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shadow-dba

mssql-dba-mcp

by shadow-dba

Get Current Blocking and Locking

mssql_blocking
Read-onlyIdempotent

Detect SQL Server blocking by listing blocked sessions, blocking sessions, wait types, wait times, and queries. Empty result means no blocking.

Instructions

Blocking and locking now: blocked sessions with the blocking session, wait type, wait time and query text. An empty result means no blocking.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A3.9/5.0
Behavior4/5

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuine value beyond that: the exact output fields and the semantics of an empty result, which an agent needs in order to report findings correctly.

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?

Two tight sentences with no filler; the core purpose is front-loaded and the empty-result caveat follows immediately. Every clause carries information.

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

Completeness4/5

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

With no output schema, the description carries the return-shape burden and does so by listing the key fields and the empty-result case. It omits only minor operational context such as the required permission (VIEW SERVER STATE) and whether results are instance-wide or per-database.

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

Parameters4/5

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

The tool takes zero parameters, so the baseline is 4. The description correctly implies no inputs are required, and there is nothing parameter-related left unexplained.

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 names the resource (blocking/locking) and enumerates exactly what the tool returns: blocked sessions, blocking session, wait type, wait time, and query text. This is far more specific than the sibling names alone, though it never explicitly distinguishes itself from adjacent diagnostics like mssql_running_requests or mssql_wait_stats.

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?

Usage is implied — this is clearly the tool for diagnosing current blocking — and the 'empty result means no blocking' line tells the agent how to interpret the outcome. However, there is no explicit when-to-use guidance and no mention of alternatives such as mssql_wait_stats for historical wait analysis.

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