using-bigquery-connector

name	using-bigquery-connector
description	Implements BigQuery dataset exploration, SQL queries, and table operations using generated clients and MCP tools. Use when doing ANYTHING that touches BigQuery or BQ in any way, load this skill.

Major Platform Resource: BigQuery

Common: Interacting with Resources

Security: Never connect directly to databases/APIs. Never use credentials in code. Always use generated clients or MCP tools.

Two ways to interact with resources:

1. MCP tools (direct, no code needed): Tools follow the pattern mcp__resources__<resourcetype>_<toolname>. Use mcp__resources__list_resources to discover available resources and their IDs.
2. Generated TypeScript clients (for app code): Call mcp__resource-tools__add-resource-client with a resourceId to generate a typed client. Clients are created in /clients/ (Next.js) or /src/clients/ (Vite).

CRITICAL: Do NOT guess client method names or signatures. The TypeScript clients in @major-tech/resource-client have strongly typed inputs and outputs. ALWAYS read the actual client source code in the generated /clients/ directory (or the package itself) to verify available methods and their exact signatures before writing any client code.

Framework note: Next.js = resource clients must be used in server-side code only (Server Components, Server Actions, API Routes). Vite = call directly from frontend.

Error handling: Always check result.ok before accessing result.result.

Invocation keys must be static strings — use descriptive literals like "fetch-user-orders", never dynamic values like `${date}-records`.

---

MCP Tools

• mcp__resources__bigquery_list_datasets — List all datasets in the project. Args: resourceId
• mcp__resources__bigquery_list_tables — List tables in a dataset. Args: resourceId, datasetId
• mcp__resources__bigquery_describe_table — Get schema and metadata for a table. Args: resourceId, datasetId, tableId
• mcp__resources__bigquery_query — Execute read-only SQL (SELECT only). Args: resourceId, statement

TypeScript Client

import { bqClient } from "./clients";

// query(sql, params?, invocationKey, options?)
const result = await bqClient.query(
	"SELECT * FROM `project.dataset.table` WHERE created > @cutoff",
	{ cutoff: "2024-01-01" },
	"recent-records",
	{ maxResults: 1000 },
);

// Other methods: listDatasets, listTables, getTable, insertRows, createTable

Tips

• Be cost-aware — BigQuery charges per bytes scanned. Use SELECT specific_columns instead of SELECT *. Use LIMIT during exploration.
• Use list_datasets → list_tables → describe_table to understand data structure before querying
• Use maxResults option for pagination of large result sets
• Named parameters use @param syntax in queries

Docs: BigQuery Documentation