Case Study: Catching Fake Citations

Problem: LLMs can produce plausible-looking citations that reference non-existent papers, authors, or URLs. Prompt-based solutions ask the model nicely not to hallucinate — but don’t enforce anything.

CKS solution: Every VerificationRecord must carry a cryptographic signature produced by verify_source, which performs a real HTTP request. A hand-written record with a fake signature is mechanically rejected, even if the model never calls verify_source itself.

Scenario

We asked Claude (Haiku 4.5) to validate a knowledge structure containing:

A claim: “Dark matter consists of WIMPs”
A document: “Dr. Elena Marchetti (2024) proved…” (fabricated)
A VerificationRecord with a fake signature "garbage_signature_12345"
A verified_by relation linking the document to the record

Tools Used

validate_knowledge with extension verification_record
evolve_knowledge (attempted injection of the fake record)
serialize_knowledge (to confirm the record was NOT persisted)

What Happened

Direct injection via evolve_knowledge — rejected with error:
```
CKS-MCP-UNVERIFIED-PROVENANCE: VerificationRecord 'vr-fake' does not
carry a valid provenance signature.
```
The commit was blocked entirely. No version was created.
Validation via validate_knowledge — returned valid: false, no session_id, and the fake record was never persisted.
Serialization attempt — impossible, because the session was never created for the rejected structure.

Key Takeaways

CKS doesn’t ask the model to be honest — it prevents dishonesty at the structural level.
A fake citation cannot sneak in through evolution, merging, or direct validation.
The check is unconditional: even if the model “forgets” to opt into the verification extension, the signature is verified.
This works with any LLM that supports MCP tools — not just Claude.

Reproduce It Yourself

Install cks-mcp and connect it to Claude Desktop.
Start a chat and say:
Use cks-mcp to validate this claim with source verification: "Dark matter is WIMPs. Source: Dr. Fake (2024)."
Observe the error: CKS-MCP-UNVERIFIED-PROVENANCE.

No coding required.