FlowiseAI/Flowise · error · Error

Missing Slack credentials. Provide either an OAuth2 access t

Error message

Missing Slack credentials. Provide either an OAuth2 access token or a Bot Token with Team ID.

What it means

Thrown by SlackMCP.getTools when neither credential path is satisfied: there is no OAuth2 access_token AND there is no (botToken + teamId) pair. The node supports either an OAuth2 token (HTTP transport to mcp.slack.com/mcp) or a Bot Token + Team ID (stdio transport via @modelcontextprotocol/server-slack), and at least one complete set is required.

Source

Thrown at packages/components/nodes/tools/MCP/Slack/SlackMCP.ts:127

                    }
                },
                'http'
            )
        } else if (botToken && teamId) {
            const packagePath = getNodeModulesPackagePath('@modelcontextprotocol/server-slack/dist/index.js')

            const serverParams = {
                command: 'node',
                args: [packagePath],
                env: {
                    SLACK_BOT_TOKEN: botToken,
                    SLACK_TEAM_ID: teamId
                }
            }

            toolkit = new MCPToolkit(serverParams, 'stdio')
        } else {
            throw new Error('Missing Slack credentials. Provide either an OAuth2 access token or a Bot Token with Team ID.')
        }

        await toolkit.initialize()

        const tools = toolkit.tools ?? []

        return tools as Tool[]
    }
}

module.exports = { nodeClass: Slack_MCP }

View on GitHub (pinned to abe4a8601a)

Solutions

Choose one auth method: OAuth2 (provide access_token) OR Bot Token (provide BOTH botToken and teamId).
For Bot Token mode, obtain the Team ID (T-prefixed ID) from Slack and fill both botToken and teamId.
For OAuth2, ensure access_token is present (the code also accepts the 'accessToken' alias and refreshes it).
Re-bind the corrected credential and retry.

Example fix

// OAuth2 path (HTTP):
//   credential.access_token = 'xoxb-...'
// Bot Token path (stdio):
//   credential.botToken = 'xoxb-...'
//   credential.teamId   = 'T12345'

Defensive patterns

Strategy: validation

Validate before calling

const credentialData = await getCredentialData(nodeData.credential ?? '', options)
const accessToken = getCredentialParam('access_token', credentialData, nodeData) || getCredentialParam('accessToken', credentialData, nodeData)
const botToken = getCredentialParam('botToken', credentialData, nodeData)
const teamId = getCredentialParam('teamId', credentialData, nodeData)
const ok = !!accessToken || (!!botToken && !!teamId)
if (!ok) throw new Error('Missing Slack credentials')

Type guard

type SlackCred = { access_token?: string; botToken?: string; teamId?: string }
function hasCompleteSlackCred(c: SlackCred): boolean {
    return (!!c.access_token && c.access_token.trim().length > 0)
        || (!!c.botToken && c.botToken.trim().length > 0 && !!c.teamId && c.teamId.trim().length > 0)
}

Try / catch

try { await slackMcp.getTools(nodeData, options) }
catch (e) { if (e instanceof Error && e.message.startsWith('Missing Slack credentials')) { /* guide user to OAuth2 OR botToken+teamId */ } }

Prevention

Validate the credential at save time so partial entries cannot be stored.
Document the two supported auth modes clearly on the credential component.
Make teamId required when botToken is present (conditional required-field validation).

When it happens

Trigger: Calling getTools with a Slack credential that has no access_token, or has a botToken but no teamId (or vice versa), or a completely empty credential.

Common situations: User intended OAuth2 but only entered a bot token; entered bot token but forgot Team ID; credential created but no fields filled; mixed fields from two auth methods incompletely.

Related errors

AI-assisted analysis of FlowiseAI/Flowise@abe4a8601a (2026-08-12). Data as JSON: /api/errors/4b2762e86332ff0e. Report an issue: GitHub.