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caron14

BigQuery Validator

by caron14

mcp-bigquery

Model Context Protocol을 통한 안전한 BigQuery 탐색

MIT License PyPI Version Python Support Downloads

문서 | 빠른 시작 | 사용 예시


개요

mcp-bigquery는 AI 어시스턴트(예: Claude)가 Google BigQuery와 안전하게 상호작용할 수 있도록 하는 Model Context Protocol(MCP) 서버입니다.

주요 기능

  • 안전한 실행: 모든 작업은 엄격히 dry-run 검증으로 제한됩니다. 서버는 데이터를 변경하거나 실행 비용이 발생하는 쿼리를 절대 실행하지 않습니다.

  • 비용 투명성: 실행 전에 쿼리 비용과 처리 바이트 수의 추정치를 제공합니다.

  • 정적 분석: 쿼리 종속성을 분석하고 SQL 구문을 검증합니다.

  • 스키마 탐색: 데이터셋, 테이블, 컬럼을 탐색합니다.

비즈니스 가치

문제

mcp-bigquery를 사용한 해결 방안

비용이 많이 드는 쿼리의 의도하지 않은 실행

실행 전 비용 추정

SQL 구문 오류로 인한 개발 지연

조기 구문 오류 감지

스키마 구조에 대한 가시성 부족

안전한 스키마 메타데이터 탐색

AI에 의한 무단 데이터 변경 위험

강제된 dry-run 제약 조건


Related MCP server: BigQuery MCP Server

빠른 시작

1단계: 설치

pip를 통해 패키지를 설치합니다:

pip install mcp-bigquery

2단계: 인증

Google Cloud Platform 인증을 설정합니다:

# For user account authentication
gcloud auth application-default login

# For service account authentication
export GOOGLE_APPLICATION_CREDENTIALS=/path/to/key.json

3단계: Claude Desktop 구성

Claude Desktop 구성 파일에서 서버를 구성합니다:

  • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

  • Windows: %APPDATA%\Claude\claude_desktop_config.json

다음 항목을 추가합니다:

{
  "mcpServers": {
    "mcp-bigquery": {
      "command": "mcp-bigquery",
      "env": {
        "BQ_PROJECT": "your-gcp-project-id"
      }
    }
  }
}

4단계: 검증

Claude Desktop을 다시 시작하고 다음 쿼리를 실행하여 설정을 확인합니다:

  • "내 BigQuery 프로젝트에서 사용할 수 있는 데이터셋은 무엇인가요?"

  • "다음 쿼리의 비용을 추정할 수 있나요: SELECT * FROM dataset.table"

  • "users 테이블의 스키마를 보여주세요"


사용 가능한 도구

SQL 검증 및 분석

도구

용도

주요 사용 사례

bq_validate_sql

SQL 구문 확인

쿼리 실행 전 검증

bq_dry_run_sql

비용 추정치 및 메타데이터 검색

실행 전 비용 평가

bq_extract_dependencies

테이블 종속성 매핑

데이터 계보 및 종속성 매핑

bq_validate_query_syntax

상세 구문 분석

복잡한 SQL 쿼리 디버깅

스키마 탐색

도구

용도

주요 사용 사례

bq_list_datasets

프로젝트의 모든 데이터셋 나열

초기 프로젝트 탐색

bq_list_tables

파티셔닝 메타데이터가 있는 테이블 나열

데이터셋 구조 탐색

bq_describe_table

상세 스키마 정보 가져오기

컬럼 수준 검증

bq_get_table_info

포괄적인 메타데이터 검색

테이블 통계 분석

bq_preview_table

테이블 데이터 미리보기(무비용)

데이터 스캔 비용 없이 샘플 레코드 확인

[!IMPORTANT] bq_preview_table 도구는 client.list_rows(API: tabledata.list)를 사용하여 샘플 행을 직접 검색하므로 스캔되는 바이트가 0이고 실행 비용이 발생하지 않습니다. 민감한 정보(예: PII)가 LLM에 의도치 않게 노출되는 것을 방지하기 위해 이 도구는 기본적으로 비활성화되어 있습니다. 환경 구성에서 MCP_BQ_ENABLE_PREVIEW=true를 설정하여 명시적으로 옵트인해야 합니다.


