revocation requirements.

Practitioner guidance

• Classify MCP upstream credentials as governed NHIs Inventory the OAuth tokens, certificates and API secrets that allow an LLM or MCP server to reach internal data sources.
• Enforce per-request authorisation at the gateway Require the access decision to evaluate identity, resource, operation and context for each tool invocation.
• Remove VPN dependence from AI tool access design Map every local or internal tool exposed to a cloud model and replace blanket network trust with identity-aware routing.

What's in the full article

Pomerium's full blog post covers the operational detail this post intentionally leaves for the source:

• A live walkthrough of how the reverse tunnel terminates in Pomerium and how auth, TLS and policy enforcement are wired together.
• The exact ChatGPT Developer Mode workflow used to list tables, generate SQL and render output through MCP tools.
• Configuration-level guidance for handling OAuth flows, upstream tokens and certificate management without custom server code.
• Practical examples of how the same route can be reused for local development, testing and peer sharing.

👉 Read Pomerium's analysis of secure MCP access with ChatGPT Developer Mode →

MCP gateways and ChatGPT Dev Mode: what IAM teams need to know?

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