Reference

parseltongue-mcp

A local messaging system built on Elder Pliny’s P4RS3LT0NGV3 transform catalog that keeps three ideas separate: appearance, confidentiality, and an MCP boundary that never receives plaintext secrets.

Who it is for — and why

Builders studying how an MCP tool can expose useful inspection and concealment features without pulling plaintext secrets into model context.

Proof you can inspect

The 222-transform bridge explicitly credits and links Elder Pliny’s upstream P4RS3LT0NGV3 project; the separate capsule layer, MCP boundary, and tests are this repository’s additions
The repository passes 104 tests plus license-seam, license-consistency, and no-secret guards
The capsule layer uses X25519, XChaCha20-Poly1305, Ed25519, and Argon2id, while five transform tools and seven capsule tools remain unable to seal or open a private message
The tool output states that concealment adds no confidentiality, preventing the interface from turning representation into a security claim

Limits

There is no tagged release, and the transform server needs the upstream project as a separate checkout
Shared-code concealment hides that a message exists but does not authenticate the sender; identity capsules authenticate the sender but visibly look like capsules
The servers are local-first by design; hosting them would move key derivation and plaintext onto the operator's machine and invalidate the security boundary

ELI5 · three different jobs

Changing how a message looks is not the same as locking it.

1 · Transform

Change the costume

Base64, styled Unicode, and zero-width text can make the same information look different. Anyone who recognizes the costume can reverse it. No secrecy.

2 · Encrypt

Lock the message

The capsule layer turns plaintext into ciphertext for a recipient. The key—not the visual trick—is what provides confidentiality.

3 · Conceal

Hide the locked box

A sealed note can ride inside ordinary-looking cover text. The unlock code travels a different route, or the whole design collapses.

Harmless example generator

See the message journey without creating a real secret.

This browser demo performs a reversible Base64 transform and draws the secure workflow. It does not encrypt or conceal your text; use the audited local CLI for that.

MessageOrdinary cover text

Transform only · reversible

Looks different. Still not encrypted.

Real secure path · local CLIplaintext → sealed capsule → conceal in cover

Code · separate route

Send this somewhere else—not beside the cover message.

Recipient opens locally

The MCP server never receives the passphrase or recovered plaintext.

Lineage & credit

The transform catalog starts with Elder Pliny.

Explicit attribution: the 222-transform bridge is built onElder Pliny’s P4RS3LT0NGV3 project. This repository makes that catalog agent-callable and adds a separately licensed local capsule layer, security boundary, tests, and offline explainer. It does not claim the upstream transform work as original.

Quick start

git clone https://github.com/0xreconlion/parseltongue-mcp.git && cd parseltongue-mcp && git clone https://github.com/elder-plinius/P4RS3LT0NGV3 vendor/P4RS3LT0NGV3 && npm install && npm test

Source-to-build: this project does not claim a packaged release. Its repository documents the required dependencies and the failure mode when one is missing.

Access and evidence

Repository Documentation →Related evidence →