Hythe

Name: Hythe
Author: hythe-dev

by hythe-devversion 0.2.0i★ –iRuns on your computer

Registry namedev.hythe/hythe

Install

Overview

Description from the maker (original English)

HYTHE — coordination bus + shared truth for AI agent fleets — self-hosted MCP server + stdio bridge.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other
You need to fill in: HYTHE_AGENT_ID, API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: HYTHE_AGENT_ID, HYTHE_AGENT_KEY_FILE, HYTHE_AGENT_AUTH_MODE, API_KEY, MCP_HOST, MCP_PORT

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "hythe": {
      "command": "npx",
      "args": [
        "-y",
        "@hythe/mcp"
      ],
      "env": {
        "HYTHE_AGENT_ID": "your-value",
        "HYTHE_AGENT_KEY_FILE": "your-value",
        "HYTHE_AGENT_AUTH_MODE": "your-value",
        "API_KEY": "your-value",
        "MCP_HOST": "your-value",
        "MCP_PORT": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add hythe --env HYTHE_AGENT_ID=your-value --env HYTHE_AGENT_KEY_FILE=your-value --env HYTHE_AGENT_AUTH_MODE=your-value --env API_KEY=your-value --env MCP_HOST=your-value --env MCP_PORT=your-value -- npx -y @hythe/mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "hythe": {
      "command": "npx",
      "args": [
        "-y",
        "@hythe/mcp"
      ],
      "env": {
        "HYTHE_AGENT_ID": "your-value",
        "HYTHE_AGENT_KEY_FILE": "your-value",
        "HYTHE_AGENT_AUTH_MODE": "your-value",
        "API_KEY": "your-value",
        "MCP_HOST": "your-value",
        "MCP_PORT": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "hythe": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@hythe/mcp"
      ],
      "env": {
        "HYTHE_AGENT_ID": "your-value",
        "HYTHE_AGENT_KEY_FILE": "your-value",
        "HYTHE_AGENT_AUTH_MODE": "your-value",
        "API_KEY": "your-value",
        "MCP_HOST": "your-value",
        "MCP_PORT": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

HYTHE_AGENT_ID required env
Stable exact agent identity for this client lane; required so restarts and compaction cannot adopt another principal
HYTHE_AGENT_KEY_FILE env
Optional path to one protected per-agent credential file: regular, non-symlink, owned by the client user, mode 0400 or 0600, containing one hya1 token. Never place the token itself in an environment…
HYTHE_AGENT_AUTH_MODE env
Client authorization expectation: observe, mixed, or required (default observe). Move to mixed and then required only after this exact lane has a credential and passes /agent/whoami.
API_KEY secret required env
Shared API key authenticating the bridge to your self-hosted HYTHE server (create a protected .env with: npx -y @hythe/mcp@0.2.0 init --write-env --agent-id )
MCP_HOST env
HYTHE server host (default 127.0.0.1)
MCP_PORT env
HYTHE server port (default 6174)

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

✓ Pass
Maker matches the repo
The registry name was verified against the domain hythe.dev (the registry checks domain ownership)
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 32435 servers in this category
Published to the registry more recently than 33% of the other 32435 servers in this category
Basic checks equal to or better than 100% of the other 32435 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Hythe safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: HYTHE_AGENT_ID, API_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.2.0) reached the registry 2 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, Apify MCP Server

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

HYTHE

A coordination bus + shared truth for your agent fleet. Self-hosted, two-component setup: a dockerized server plus a thin stdio bridge for your MCP clients.

HYTHE is an MCP server that lets multiple AI coding agents — Claude Code, Codex, Cursor, custom harnesses — share state, preserve context across sessions, and coordinate with each other. It is not another memory store. Its differentiators:

Supersession + current-state resolution: observations supersede each other (replace-current), and get_current_observation resolves the chain server-side — so readers get the newest non-superseded state. Conflict handling is implemented: checkpoint is branch-preserving CAS — concurrent writers branch rather than overwrite, and conflicts surface as heads, never silently resolved (contract-tested; see the evidence ledger).
Agent messaging with a tracked delivery lifecycle: direct and capability-based sends, message supersession, read-state as a shared signal, atomic ack+archive. (Described as *tracked lifecycle*, not guaranteed delivery — the states are honest about what the server knows.)
The Adaptive Coordination Protocol (ACP): the ETA-driven coordination discipline that co-evolved with the server — published as docs/SPEC.md with a real two-harness worked tutorial.

