Deprecated. Deprecated by the publisher: Moved to dev.hythe/hythe. Install @hythe/mcp and see https://github.com/hythe-dev/hythe.
Engram
Coordination bus + shared truth for AI agent fleets — self-hosted MCP server + stdio bridge.
Runs on your machine from its package; the steps are below.
What it does
- Reads
- Writes
- High impact
Not assessed yet.
What it costs
FreeOdel charges nothing per call. The publisher may charge for its own service.
Runs locally over stdio
This server isn't hosted — your MCP client launches it from a package registry. Use one of the commands below, or drop the config into your client (e.g. Claude Desktop).
Run
npx -y @tomcat65/engram-mcp
MCP client config
{
"mcpServers": {
"engram": {
"command": "npx",
"args": [
"-y",
"@tomcat65/engram-mcp"
]
}
}
}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.
Engram 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replace-current), andget_current_observationresolves the chain server-side — so readers get the newest non-superseded state. Conflict handling is implemented:checkpointis 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 |
| ACP SPEC | The coordination protocol, versioned (1.0.0) |
| Tutorial | Annotated transcript of a real Claude Code ↔ Codex review loop over Engram |
| Tool compatibility map | The 19-tool v1 surface; every retired tool and its exact replacement |
| Backup & restore | Tested SQLite backup/restore/compaction runbook |
Status
Published. @tomcat65/engram-mcp@0.1.0 is live on the npm registry and the source is public at github.com/tomcat65/engram. The install path is contract-tested and was smoke-verified post-publish on a clean machine: npx -y @tomcat65/engram-mcp resolves the bin, and the first-run wizard runs straight from the registry install.
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 | lock-verify (manifest-bound pin matched), clean npm ci, script-integrity, typecheck, build, tests (33 files, 408 passed | 2 skipped | 6 todo), schema-docs, final-tree smoke, docker build — all PASS, exit 0 | this repository, internal/run-staged-proof.sh | 2026-07-16 |
| Documented env boots the runtime | Final-tree smoke gate: server starts from .env.example variables with a generated key, authenticated MCP request succeeds, DB lands at the documented path, bridge round-trips on the same contract, compose ports are loopback-bound, and the untouched placeholder key fails startup | this repository, internal/final-tree-smoke.mjs | 2026-07-16 |
| resume/checkpoint + conflict handling implemented | ENG-4 P0 contract suite (120 executable tests: CAS branching, conflict heads, idempotent replay, budget coverage closedness, scope-bound handles) | tests/contract-eng4-p0.test.ts | 2026-07-16 |
| Install path works | CLI contract suite (9 tests: bin mapping, wizard key-gen + parseable configs, .env write-once, live demo round-trip verified server-side, bridge delegation) | tests/contract-cli.test.ts | 2026-07-16 |
| Closed-safe defaults | Placeholder key fails startup; compose ports loopback-bound; CORS grants no cross-origin access unless CORS_ORIGINS is set (tested) | internal/final-tree-smoke.mjs, tests/contract-cli.test.ts | 2026-07-16 |
| Discovery is truthful | tools/list advertises the exact frozen schemas the handlers implement; retired legacy shapes are schema-rejected (regressions added after an adversarial review caught drift) | tests/contract-eng4-p0.test.ts | 2026-07-16 |
| Published + installable from the registry | npm publish succeeded under 2FA (auth-and-writes, security key); npm view @tomcat65/engram-mcp version → 0.1.0; clean-machine smoke: fresh npx cache, npx -y @tomcat65/engram-mcp --help and … init ran from the registry install | npm registry, post-publish smoke | 2026-07-16 |
v1 surface (short)
- Install (two-component setup): server via
docker compose up, then the@tomcat65/engram-mcpstdio bridge per MCP client; first-run wizard generates the API key and prints ready-to-paste 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.
- 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.- ACP: the coordination protocol as a versioned spec + real worked example.
