LangQuant

Hold the state of a conversation outside the chat.

LangQuant is experimental Python software for conversing with a local LLM from an explicit, refreshable language state instead of replaying the transcript on every turn.

The conversational model receives only the current state and the current message. A second model reads the latest exchange and prepares the next state. The transcript can remain visible to the human without becoming model input.

current language state + current message
                    │
                    ▼
          conversational model ────► reply
                    │                  │
                    └──── state updater┘
                               │
                               ▼
                     next language state

transcript ──► human interface only

A transcript records what happened. LangQuant keeps a working description of what matters now: the goal, decisions, facts, constraints, unresolved threads, vocabulary, and other explicit session state.

What this enables

• A different kind of local conversation. Inspect, save, edit, and restore the state that moves the conversation forward.
• State and compaction experiments. Change the schema, updater, model pair, or budget and observe what survives across turns.
• A primitive for internal tools. Put an explicit state boundary between a conversational model and the rest of an application.
• Research on language as operational state. Study when a language scaffold is adequate, what it omits, and how state updates fail.

LangQuant is not a vector database, transcript search engine, user-profile store, or production memory layer. It is a small state-transition mechanism you can run and inspect.

Quick start

Requirements: Python 3.11+ and a running Ollama service.

python3 -m venv .venv
source .venv/bin/activate
pip install langquant

ollama pull qwen3.5:9b
ollama pull qwen3.5:4b

langquant --goal "Plan a small API change"

Inside the conversation:

/state             show the exact state for the next model call
/transcript        show the human-facing transcript
/save state.json   save the current state
/quit              end the session

Try /state before and after a message. The change you see is the context that carries forward; earlier chat messages are not replayed to the conversational model.

Use it from Python

from langquant import LangQuantSession

session = LangQuantSession(
    main_model="qwen3.5:9b",
    state_model="qwen3.5:4b",
    approx_token_budget=7000,
)

session.configure(
    role="senior backend engineer",
    style="direct, concise, technical",
    goal="design a rate limiter for a payments API",
    constraints=["no Redis"],
)

reply = session.chat("We decided to use a token bucket.")
print(reply)

print(session.show_state())
session.save_state("state.json")

The saved state is ordinary JSON. It can be inspected, versioned, edited, or loaded into a later session.

from langquant import LangQuantSession

session = LangQuantSession()
session.load_state("state.json")
print(session.chat("What should we decide next?"))

The state transition

For turn t, LangQuant has the following operational shape:

reply_t       = conversational_model(state_t, message_t)
state_(t + 1) = state_updater(state_t, message_t, reply_t)

The prior transcript is not an argument to either call. In that narrow architectural sense, this is a first-order state-transition loop.

That shape does not establish that the current state contains everything a conversation could need. State adequacy is the research question. An updater can omit, distort, or misclassify information, and different schemas will preserve different things.

What is in the state?

The reference schema is typed and deliberately legible:

The state updater proposes a JSON delta after each exchange. LangQuant applies that delta and renders the result as the next plain-language scaffold.

Inspect the boundary

The request-boundary tests use mocked model calls, so they do not require Ollama:

python -m pytest -q
ruff check .

The focused tests verify that UI transcript content is absent from the conversational-model request and from the following state-update request. They also exercise graceful behavior when the local model service is unavailable.

The repository includes exploratory conversation and scaffold experiments. Read the experiment record for their design, defects, and exact claim limits. Those artifacts are research material, not a benchmark claim that this approach outperforms summaries, retrieval, or full transcripts.

Project status

LangQuant is an alpha research prototype. The useful, inspectable result today is the mechanism itself: a local conversation can be wired through explicit current state while keeping prior messages out of the conversational-model request.

Good contributions include stronger state schemas, validated state deltas, deterministic evaluation, exact budget enforcement, model-provider adapters, and tools for comparing state against the transcript it replaces.

See the contribution guide to contribute.

License

Apache 2.0.