구성

환경 변수

변수

용도

기본값

BQ_PROJECT

대상 GCP 프로젝트 ID

ADC를 통해 결정됨

BQ_LOCATION

대상 BigQuery 리전

설정 안 됨

SAFE_PRICE_PER_TIB

비용 추정에 사용되는 TiB당 가격

5.0

LOG_LEVEL

로깅 상세 수준(DEBUG, INFO, WARNING, ERROR, CRITICAL)

WARNING

MCP_BQ_ENABLE_PREVIEW

bq_preview_table 도구 활성화(true/false)

false

.env 파일 예시

로컬 테스트 또는 개발 환경에서 .env 파일에 다음 변수를 정의할 수 있습니다:

BQ_PROJECT=your-gcp-project-id
BQ_LOCATION=asia-northeast1
SAFE_PRICE_PER_TIB=5.0
LOG_LEVEL=WARNING
MCP_BQ_ENABLE_PREVIEW=true

전체 Claude Desktop 구성 예시

{
  "mcpServers": {
    "mcp-bigquery": {
      "command": "mcp-bigquery",
      "env": {
        "BQ_PROJECT": "my-production-project",
        "BQ_LOCATION": "asia-northeast1",
        "SAFE_PRICE_PER_TIB": "6.0",
        "LOG_LEVEL": "WARNING",
        "MCP_BQ_ENABLE_PREVIEW": "true"
      }
    }
  }
}

문제 해결

오류 유형별 해결 방법

인증 오류

Error: Could not automatically determine credentials
  • 해결 방법: 명령줄을 사용하여 다시 인증합니다:

    gcloud auth application-default login

권한 거부

Error: User does not have bigquery.tables.get permission
  • 해결 방법: 대상 ID에 BigQuery Data Viewer 역할을 부여합니다:

    gcloud projects add-iam-policy-binding YOUR_PROJECT \
      --member="user:your-email@example.com" \
      --role="roles/bigquery.dataViewer"

프로젝트 ID 누락

Error: Project ID is required
  • 해결 방법: 구성에서 BQ_PROJECT 변수가 올바르게 설정되어 있는지 확인합니다.


사용 예시

예시 1: 실행 전 비용 확인

# Before running an expensive query...
query = "SELECT * FROM `bigquery-public-data.github_repos.commits`"

# First, check the cost
result = bq_dry_run_sql(sql=query)
print(f"Estimated cost: ${result['usdEstimate']}")
print(f"Data processed: {result['totalBytesProcessed'] / 1e9:.2f} GB")

# Output:
# Estimated cost: $12.50
# Data processed: 2500.00 GB

예시 2: 테이블 구조 이해

# Check table schema
result = bq_describe_table(
    dataset_id="your_dataset",
    table_id="users"
)

# Output:
# ├── user_id (INTEGER, REQUIRED)
# ├── email (STRING, NULLABLE)
# ├── created_at (TIMESTAMP, REQUIRED)
# └── profile (RECORD, REPEATED)
#     ├── name (STRING)
#     └── age (INTEGER)

예시 3: 데이터 종속성 추적

# Understand query dependencies
query = """
WITH user_stats AS (
  SELECT user_id, COUNT(*) as order_count
  FROM orders
  GROUP BY user_id
)
SELECT u.name, s.order_count
FROM users u
JOIN user_stats s ON u.id = s.user_id
"""

result = bq_extract_dependencies(sql=query)

# Output:
# Tables: ['orders', 'users']
# Columns: ['user_id', 'name', 'id']
# Dependency Graph:
#   orders → user_stats → final_result
#   users → final_result

프로젝트 상태 및 버전 이력

버전

릴리스 날짜

변경 사항 요약

v0.7.1

2026-08-17

mcp 종속성 제약 조건을 개선하고 wiki 문서를 간소화했습니다.

v0.7.0

2026-06-21

무비용 테이블 미리보기 도구(bq_preview_table) 및 보안 옵트인 구성을 추가했습니다.

v0.6.0

2026-06-21

스레드 안전 캐싱, 재귀적 AST 쿼리, 백오프 재시도 및 Google API 예외 매핑

v0.5.0

2026-01-02

포맷터 통합, 클라이언트 캐시 및 로깅 제어 통합

v0.4.2

2025-12-08

모듈식 스키마 탐색기 및 통합 클라이언트/로깅 제어

v0.4.1

2025-01-22

오류 처리 및 디버그 로깅 개선

v0.4.0

2025-01-22

스키마 탐색 도구 추가

v0.3.0

2025-01-17

SQL 정적 분석 엔진 통합

v0.2.0

2025-01-16

기본 검증 및 dry-run 쿼리를 지원하는 초기 릴리스


개발 및 기여

로컬 개발 환경 설정 및 기여 정책에 대한 지침은 CONTRIBUTING.md 가이드를 참조하세요.