Documentation

Doc	What it covers
Quickstart	Clean machine → two coordinating agents in ~15 minutes
Concepts	One current truth, messaging lifecycle, resume/checkpoint, honest security model
Checkpoint / resume v3	Current-head pointer, reconciliation, record / patch, the v3 read model, and the one-time adoption step for scopes written before v3
ACP SPEC	The coordination protocol, versioned (1.0.0)
Tutorial	Annotated transcript of a real Claude Code ↔ Codex review loop from the original Engram deployment
Tool compatibility map	The 20-tool v1 surface; every retired tool and its exact replacement
Backup & restore	Tested SQLite backup/restore/compaction runbook
Agent credential operator	Offline issuance, attestation, promotion, rotation, and revocation
Private-residue adjudication	Hash-bound, owner-approved disposition of ambiguous historical rows
SQLite physical sanitation	Verified offline VACUUM and no-clobber promotion after logical cleanup
Pavilion production	Pinned deployment, readiness, shutdown, canary, and rollback contract

Status

Version 0.2.0. This source tree and package define the reviewed 0.2.0 release. Version 0.2.0 preserves 0.1.7's dual-proof agent authorization, exact-mailbox/private-payload containment, bounded related-context discovery, latency-SLO recovery and the offline adjudicator, and adds checkpoint / resume resultVersion: 3: an explicit current-head pointer per scope, a reconcile operation that folds live heads into one survivor and resolves divergent values causally, append-only verified fact/loop versions, a read model that only promotes values proven on the accepted lineage, and record / patch operations on the pointed head. Every v1 / v2 request and result shape is frozen; v3 is opt-in per call, so a 0.1.7 client keeps working against a 0.2.0 server. The dependency tree moved to Express 5, clearing two moderate qs advisories. This release runs on the reference production host since 2026-09-05. All 0.2.0 rollout configurations pin @hythe/mcp@0.2.0; verify that the registry returns that exact version before production use. The predecessor @tomcat65/engram-mcp and io.github.tomcat65/engram remain available as compatibility history and are never unpublished. See CHANGELOG.md and the v3 guide.

House rule: every claim in these docs must trace to a test or a measurement (see the evidence ledger below). Claims that don't are bugs.

