MCP authentication Overview Doc

[AnuradhaKaruppiah]

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[AnuradhaKaruppiah]

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@AnuradhaKaruppiah, I'll provide a comprehensive review of this MCP authentication documentation PR.

Overview

This PR adds excellent comprehensive documentation for MCP OAuth2 authentication in the NeMo Agent toolkit. The structure is logical and covers both conceptual and practical aspects well.

Strengths

✅ Clear progression from concepts to configuration to examples
✅ Well-structured with appropriate headings and code blocks
✅ Includes both single-user and multi-user workflow examples
✅ Good use of Mermaid diagrams to visualize authentication flows
✅ Security considerations and troubleshooting sections included
✅ Proper cross-referencing with existing MCP documentation

Issues and Suggestions

1. Empty Placeholder File

📁 docs/examples/MCP/simple_auth_mcp/README.md is completely empty. This should either:

• Be removed if not needed yet
• Contain actual content
• Have a comment explaining it's a placeholder

2. Documentation Location Inconsistency

The example README at examples/MCP/simple_auth_mcp/README.md references:

It is recommended to read the [MCP Authentication](../../../docs/source/workflows/mcp/mcp-auth.md) documentation first.

However, there's also an empty file at docs/examples/MCP/simple_auth_mcp/README.md. Should these be:

• The same file (symlink)?
• Different files with different purposes?
• Only one of them?

3. Minor Typos and Grammar

Line 41 in mcp-auth.md:

- `default_user_id`: The user ID for setting discovering and adding tools

Should be:

- `default_user_id`: The user ID for discovering and adding tools

4. Configuration Example Inconsistency

In the first configuration example (line 31-37), you use:

authentication:
  auth_provider_mcp:
    _type: mcp_oauth2

But in the detailed example (line 88-94), you use:

authentication:
  mcp_oauth2_jira:
    _type: mcp_oauth2

Consider clarifying the naming convention or using consistent names throughout to avoid confusion.

5. Mermaid Diagram Enhancement

The multi-user diagram could be clearer. Consider adding styling or notes to distinguish the default user flow from UI user flows:

flowchart LR
  U0[User<br/>default-user-id<br/><i>setup only</i>] --> H2[MCP Host<br/>NAT Workflow]
  U1[User<br/>UI-User-1] --> H2
  U2[User<br/>UI-User-2] --> H2

Loading

6. Missing Information

The documentation could benefit from:

• Token refresh behavior: How are tokens refreshed? What happens when they expire?
• Concurrent user limits: Are there any limits on concurrent authenticated users?
• Token storage: Where are tokens cached? What are the security implications?

7. Example Configuration Path

Line 77 references:

The MCP Authentication Example Workflow, `examples/MCP/simple_auth_mcp/README.md`

But that file doesn't contain the workflow itself. Should this reference a YAML config file instead? Or clarify what users should expect to find there?

8. Environment Variable Documentation

Lines 51-59 document environment variables, but it would be helpful to also mention:

• What happens if NAT_USER_ID is not set (you mention it defaults to server_url, but this could be more prominent)
• Whether these can be set in a .env file
• Whether they can be overridden in the YAML config

9. Troubleshooting Section Enhancement

The troubleshooting section (lines 169-176) could include:

• How to clear cached credentials
• How to re-authenticate a user
• Common OAuth2 error messages and their meanings

Technical Accuracy

✅ OAuth2 flow description is correct
✅ RFC references are accurate
✅ Configuration syntax matches NeMo Agent toolkit patterns
✅ Transport limitations are correctly stated

Formatting

The documentation follows proper Markdown formatting with one minor suggestion:

Line 170:

1. If setup fails, the user identified by `default_user_id` did not complete the authentication flow through the pop-up UI, or the user did not authorize the workflow to access the MCP server.

This could be split into sub-bullets for better readability:

1. **Setup fails** - This can happen if:
   - The user identified by `default_user_id` did not complete the authentication flow through the pop-up UI, or
   - The user did not authorize the workflow to access the MCP server

Summary

This is solid documentation that will be very helpful for users implementing MCP authentication. The main action items are:

1. ⚠️ Critical: Address the empty docs/examples/MCP/simple_auth_mcp/README.md file
2. Fix the typo on line 41 ("setting discovering" → "discovering")
3. Consider the enhancement suggestions for clarity

Would you like me to help generate any additional content for the example README files or provide more detailed configuration examples?

[willkill07]

Just one nit! otherwise LGTM

[AnuradhaKaruppiah]

/merge