# Clone the repository
git clone https://github.com/caron14/mcp-bigquery.git
cd mcp-bigquery

# Install development dependencies
pip install -e ".[dev]"

# Execute the test suite
pytest tests/

라이선스

이 프로젝트는 MIT 라이선스에 따라 라이선스가 부여됩니다. 자세한 내용은 LICENSE를 참조하세요.

Available Tools

9 tools
bq_describe_tableB

Get table schema, metadata, and statistics

ParametersJSON Schema
NameRequiredDescriptionDefault
table_idYesThe table ID
dataset_idYesThe dataset ID
project_idNoGCP project ID (uses default if not provided)
format_outputNoWhether to format schema as table string

TDQS

B3.3/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It correctly implies a read-only operation ('Get') and lists output categories (schema, metadata, statistics), but does not disclose permissions, latency, or data freshness. Adequate but not detailed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence that front-loads the verb and resource. Every word contributes meaning with zero waste.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple read tool with a well-documented input schema and no output schema, the description gives a high-level summary but lacks specifics on the return format, field details, or how it differs from similar siblings. It meets minimum viability.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

All 4 parameters are fully documented in the input schema (100% coverage). The description adds no extra parameter semantics beyond the schema descriptions, so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'Get' and the resource 'table schema, metadata, and statistics'. However, it does not differentiate from sibling tool 'bq_get_table_info', which likely has overlapping functionality.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives like 'bq_get_table_info' or 'bq_list_tables'. It lacks when-not-to-use or context for selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bq_dry_run_sqlB

Perform a dry-run of a BigQuery SQL query to get cost estimates and metadata

ParametersJSON Schema
NameRequiredDescriptionDefault
sqlYesThe SQL query to dry-run
paramsNoOptional query parameters (key-value pairs)
pricePerTiBNoPrice per TiB for cost estimation (defaults to env var or 5.0)

TDQS

B3.1/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description bears full responsibility for behavioral disclosure. It only states the tool performs a dry-run and returns cost estimates and metadata, but fails to mention key aspects such as idempotency (safe to call multiple times), required permissions, rate limits, or what exactly 'metadata' includes. The non-destructive nature is implied but not explicit.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence that efficiently conveys the tool's purpose. It is front-loaded and contains no unnecessary words or information, earning its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with 3 parameters (one nested object) and no output schema, the description is minimal. It outlines the goal but omits details on return values, error handling, and edge cases. While the tool is straightforward, the lack of output schema means the description should provide more context on what the agent can expect from the dry-run results.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with each parameter described in the input schema. The description itself adds no additional semantic meaning beyond what the schema provides. Baseline is 3 because the schema does the heavy lifting; the description does not compensate for any gaps.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool performs a dry-run of a BigQuery SQL query to get cost estimates and metadata. It uses a specific verb (dry-run) and resource (BigQuery SQL query). However, it does not distinguish from the sibling tool 'bq_validate_sql', which may also involve checking queries, reducing clarity on when to use each.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives like bq_validate_sql. There is no mention of prerequisites, context, or situations where this tool is appropriate or not, leaving the agent with no decision support.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bq_extract_dependenciesC

Extract table and column dependencies from BigQuery SQL

ParametersJSON Schema
NameRequiredDescriptionDefault
sqlYesThe SQL query to analyze
paramsNoOptional query parameters (key-value pairs)

TDQS

C2.9/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description must fully disclose behavioral traits. It does not mention whether the tool executes the query, is read-only, requires permissions, or has side effects. 'Extract' implies reading but it is not explicit.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single concise sentence with no redundant information. Every word is necessary.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool extracts dependencies but provides no output schema, leaving the agent uninformed about the return format. Given the complexity of dependencies (tables, columns), the description is too sparse.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already describes both parameters. The description adds no additional meaning beyond the schema, so baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses the specific verb 'Extract' and the resource 'table and column dependencies from BigQuery SQL', making the action clear. It implicitly distinguishes from siblings like bq_validate_query_syntax, but does not explicitly differentiate.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus alternatives (e.g., bq_validate_sql). The description lacks any context about appropriate use cases or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bq_get_table_infoB

Get comprehensive table information including partitioning and clustering

ParametersJSON Schema
NameRequiredDescriptionDefault
table_idYesThe table ID
dataset_idYesThe dataset ID
project_idNoGCP project ID (uses default if not provided)

