OpenChamber Engram Memory Browser Plugin

A read-only OpenChamber extension that browses and searches Engram memories for the active project. Recent context, project-scoped search, and full observation detail are rendered as sanitized HTML/Markdown, with copy and insert-to-chat actions.

Features

• Recent — renders the mem_context document (display-only bullets, no ids) as Markdown.
• Search — project-scoped mem_search with a match toggle (all/any) and a result limit (10/20).
• Detail — full observation (mem_get_observation) rendered as sanitized HTML; Markdown headings, lists, tables, code, blockquotes, links, images.
• Copy / Insert — copy the raw observation or insert it into the chat composer.
• Project bound — ownership is enforced service-side from the observation's Project: line; cross-project memories return a project-mismatch error.
• Read-only — only read tools are exposed; nothing is ever written to the Engram store.

Requirements

• OpenChamber 1.x — >=1.22.0, verified on 1.24.2. OpenChamber 2 is not supported.
• Engram >=2.0.0 — the engram executable must be on PATH (extension checks the version; older versions get an explicit unsupported-version state).

Install

From Settings → Extensions → Add:

1. Folder — add this repository root. Folder installs run from your folder, so you can edit, rebuild, and reload without re-installing.
2. Local ZIP — zip the repo and add the file (source: "zip").
3. HTTPS Git/ZIP URL — OpenChamber copies the build into its data folder; append #branch-or-tag to pin a ref.

After install, approve the service capability in the extension card. The service is spawned on the first request (status stopped → starting → ready; ready means GET /health returns 200). The panel connects automatically; if it cannot, use the card's setup screen to point the extension at the right executable/data directory.

Build from source

The sandbox frame cannot load ES modules, so panel/main.js must be a built classic IIFE.

bun install
bun run bundle:panel    # panel/main.ts -> panel/main.js (IIFE)
bun run bundle:service  # service/main.ts -> service/main.js (node)
bun run bundle          # both

• OpenChamber never compiles your code — you build main.js yourself (openchamber-guest-bundle).
• After rebuilding the service, restart it by pausing and re-enabling the guest (Settings → Extensions, or PUT /api/guests/engram-memory/enabled).
• The panel script is served statically by the host, so a browser reload picks up a new bundle without a service restart.

Configuration

Guest storage key config/v1 (set from the extension settings or panel setup screen):

Key	Default	Effect
executable	engram	Path to the Engram binary
dataDir	(unset)	Sets ENGRAM_DATA_DIR for the service
projectOverride	(unset)	Sets ENGRAM_PROJECT for the service

The Engram child is always spawned with mcp --tools=agent,admin so read-only admin tools (mem_timeline, mem_stats) are discoverable; every other tool call is rejected by the service.

Service API

Loopback HTTP service, authenticated with Authorization: Bearer <OPENCHAMBER_SERVICE_TOKEN>.

Route	Purpose
/v1/connect	Spawn Engram, version check, project info
/v1/recent	Display-only mem_context document
/v1/search	Project-scoped mem_search hits
/v1/getMemory	Full observation Markdown for an id
/v1/disconnect	Kill the child and shut down

All replies are { ok: true, ... } on success or { ok: false, code, message } on failure. Codes: no-context, empty-query, project-mismatch, invalid-id, read-failed, unsupported-engram, service-error.

Security notes

• The service listens on loopback only and requires the host-minted bearer token on every request, including /health.
• The extension requests only the service capability; it has no filesystem, network, or prompt grants.
• Read operations are an allowlist enforced in the service (mem_current_project, mem_list_projects, mem_context, mem_search, mem_get_observation, mem_timeline, mem_stats). Read-only MCP calls make no durable writes to the Engram store.
• Ownership of a mem_get_observation result is taken from the Project: line in the result text — never the process envelope — so you only ever see memories from your active project.
• As with any OpenChamber service, there is no sandbox: the allowed service runs with the user's full access (the grant card says so).

Repository layout

panel/        Frontend: index.html, main.ts (UI), markdown.ts (renderer), main.js (built)
service/     Backend: main.ts (HTTP service + MCP client), main.js (built)
adr/          Architecture Decision Records
fixtures/     Wire fixtures captured from Engram 2.0.0

Design decisions are recorded as Architecture Decision Records in adr/.

Contribute

Please feel free to fork and extend existing or add new features and send a pull request with your changes! To establish a consistent code quality, please provide unit tests for all your changes and adapt the documentation.

Want To Contribute?

If you feel that you have something to share, then we’d love to have you.

License

The OpenChamber Engram Memory Browser Plugin is released under the MIT License.