MCP Configuration

Configuration

The hosted service handles OAuth and storage. Local stdio settings control client-side limits; requests outside a configured guard fail before DataBlue runs.

Variable	Default	Allowed
`DATABLUE_API_KEY`	Required for actions	DataBlue API key
`DATABLUE_BASE_URL`	`https://api.datablue.dev`	API origin
`DATABLUE_MCP_TIMEOUT_MS`	60000	1000-300000
`DATABLUE_MCP_MAX_RESULTS`	100	1-100
`DATABLUE_MCP_MAX_CRAWL_PAGES`	100	1-1000
`DATABLUE_MCP_MAX_RESPONSE_BYTES`	60000	2000-500000
`DATABLUE_MCP_MAX_ARRAY_ITEMS`	10	1-100
`DATABLUE_MCP_ALLOW_FULL_RESPONSE`	false	true or false

DATABLUE_MCP_MAX_RESPONSE_BYTES bounds the complete serialized MCP tool result, including the JSON text block, matching structuredContent, and an optional resource link. The inline data budget is therefore smaller than the full wire budget. DATABLUE_MCP_ALLOW_FULL_RESPONSE=true deliberately bypasses that byte limit for successful calls; use it only with a local client that can accept the duplicated full payload.

Example environment

Example

DATABLUE_API_KEY="YOUR_API_KEY"
DATABLUE_MCP_TIMEOUT_MS="90000"
DATABLUE_MCP_MAX_RESPONSE_BYTES="100000"
DATABLUE_MCP_MAX_ARRAY_ITEMS="20"

Troubleshooting

Symptom	Check
Hosted connector cannot authenticate	Reconnect the client, finish DataBlue consent, and confirm the grant under Connected apps.
Hosted grant was revoked	Run the client's MCP login again to create a new grant; revoked access and refresh tokens cannot be reused.
Local server does not start	Node.js is 18.18 or newer and `npx` can install `@datablue/mcp@latest`.
Local tool returns authentication error	`DATABLUE_API_KEY` is in the MCP server environment, not a tool argument.
Large fields are missing	Use `datablue_get_result_items` with `response.full_result.id`; use the raw URI only for lossless reconstruction.
Local client shows no tools	Restart the client and inspect the stdio server with MCP Inspector.
Local protocol output is invalid	Keep stdout reserved for MCP; send logs to stderr.