TDQS

B3.1/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description must carry the full burden of behavioral transparency. It mentions the tool is a 'get' operation but does not disclose auth requirements, error handling, or whether it is read-only. The inclusion of partitioning and clustering adds some output context but not behavioral traits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence that states the tool's purpose without any wasted words. It is maximally concise while still conveying essential information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple information-retrieval tool with three parameters and no output schema, the description provides the core purpose and hints at output content (partitioning, clustering). However, it lacks details on error behavior, output format, and differentiation from siblings, making it adequate but incomplete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Input schema has 100% description coverage, so baseline is 3. The description does not add any extra meaning to the parameters beyond the schema, as it focuses on the output instead.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool retrieves comprehensive table information including partitioning and clustering. However, it does not explicitly distinguish itself from the sibling tool bq_describe_table, which likely has overlapping functionality.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives like bq_describe_table. The description lacks any usage context or prerequisites.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bq_list_datasetsB

List all datasets in the BigQuery project

ParametersJSON Schema
NameRequiredDescriptionDefault
project_idNoGCP project ID (uses default if not provided)
max_resultsNoMaximum number of datasets to return

TDQS

B3.1/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided. The description lacks behavioral details such as pagination, rate limits, or error handling. The claim 'List all datasets' is contradicted by the max_results parameter, which limits results.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Single sentence without fluff, but could be more informative about behavior. It is efficient but slightly under-specified.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema, so description should explain return format. It does not. Lacks context on when to use vs siblings like bq_list_tables. Insufficient for an agent to fully understand the tool's role.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema descriptions cover 100% of parameters with clear meanings. The description adds no extra value beyond the schema, meeting the baseline but not exceeding it.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'List' and the resource 'datasets in the BigQuery project', distinguishing it from siblings like bq_list_tables which list tables instead.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool vs alternatives (e.g., bq_list_tables for tables). Missing context on prerequisites or suitable scenarios.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bq_list_tablesA

List all tables in a BigQuery dataset with metadata

ParametersJSON Schema
NameRequiredDescriptionDefault
dataset_idYesThe dataset ID
project_idNoGCP project ID (uses default if not provided)
max_resultsNoMaximum number of tables
table_type_filterNoFilter by table types (TABLE, VIEW, EXTERNAL, MATERIALIZED_VIEW)

TDQS

A3.7/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided, so the description bears full burden. It states the operation is a listing with metadata but omits behavioral details like pagination, rate limits, or whether it requires specific permissions. It is not misleading but leaves gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Single sentence of 8 words, front-loaded with purpose. Every word earns its place; no wasted text.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Tool has no output schema. Description says 'with metadata' but does not specify what metadata fields are returned. For a list operation, this is adequate but not complete. Parameters are well-documented, but return value details are missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Input schema has 100% coverage with descriptions for all 4 parameters. The description adds no extra meaning beyond 'with metadata', which hints at return content. Baseline is 3 since schema already provides clarity.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'List all tables in a BigQuery dataset with metadata', specifying the verb 'list', resource 'tables', and scope 'in a BigQuery dataset'. It distinguishes itself from siblings like bq_describe_table and bq_get_table_info effectively.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit guidance on when to use this tool vs alternatives (e.g., bq_list_datasets lists datasets, not tables). The description implies usage for listing tables with metadata but doesn't provide when-not or exclusion criteria.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bq_preview_tableB

Get a preview of table data without running a query job (cost-free)

ParametersJSON Schema
NameRequiredDescriptionDefault
table_idYesThe table ID
dataset_idYesThe dataset ID
project_idNoGCP project ID (uses default if not provided)
max_resultsNoMaximum number of rows to preview (default: 5, hard limit: 10)

TDQS

B3.4/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are present, so the description must fully disclose behavior. It mentions cost-free and no query job, but fails to describe return format (e.g., rows), ordering (first rows?), or the hard limit of 10 from the schema. This omission leaves significant behavioral unknowns.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single, front-loaded sentence with zero wasted words. It efficiently conveys purpose and key differentiator.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema, the description should explain return values (e.g., 'returns first N rows as JSON') but does not. It also omits details like permission requirements or that preview uses the first rows. The tool is simple, but the description is incomplete for safe invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with all parameters described in the schema. The description adds no extra meaning beyond summarizing the schema. Thus baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('preview table data') and key benefit ('cost-free, without running a query job'). It distinguishes from siblings like bq_describe_table (schema) and bq_run_query (costly query). This provides a specific verb+resource with differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies use for quick, cost-free previews but lacks explicit when-not or alternative tools. With siblings including bq_get_table_info and bq_dry_run_sql, no comparison or exclusion is provided, leaving guidance implicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bq_validate_query_syntaxC

