Librarian

Librarian is an RPC-native fork of Understory. It preserves Understory's deterministic Open Knowledge Format bundle and high-level MCP contract while delegating agentic work to an existing agent harness. Hermes Agent is the default backend; OMP is an optional backend selected with LIBRARIAN_AGENT_BACKEND=omp.

There is no embedded model provider, API client, or second agent loop. Hermes uses its native TUI-gateway JSON-RPC protocol. OMP uses its distinct native JSONL RPC protocol.

What stays deterministic

Every deep read and mutation crosses the private librarian-okf MCP boundary. Understory's KnowledgeBase remains the only write path, so it still enforces:

• bundle-relative path sandboxing;
• required OKF frontmatter;
• generated index.md files;
• newest-first log.md entries;
• serialized mutations;
• optional Git autocommits.

The public MCP retains Understory's original tools:

• memory_query
• memory_add
• memory_update
• memory_status
• memory_maintain

memory_status is model-free. Every deep operation starts a fresh isolated agent turn, streams native tool events internally, and closes the worker after the final answer.

Layered memory and dreaming

The current upstream cache and dreaming work is included without restoring Understory's embedded model provider:

1. an exact query cache is keyed by the bundle fingerprint, backend, model, provider, and normalized question;
2. a short-lived hot set checks recently changed concepts and recent answers;
3. a miss delegates to the full Librarian agent and its private OKF tools.

Any bundle change invalidates exact answers. Hot answers are accepted only when the selected harness returns a tool-free response; otherwise the request falls through to the deep agent.

The optional persistent web service also runs conservative memory consolidation. It checks every six hours by default, with the first check delayed ten minutes after startup. Set DREAM_INTERVAL to another duration or to off; set DREAM_START_DELAY independently when a different first-check delay is useful. Checks are scheduled only after the preceding run finishes, never overlap, and do not run in ephemeral stdio MCP processes. A dream runs against an isolated copy of the bundle and saves a pending proposal; it never changes live memory by itself. The fresh Hermes or OMP process passes a process-local bundle override to its private librarian-okf MCP, so the agent's actual read/write tool calls are confined to that copy without rewriting either harness profile. Only one pending proposal is permitted, so an unattended scheduler cannot accumulate competing plans against the same baseline.

The web UI's Dreams view auto-refreshes proposal history and scheduler state, shows the next and previous checks, highlights changed lines in every exact before/after diff, and confirms each apply/reject/rollback action. Only the human-only HTTP approval route can resolve a proposal; no model-facing MCP tool has approval authority. Approval first verifies both the stored proposal hashes and every live concept baseline. Applied proposals retain their preimages and can be rolled back from the same view, while a later concept change blocks rollback rather than overwriting newer knowledge. Interrupted multi-file apply or rollback operations compensate completed edits and retain an explicit error when compensation cannot fully restore the prior state. This adapts Prime Agent's plan/apply/rollback refinement lifecycle and LongHorizon-Harness' persisted human gate without adding another agent loop. All web dream controls require AUTH_TOKEN; without it proposals are read-only and the control routes fail closed. The UI's Deauthorize action forgets its browser-local bearer token; the server remains stateless.

Setup

Requirements:

• Bun, normally supplied by Sandwich;
• either a configured native hermes installation or a configured omp installation;
• a reachable model in the selected backend/profile;
• Git for updates and optional OKF autocommits.

Node.js, npm, pnpm, npx, and yarn are not runtime requirements. Source imports using the node:* namespace run through Bun's compatibility APIs.

git clone https://github.com/CommanderTurtle/librarian.git
cd librarian
bun run setup

Setup asks for the delegated backend, OKF bundle, model, and provider, then builds the Bun workspace and writes resolved paths to .env.

Hermes backend (default)

Setup clones the current Hermes profile into an isolated librarian profile, registers librarian-okf only in that child profile, and registers the public librarian MCP in the default profile. This prevents recursive memory_* calls while preserving Hermes as the sole agent loop.

Rerunning setup refreshes both registrations without recreating the profile. Non-default installations can set HERMES_HOME, HERMES_PROFILE_HOME, and HERMES_PYTHON.

OMP backend

Set LIBRARIAN_AGENT_BACKEND=omp before setup or select omp at the prompt. Setup follows OMP's native profile-scoped MCP configuration:

• the public librarian MCP is merged into ~/.omp/agent/mcp.json;
• the dedicated ~/.omp/profiles/librarian/agent/mcp.json is converged to the private librarian-okf server only;
• delegated workers launch as omp --profile librarian --mode rpc --no-session.

The two profile files are deliberately separate. Rerunning setup removes stale MCP registrations from the dedicated worker profile but never prunes the normal OMP profile. The worker therefore cannot discover its own public memory_* server or recurse back into Librarian. Setup also repairs an old OMP_AGENT_DIR value that accidentally points into a named profile. Override OMP_HOME, OMP_AGENT_DIR, OMP_PROFILE_AGENT_DIR, OMP_PROFILE, or OMP_COMMAND for a non-default layout. OMP_MODEL plus OMP_PROVIDER select a model explicitly; blank values inherit the active OMP profile.

Librarian makes no telemetry calls of its own. Knowledge, traces, delegated sessions, and configuration remain on the machine running the chosen harness.

Optional web browser

The MCP servers are stdio processes and require no persistent Librarian service. To browse the OKF tree, graph, traces, dream proposals, and chat through the selected backend:

./start.sh

The default address is http://localhost:3800. Set AUTH_TOKEN to enable the Dreams view's propose/approve/reject/rollback controls, and always before exposing the service beyond a trusted host or LAN. Only this persistent process runs the optional dream scheduler. Native Hermes and OMP RPC usage is attached to traces when the selected harness reports it.

Update

./update.sh

The update path rebases the Librarian repository with an autostash, performs a frozen Bun install, and rebuilds every package. Run bun run setup once after installing this dreaming update so the scheduler defaults and the exact private MCP boundary are written. Later reruns are needed only when paths, backend, profile, model, or MCP registrations change.

Development

The repository is a private Bun workspace even though its source is public. Internal @understory/* package names preserve the upstream module boundary; they are not published packages.

bun install --frozen-lockfile
bun test
bun run build

origin is the Librarian repository. Understory remains upstream so its work can be reviewed and merged deliberately:

git fetch upstream --prune
git log --oneline --left-right main...upstream/main

Setup and update scripts never pull Understory implicitly.

Architecture

Hermes default profile                    OMP default profile
  └─ librarian MCP (memory_*)               └─ librarian MCP (memory_*)
       └─ fresh TUI-gateway process               └─ fresh OMP RPC process
            └─ isolated librarian profile              └─ isolated librarian profile
                 └─ librarian-okf MCP                        └─ librarian-okf MCP
                      └─ Markdown OKF bundle                       └─ Markdown OKF bundle

Query traces stay local under <bundle>/.traces/. Dream proposals and their preimages stay local under <bundle>/.librarian/dream-proposals/; the bundle walker ignores this internal directory.

License

AGPL-3.0-only. Librarian is a modified derivative of Understory by Anirban Kar. See NOTICE for upstream attribution and LICENSE for the complete license.