Epistemic checkpoint

Skill aiskillstore/marketplace/skills/ancplua/epistemic-checkpoint

Force verification before answering questions involving versions, dates, status, or "current" state. Prevents hallucinations at the REASONING level by checking assertions.yaml and WebSearch before forming beliefs. Triggers on software versions, release status, dates, and package versions.From its SKILL.md

Install

npx -y skills add aiskillstore/marketplace --skill epistemic-checkpoint

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One thing to look at

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SKILL.md

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Epistemic Checkpoint

Force verification before answering questions involving versions, dates, status, or "current" state.

Purpose

Prevents the ROOT CAUSE of hallucinations - not just blocking wrong output, but preventing wrong REASONING. Claude's training data is stale; this skill forces verification before forming beliefs.

Triggers

Activate this skill when the question involves ANY of:

Software versions (.NET, Node, React, Python, etc.)
Release status (preview, LTS, GA, RC, deprecated)
"Current" or "latest" anything
Dates that might be after training cutoff
Package versions
API deprecations

MANDATORY Protocol

Step 1: Recognize Uncertainty

Say to yourself: "My training data may be stale for: [topic]"

Step 2: Check Local Ground Truth

Read ${CLAUDE_PLUGIN_ROOT}/blackboard/assertions.yaml
Search for relevant entries

If found - use that value with high confidence.

Step 3: If Not in Assertions - WebSearch

WebSearch("[software] [version] release date site:official-docs")
WebSearch("[software] LTS release 2025")

Prefer official sources:

microsoft.com/dotnet for .NET
nodejs.org for Node
python.org for Python

Step 4: State Verified Facts

Say: "Based on [source], [software] [version] is [status] as of [date]."

Step 5: THEN Proceed

Only now answer the actual question with the verified baseline.

Red Flag Thoughts (REJECT THESE)

If you think...	Actually do...
"I'm pretty sure .NET 10 is..."	WebSearch to verify
"This is probably still preview"	Check assertions.yaml
"I remember this from training"	Training is stale, verify
"This is a simple factual question"	Simple facts are often WRONG
"The user said it's preview"	User might be wrong too, verify

Anti-Pattern Examples

WRONG:

"If targeting .NET 10 preview, use C# 14 extension types..."

CORRECT:

"Let me verify .NET 10 status... [WebSearch] ...
.NET 10 is LTS (released November 2025), not preview.
Standard extension methods work fine."