Support custom headers for remote MCP server connections

[vancexu]

Problem Statement

When connecting to a remote MCP server that uses end-to-end encryption, the server needs a passphrase via a custom header (e.g., X-E2E-Passphrase) to decrypt user data. Currently, claude.ai's "Add custom connector" UI only supports OAuth for authentication — there's no way to configure custom HTTP headers sent with each MCP request.

This means users with E2E-encrypted MCP servers cannot use claude.ai to access their decrypted data, even though they can authenticate fine via OAuth. Their encrypted fields display as [Encrypted] because the passphrase cannot be transmitted.

Proposed Solution

Add an optional "Custom Headers" section to the custom connector settings, allowing users to define key-value pairs that are sent with every request to the remote MCP
server. For example:

Header Name: X-E2E-Passphrase
Header Value: ••••••••••••

Values should be treated as secrets (masked in UI, stored securely).

Alternatives Considered

No way to work around this.
Claude Code mcp doesn't have this problem because the mcp config can use env to specify such custom headers.

Area

MCP Connector (adding/managing servers)

Priority

Critical - Blocking my MCP server development

Additional Context

No response

[localden]

Thank you for taking the time to report this — it's helpful feedback. We're currently triaging open MCP issues, and this one is being closed in favor of tracking the suggestion in #10, which covers the same request (custom header / static credential auth for remote MCP connectors). Please follow that issue for updates and feel free to add any additional context there.