Enhanced syntax validation with detailed error reporting

ParametersJSON Schema
NameRequiredDescriptionDefault
sqlYesThe SQL query to validate
paramsNoOptional query parameters (key-value pairs)

TDQS

C2.5/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided, so description carries full burden. It claims 'detailed error reporting' but does not explain what constitutes enhanced behavior, side effects, or limitations. Lacks any behavioral context beyond a vague promise.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness3/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is very short (one phrase), but it is front-loaded with functionality. However, it sacrifices necessary detail for brevity, making it less helpful.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with no output schema and two parameters, the description should explain what 'enhanced' validation entails, expected error messages, or usage examples. It fails to provide sufficient context for effective use.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with adequate parameter descriptions. The tool description adds no additional parameter-specific meaning, achieving only baseline value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose3/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states 'syntax validation' which implies validating SQL syntax, but does not explicitly mention SQL queries. The phrase 'enhanced...with detailed error reporting' adds some clarity but fails to distinguish from sibling tool 'bq_validate_sql'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus the similar sibling 'bq_validate_sql'. The description offers no context for selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

bq_validate_sqlA

Validate BigQuery SQL syntax without executing the query

ParametersJSON Schema
NameRequiredDescriptionDefault
sqlYesThe SQL query to validate
paramsNoOptional query parameters (key-value pairs)

TDQS

A3.7/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, and the description only states the tool validates without executing. It does not disclose what happens on invalid syntax, auth requirements, or whether it checks table existence, leaving significant behavioral gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single 8-word sentence with no extraneous information, achieving maximum conciseness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity (2 parameters, no output schema, no annotations), the description is minimally adequate but lacks details about return values or behavior on errors, which would help agents understand the output.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%; both parameters have clear descriptions in the schema. The tool description adds no extra parameter information beyond what the schema already provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description specifies the verb 'validate' and the resource 'BigQuery SQL syntax', and clearly states it does not execute the query, distinguishing it from bq_dry_run_sql which executes a dry run.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies use for syntax checking only, not execution. It contrasts with 'without executing', but does not explicitly name when not to use or mention bq_dry_run_sql as an alternative.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

  1. 1 tool updatev0.7.0
    • Addedbq_preview_table
  2. 4 tool updatesv0.2.1
    • Removedbq_analyze_query_performance
    • Removedbq_analyze_query_structure
    • Changedbq_list_tables1 field changed
      • changedInput schema / properties / max_results / description
        Previous value: -"Maximum number of tables to return"New value: +"Maximum number of tables"
    • Removedbq_query_info_schema
  3. 9 tool updatesv1.0.0
    • Addedbq_analyze_query_performance
    • Addedbq_analyze_query_structure
    • Addedbq_describe_table
    • Addedbq_extract_dependencies
    • Addedbq_get_table_info
    • Addedbq_list_datasets
    • Addedbq_list_tables
    • Addedbq_query_info_schema
    • Addedbq_validate_query_syntax
  4. 2 tool updates
    • First observedbq_dry_run_sql
    • First observedbq_validate_sql

TDQS

B3.1/5.0

Scored across 9 tools

Disambiguation2/5

Several tools have overlapping purposes: bq_validate_sql and bq_validate_query_syntax both validate syntax, while bq_describe_table and bq_get_table_info both return table metadata. Agents could easily confuse these and pick the wrong tool.

Naming Consistency4/5

Naming is mostly consistent with a clear bq_ prefix and snake_case verb_noun pattern. The main inconsistency is validate_sql versus validate_query_syntax, which are different names for the same kind of operation.

Tool Count4/5

Nine tools is a reasonable count for a BigQuery exploration and validation server, but at least two pairs are redundant. Trimming the duplicates would make the set tighter without losing any real capability.

Completeness4/5

The server covers dataset/table discovery, schemas, partitioning/clustering metadata, data previews, SQL syntax validation, dry-run cost estimation, and dependency extraction. Minor gaps exist, such as no way to list columns independently or execute queries, but these are outside the validator scope.

Maintenance

ActivitySlowing
ResponsivenessNo issues

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