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APEX PSI

Official registry Security

Append-only evidence receipts for AI records: seal, verify, cite, chain-check, anchor status.

Source code Documentation

What can you do with APEX PSI?

  • It does not store your content. Only the hash leaves your machine.
  • It does not certify, grade, score or approve anything.
  • It exposes no edit or delete path: the interface this server uses is write-once sealing plus
  • It is not a legal opinion, and no court has agreed to accept a receipt in advance.

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package apex-psi-mcp
Claude Code 
claude mcp add apex-psi -e 'APEX_API_BASE=<APEX_API_BASE>' -e 'APEX_API_KEY=<your apex_api_key>' -- npx -y apex-psi-mcp@1.1.2
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "apex-psi": {
            "command": "npx",
            "args": [
                "-y",
                "apex-psi-mcp@1.1.2"
            ],
            "env": {
                "APEX_API_BASE": "<APEX_API_BASE>",
                "APEX_API_KEY": "<your apex_api_key>"
            }
        }
    }
}

Environment variables

  • APEX_API_BASE Optional API base URL override. Default: https://qhtntebpcribjiwrdtdd.supabase.co/functions/v1 (the public APEX PSI notary). Free allowance with no key: 20 operations/minute, 100/day.
  • APEX_API_KEY secret Optional API key. It raises the daily ceiling for a workload; it is never required to seal or to verify, and it cannot change what a receipt is allowed to claim.

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. APEX PSI MCP server
  2. Tools
  3. Install
  4. Prove it works in two minutes
  5. Limits, stated plainly
  6. Configuration
  7. What this server does not do
  8. Links
  9. License

APEX PSI MCP server

Apex PSI is not a tool and not a product. It is the verification substrate — the layer beneath proof. It does not judge. It does not certify. It only remembers. This server is one application built on that layer.

One config line gives any MCP-capable agent (Claude, Cursor, Qoder, Cline, Windsurf, and the rest) five evidence tools: seal, verify, anchor, cite, verify_chain.

A seal records the SHA-256 hash of a decision, document or artefact in a public append-only ledger and returns a receipt. Anyone can look that hash up again — free, forever, with no account, no key and no cooperation from us.

What a receipt proves: that this exact content existed at this timestamp, and has not changed since. What it never proves: that the content is true. A seal is an audit trail, not a verdict.

Tools

ToolWhat it actually does
sealWrites the record's SHA-256 hash to the ledger and returns a receipt carrying an Ed25519 signature over the Merkle leaf, an ML-DSA-65 post-quantum signature, and — when a slot is available — an LMS-W4-SHA256 signature. The receipt's own algorithm field states which of those it got.
verifyLooks a hash (or a whole receipt) up in the ledger and reports whether it is present and unchanged. Integrity, not truth.
anchorReads the Bitcoin/OpenTimestamps anchoring state of the ledger's pending Merkle roots. Pass action: "anchor" explicitly to request that pending roots be submitted — an anchor is confirmed only when a real block is found.
citeTurns a receipt into a citation (APA, BibTeX, MLA) that points at a public, independently checkable record.
verify_chainRecomputes each hash's presence and Merkle continuity across a chain of receipts. A recomputation result, not an opinion.

Install

Add to your MCP client config:

{
  "mcpServers": {
    "apex-psi": {
      "command": "npx",
      "args": ["-y", "apex-psi-mcp"]
    }
  }
}

Or locally: npm install apex-psi-mcp.

Prove it works in two minutes

  1. Ask the agent: "Seal the sentence 'hello psi' with APEX PSI."
  2. Take the decision_hash from the receipt and paste it into the public verifier: https://www.ai-governance-standard.com/verify

If the site returns the record, the seal is real. You never had to trust this server, our npm package, or our word — which is the entire point of the protocol.

Limits, stated plainly

Free use needs no account and no key: 20 operations per minute and 100 per day, enforced per server instance — a flood guard rather than a subscription quota. Above that, an API key raises the ceiling; capacity is priced, the finding never is. Verification itself is unlimited and free: running the verifier locally costs nothing at all — apex-psi-verifier on npm, psi-verifier on PyPI.

Configuration

Environment variables (both optional):

  • APEX_API_BASE — override the notary endpoint. Default: https://qhtntebpcribjiwrdtdd.supabase.co/functions/v1
  • APEX_API_KEY — raises the daily ceiling for a workload. Never required to seal or verify.

What this server does not do

  • It does not store your content. Only the hash leaves your machine.
  • It does not certify, grade, score or approve anything.
  • It exposes no edit or delete path: the interface this server uses is write-once sealing plus read-only lookup. The check that matters is yours to run — re-verify any receipt at any time, and any change shows up as a failed lookup.
  • It is not a legal opinion, and no court has agreed to accept a receipt in advance.

License

MIT

Frequently asked questions

What is APEX PSI?

Append-only evidence receipts for AI records: seal, verify, cite, chain-check, anchor status.

How do I install APEX PSI?

It runs on your machine. In Claude Code: claude mcp add apex-psi -e 'APEX_API_BASE=<APEX_API_BASE>' -e 'APEX_API_KEY=<your apex_api_key>' -- npx -y apex-psi-mcp@1.1.2. For other clients, paste the JSON configuration from this page into their MCP settings.

Does APEX PSI need an API key?

Yes. It expects APEX_API_KEY, which you set in its configuration.

Is APEX PSI open source?

Its code is public on GitHub, but the repository does not declare a standard license.

Who maintains APEX PSI?

It is published by kawal393. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.