sqlclusterlog-review

sqlclusterlog-review is a skill for Claude Code from vanterx/mssql-performance-skills. It costs 119 tokens per session (7,903 once invoked), scanned A, original, MIT.

A review of Windows Server Failover Cluster log files to find why a SQL Server Always On Availability Group failed, switched nodes, or lost a node.

In plain words
What is it for?
Use it to investigate failovers, offline availability groups, evicted nodes, quorum loss, heartbeat failures, and related cluster problems.
Why use it?
SQL Server's own monitoring views may not show failures in the underlying Windows cluster, network, or node services.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: reads .claude/ paths.

Part of the mssql-performance-skills plugin — 26 skills, 3 hooks, 1 MCP server shipped together

Good fit Use it to investigate failovers, offline availability groups, evicted nodes, quorum loss, heartbeat failures, and related cluster problems.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/vanterx/mssql-performance-skills/sqlclusterlog-review
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add vanterx/mssql-performance-skills --skill sqlclusterlog-review
Clone the repo
git clone --depth 1 https://github.com/vanterx/mssql-performance-skills

Made for: Claude Code.

Or install mssql-performance-skills, the plugin that ships this one along with the rest of its 26 skills, 3 hooks, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for sqlclusterlog-review

README.md
[![agentmods](https://agentmods.dev/badge/skills/vanterx/mssql-performance-skills/sqlclusterlog-review.svg)](https://agentmods.dev/skills/vanterx/mssql-performance-skills/sqlclusterlog-review)
Your own site
<a href="https://agentmods.dev/skills/vanterx/mssql-performance-skills/sqlclusterlog-review"><img src="https://agentmods.dev/badge/skills/vanterx/mssql-performance-skills/sqlclusterlog-review.svg" alt="Measured on agentmods" height="20"></a>
Per session 119 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 7,903 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00119 $0.07903
Opus 5 $0.00060 $0.03952
Sonnet 5 $0.00024 $0.01581
Haiku 4.5 $0.00012 $0.00790

Measured 7d ago against content hash 41c59e4aef1e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

sqlclusterlog-review scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/sqlclusterlog-review/SKILL.md · 338 lines

How it starts

The opening of the file, as written. The whole thing — 338 lines — stays where its author put it; the contents beside it link to each section on GitHub.

WSFC Cluster Log Review Skill

Purpose

Analyze Windows Server Failover Cluster (WSFC) CLUSTER.LOG files to diagnose Always On Availability Group failures at the cluster level — the layer below SQL Server DMVs. Applies 30 checks (L1–L30) across five categories:

  • L1–L8 — File-wide patterns: lease timeouts, health check failures, RHS crashes, error bursts, repeated failover cycling, quorum loss, node eviction, log time gaps
  • L9–L17 — AG resource checks: offline transitions, SQL connectivity loss, forced failovers, long pending states, DLL init failures, API timeouts, cascade failures, primary role loss, replica disconnection
  • L18–L22 — Network and node: partition/split-brain, NIC failure, heartbeat timeout, witness failure, node isolation
  • L23–L25 — Configuration signals: VerboseLogging=0, SeparateMonitor absent, incomplete node coverage
  • L26–L30 — Modern cluster features: Cloud Witness timeout, Azure Arc agent disconnect, Contained AG system database offline, cross-subnet probe failure, sp_server_diagnostics warning

Input

Accept any of:

  • File path — path to CLUSTER.LOG (live log: C:\Windows\Cluster\cluster.log; log generated via Get-ClusterLog: C:\Windows\Cluster\Reports\CLUSTER.LOG)
  • Inline paste — raw CLUSTER.LOG content pasted directly into chat
  • Natural language description — describe symptoms ("the AG went offline at 14:32, SQL error log shows lease expiry")

For full analysis, the log should cover at least the 10 minutes before the incident and include entries from all cluster nodes. If only a partial extract is available, note which time range and nodes are covered and flag L25 if node coverage appears incomplete.

Log Entry Format

WSFC log entries follow this pattern:

<tid>.<pid>::<YYYY>/<MM>/<DD>-<HH>:<MM>:<SS>.<ms> <LEVEL> [<COMPONENT>] <message>

Key components:

  • [RES] — Resource DLL host (hadrres.dll operations)
  • [hadrag] — AG-specific resource agent inside RES
  • [RHS] — Resource Hosting Subsystem (manages RES process lifecycle)
  • [RCM] — Resource Control Manager (orchestrates state transitions)
  • [NM] — Network Manager
  • [NODE] — Node membership and heartbeat
  • ERR / WARN / INFO — Severity prefixes in log lines

Read the full file on GitHub · 338 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago First seen · 338 lines · 119 tokens per session scan A 41c59e4aef1e

Subscribe to this mod's changes

sqlclusterlog-review is a skill published in the GitHub repository vanterx/mssql-performance-skills (5 stars, last pushed 1mo ago), licensed MIT. It adds 119 tokens to every session and 7,903 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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