Marketplace epistemic-checkpoint
install
source · Clone the upstream repo
git clone https://github.com/aiskillstore/marketplace
Claude Code · Install into ~/.claude/skills/
T=$(mktemp -d) && git clone --depth=1 https://github.com/aiskillstore/marketplace "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/ancplua/epistemic-checkpoint" ~/.claude/skills/aiskillstore-marketplace-epistemic-checkpoint && rm -rf "$T"
manifest:
skills/ancplua/epistemic-checkpoint/SKILL.mdsource content
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."
WRONG:
"React 19 is still in beta, so..."
CORRECT:
"Checking React 19 status... [WebSearch] ... React 19 was released December 2024 as stable. Proceeding with React 19 stable patterns."
Common Danger Patterns
| Topic | Danger Pattern | Likely Truth |
|---|---|---|
| .NET | "preview", "not released" | .NET 10 LTS since Nov 2025 |
| React | "beta", "experimental" | React 19 stable since Dec 2024 |
| Node | "current" without version | Always specify exact version |
| Python | "3.x is latest" | Verify - 3.13+ exists |
Output Format
When this skill activates, structure your verification as:
Epistemic Checkpoint Claim to verify: [what you were about to assume] Source checked: [assertions.yaml / WebSearch / official docs] Verified fact: [the actual truth] Confidence: [high/medium/low] Proceeding with verified baseline...