feat: add mcp_servers field to app manifest

[zimeg]

Changelog

The mcp_server manifest fields are supported for connecting MCP servers to Slack.

Summary

This pull request adds the mcp_servers field to the app manifest struct, so apps can make MCP server connections available.

Supported fields:

• url: Required. HTTPS endpoint of the MCP server
• auth_provider_key: Optional. Reference to an external_auth_providers entry for OAuth
• auth_type: Required. Authentication method - no_auth, slack_identity_auth, manual_auth, or dynamic_client_registration

Schema definition: slackapi/manifest-schema#71

Testing

With the mcp:connect scope included please confirm the following manifests are installed as expected or that all values appear with:

$ slack manifest

No authentication

{
  "display_information": {
    "name": "MCP Docs Server",
    "description": "Serves public Slack documentation from MCP"
  },
  "features": {
    "bot_user": {
      "display_name": "MCP Docs Server",
      "always_online": true
    }
  },
  "oauth_config": {
    "scopes": {
      "bot": ["mcp:connect"]
    }
  },
  "settings": {
    "org_deploy_enabled": true,
    "socket_mode_enabled": false,
    "token_rotation_enabled": false
  },
  "mcp_servers": {
    "docs": {
      "url": "https://88bf-170-39-168-237.ngrok-free.app/mcp",
      "auth_type": "no_auth"
    }
  }
}

Slack-identity authentication

{
  "display_information": {
    "name": "MCP Profile Card",
    "description": "Looks up Slack user profiles using Slack identity auth"
  },
  "features": {
    "app_home": {},
    "bot_user": {
      "display_name": "MCP Profile Card",
      "always_online": true
    }
  },
  "oauth_config": {
    "redirect_urls": [
      "https://88bf-170-39-168-237.ngrok-free.app/slack/oauth_redirect"
    ],
    "scopes": {
      "bot": [
        "mcp:connect",
        "users:read",
        "users:read.email"
      ]
    }
  },
  "settings": {
    "socket_mode_enabled": false,
    "org_deploy_enabled": true,
    "token_rotation_enabled": false
  },
  "mcp_servers": {
    "profile": {
      "url": "https://88bf-170-39-168-237.ngrok-free.app/mcp",
      "auth_type": "slack_identity_auth"
    }
  }
}

Standard OAuth handshakes

{
  "display_information": {
    "name": "MCP GitHub Server",
    "description": "Connects to GitHub with External Auth Provider"
  },
  "features": {
    "app_home": {},
    "bot_user": {
      "display_name": "MCP GitHub Server",
      "always_online": true
    }
  },
  "oauth_config": {
    "scopes": {
      "bot": [
        "mcp:connect"
      ]
    }
  },
  "settings": {
    "socket_mode_enabled": false,
    "org_deploy_enabled": true,
    "token_rotation_enabled": false
  },
  "external_auth_providers": {
    "oauth2": {
      "github": {
        "provider_type": "CUSTOM",
        "options": {
          "client_id": "YOUR_GITHUB_CLIENT_ID",
          "scope": [],
          "provider_name": "GitHub",
          "authorization_url": "https://github.com/login/oauth/authorize",
          "token_url": "https://github.com/login/oauth/access_token",
          "identity_config": {
            "url": "https://api.github.com/user",
            "account_identifier": "$.login"
          },
          "use_pkce": false,
          "token_url_config": {
            "use_basic_auth_scheme": false
          }
        }
      }
    }
  },
  "mcp_servers": {
    "github": {
      "url": "https://api.githubcopilot.com/mcp/",
      "auth_provider_key": "github",
      "auth_type": "manual_auth"
    }
  }
}

Dynamic client registration

{
  "display_information": {
    "name": "MCP Notion Server",
    "description": "Connects to Notion with Dynamic Client Registration"
  },
  "features": {
    "bot_user": {
      "display_name": "MCP Notion Server",
      "always_online": true
    }
  },
  "oauth_config": {
    "scopes": {
      "bot": ["mcp:connect"]
    }
  },
  "settings": {
    "org_deploy_enabled": true,
    "socket_mode_enabled": false,
    "token_rotation_enabled": false
  },
  "mcp_servers": {
    "notion": {
      "url": "https://mcp.notion.com/mcp",
      "auth_type": "dynamic_client_registration"
    }
  }
}

Notes

• The external_auth_providers field already exists and mcp_servers references auth_provider_key using these values
• The use_pkce and token_url_config fields added in the schema PR are already supported here since oauth2 provider options use a passthrough *RawJSON value

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.66%. Comparing base (e37243b) to head (1538e8e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #580      +/-   ##
==========================================
+ Coverage   71.64%   71.66%   +0.02%     
==========================================
  Files         226      226              
  Lines       19148    19148              
==========================================
+ Hits        13718    13723       +5     
+ Misses       4221     4218       -3     
+ Partials     1209     1207       -2     

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[srtaalej]

looks great!! mcp_servers serializing correctly ⭐