Evidence ledger

Claim	Evidence	Source	Date
Tree green, full gates	Source and clean installed-package gates cover 49 Vitest files (530 passed, 2 skipped, 6 explicit todos), 107 migration checks, 43 release-tree checks, 31 agent-kit checks, zero production npm audit findings, registry validation, and an isolated Docker start/readiness/MCP/WebSocket/graceful-shutdown canary.	`.github/workflows/ci.yml`, `tests/`, `src/migrations/`, `clients/agent-kit/tests/test-setup.sh`, `scripts/verify-hythe-release-tree.test.mjs`, `scripts/verify-packed-consumer.mjs`	2026-08-14
Compaction identity fails closed	Startup and post-compaction hooks reject missing, conflicting, or invalid identity; the bridge binds acting tools and message-resource recipients to the configured exact lane before any HTTP request.	`clients/agent-kit/tests/test-setup.sh`, `tests/contract-bridge-identity.test.ts`	2026-08-13
Exact mailboxes stay isolated	Houston/Hythe, case variants, display metadata, legacy identity history, cross-tenant poisoning, suffix handles, lifecycle changes, supersession, HTTP, and ENG-4 authorship have negative isolation coverage.	`tests/contract-message-identity-isolation.test.ts`, `tests/contract-eng4-p0.test.ts`	2026-08-13
Private message bodies stay out of shared graph surfaces	Historical, oversized, malformed, alias-linked, relation-linked, imported, exported, searched, graphed, logged, and restored payload paths are covered; hidden children do not leak through counts.	`tests/contract-message-payload-isolation.test.ts`, `tests/contract-data-payload-isolation.test.ts`, `tests/contract-log-confidentiality.test.ts`	2026-08-13
Cleanup is offline and fail-closed	Migration 007, owner-approved adjudication, and physical sanitation are dry-run/plan-first, bind execution to reviewed database and decision evidence, require verified no-clobber artifacts, refuse unresolved custody, and preserve rollback state.	`src/migrations/007-private-message-residue.mjs`, `src/migrations/private-message-residue-adjudication.mjs`, `src/migrations/vacuum-sanitized-database.mjs`, `docs/`	2026-08-14
Per-agent authority is server-derived	The base key proves deployment/tenant access; a separate protected-file `hya1` credential proves the exact agent. Required mode rejects stripped proof, mismatched identity, insufficient scope, revoked credentials, and stale WebSocket sessions.	`src/agent-auth/`, `tests/contract-agent-auth-foundation.test.ts`, `tests/contract-agent-auth-server.test.ts`, `tests/contract-agent-key-client.test.ts`	2026-08-14
Install and discovery surfaces agree	CLI and registry surfaces require an exact lane identity and expose only a protected per-agent key-file path plus an explicit authorization mode; tools and resource templates served through HTTP match the stdio bridge path.	`tests/contract-cli.test.ts`, `tests/contract-agent-key-client.test.ts`, `tests/contract-mcp-resources-http.test.ts`, `scripts/verify-hythe-release-tree.test.mjs`	2026-08-14
Current head is explicit, never guessed	The pointer advances only from the pointed head; stale parents branch without becoming current; a pointer at a non-live snapshot fails closed; snapshot rows are immutable by trigger. 33 contract tests.	`tests/contract-eng4-h1-head-pointer.test.ts`	2026-09-03
Versions and coverage are exact and verified	Every ledger tuple gets exactly one disposition; the startup backfill is all-or-nothing and idempotent; a bidirectional parity verifier fails closed on any missing, extra or mismatched row. 32 contract tests.	`tests/contract-eng4-h2-version-foundation.test.ts`	2026-09-03
Reconciliation is CAS-bound and causal	Exact live-head set and pointer are compare-and-set; every non-survivor head is retired (never deleted); divergent values resolve only by bound accept, reject or lineage reject; the record is payload-bound and re-verified on replay and read. 34 contract tests.	`tests/contract-eng4-h3-reconcile.test.ts`	2026-09-04
The v3 read model promotes only proven values	`currentFacts` / `openLoops` come only from verified versions on the accepted lineage with provenance; everything else is accounted as divergent or legacy with closed coverage. 29 contract tests.	`tests/contract-eng4-h4-read-model.test.ts`	2026-09-04
record / patch cannot promote stale state	Only the pointed head is admitted (conflict otherwise); state is materialized from the hash-verified payload; each payload is read once per call; snapshot resources serve exactly the verified bytes. 21 contract tests, four review rounds.	`tests/contract-eng4-h5-record-patch.test.ts`	2026-09-04
Express 5 keeps the HTTP contract	A bodiless or wrong-content-type request is handled like an empty JSON body on every parsed route, never a framework 500; production audit reports zero findings.	`tests/contract-express5-body-contract.test.ts`, `.github/workflows/ci.yml` run 33878587010	2026-09-04
Production migration verified on a copy first	The v3 schema and backfill were exercised against a copy of the production database on the production host before cutover; the live cutover took 17 s with row counts identical to the verified cold backup.	`docs/PAVILION-PRODUCTION.md`; operator log `engram-prod/releases/hythe-74a324c-cutover-20260905T005551Z.log` on the host	2026-09-05

v1 surface (short)

Install (two-component setup): server via docker compose up, then the @hythe/mcp stdio bridge per MCP client; first-run wizard stores the API key in a protected .env and prints secret-free file-referencing config for Claude Code / Codex / Cursor / Claude Desktop; optional namespaced (demo-*) demo seed on an otherwise empty DB.
Knowledge graph: entities, observations, relations, supersession, current-state resolution, conflict surfacing.
Related-context discovery: exact scope anchoring plus automatic bounded vector retrieval and graph-path reranking, with currentness/evidence/provenance explanations and no implicit writes.
Agent messaging: direct, capability-based, superseding; tracked delivery lifecycle.
`resume` / `checkpoint`: budgeted one-call session rehydration with closed coverage accounting, and CAS-protected, branch-preserving structured state capture. With resultVersion: 3: an explicit current-head pointer, reconcile to fold heads and resolve divergent values, verified fact/loop versions with provenance, and record / patch on the pointed head — see the v3 guide.
ACP: the coordination protocol as a versioned spec + real worked example.

Embedding runtime contract

The published npm package does not install a transformer engine by default. Without one, HYTHE still provides deterministic 384-dimension token-hash vectors plus lexical ranking; it does not download a model or create a model cache. @xenova/transformers@2.17.2 is an optional peer for operators who deliberately provide it from their own audited dependency root.

The Docker image keeps semantic behavior stable through a separate, locked /opt/hythe-transformers runtime. Its startup preflight loads the configured Xenova/all-MiniLM-L6-v2 q8 model and requires one finite 384-dimension embedding before the server starts. When SQLITE_VEC_ALLOW_REMOTE_MODELS=false, the configured SQLITE_VEC_CACHE_DIR must already contain that model. Do not switch between transformer and hash embeddings on a populated vector index: retain the same provider/model/dimensions or rebuild the vector index first.

License

Apache-2.0

Hythe

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Apify MCP Server

README from the maker

HYTHE

Documentation

Status

Evidence ledger

v1 surface (short)

Embedding runtime contract

License