dbl-gateway 0.4.1

DBL Gateway

DBL Gateway

This repository provides a deterministic execution boundary for LLM calls.

It enforces an explicit separation between request, decision, and execution, and records every interaction as an append-only, replayable event stream.

This is not:

• an agent framework
• a RAG pipeline
• a workflow engine
• a UI product

The gateway does not decide what to do. It decides whether an explicitly declared action may execute.

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Repository Landscape

The gateway is part of a small toolchain:

dbl-gateway (this repository)

Authoritative execution boundary and event log. The gateway is authoritative for execution, but not for interpretation. It emits facts, not narratives.

• Accepts explicit intents.
• Applies policy.
• Executes provider calls.
• Emits canonical events (INTENT, DECISION, EXECUTION).
• Persists an append-only event trail.
• Exposes read-only observation surfaces (/snapshot, /tail).

dbl-operator

Observer and intervention client. Used for rendering timelines, audits, and decision views. Does not evaluate policy or store authoritative state.

dbl-chat-cli

Minimal interactive CLI client for smoke testing and quick interaction via terminal.

dbl-chat-client

Pure event-projection UI. Real-time visualization of the gateway event stream and identity anchor management.

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Interaction Model

Every interaction follows the same sequence:

1. INTENT – explicit request with identity anchors (thread_id, turn_id).
2. DECISION – policy outcome (ALLOW/DENY).
3. EXECUTION – provider call and result.
4. OBSERVATION – read-only access via snapshot or tail.

Only DECISION events are normative. EXECUTION events are observational and cannot influence policy or state.

No step is implicit; every event is linked via a stable correlation_id.

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Design Principles

• Explicit boundaries: Strict separation between core logic, policy, and execution.
• Append-only records: Immutable event trail for audit and replay.
• No hidden state: No heuristics or internal memory beyond the event stream.
• Observer-safe: Clients may observe and project state, but cannot affect policy, execution, or event ordering.

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Context System (v0.4.0+)

The gateway supports explicit context declaration for multi-turn conversations.

declared_refs

Clients can reference prior events as context via IntentEnvelope.payload.declared_refs:

{
  "declared_refs": [
    {"ref_type": "event", "ref_id": "correlation-id-1"},
    {"ref_type": "event", "ref_id": "turn-id-2"}
  ]
}

These references are resolved by the gateway and injected into the LLM context as a deterministic system block. This allows for multi-turn conversations without the gateway implicitly managing history.

I_context / O_context Split

Type	Admitted For	Digest Scope	Policy Access
INTENT events	governance	✅ Included	✅ Yes
EXECUTION events	execution_only	✅ Included (audit)	❌ No

This ensures observations never influence governance decisions (DBL Claim 4).

Configuration

Context behavior is controlled by config/context.json:

{
  "max_refs": 50,
  "empty_refs_policy": "DENY",
  "canonical_sort": "event_index_asc",
  "enforce_scope_bound": true
}

The config digest is pinned in every DECISION event for replay verification.

See docs/CONTEXT.md for the full specification.

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Installation

Local Install

Create a virtual environment and install the gateway:

pip install .

Docker

The gateway can be started with a single Docker command. No interactive setup, no hidden defaults.

docker build -t dbl-gateway .
docker run -p 8010:8010 \
  -e OPENAI_API_KEY="sk-..." \
  -e DBL_GATEWAY_POLICY_MODULE="dbl_policy.allow_all" \
  dbl-gateway

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Running the Gateway

Required Environment Variables

Variable	Description
OPENAI_API_KEY	Provider API key.
DBL_GATEWAY_POLICY_MODULE	Policy module (e.g., dbl_policy.allow_all).
DBL_GATEWAY_POLICY_OBJECT	Policy object inside the module (default: policy).

Start Command

dbl-gateway serve --host 127.0.0.1 --port 8010

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Observation Surfaces

Snapshot (/snapshot)

Returns a point-in-time state of the event log. Suitable for audits and offline inspection.

Tail (/tail)

A live SSE stream of events.

• since: Start streaming from a specific event index.
• backlog: Number of recent events to emit on connect (default: 20).

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Integration Examples

Using the Operator

$env:DBL_GATEWAY_BASE_URL = "http://127.0.0.1:8010"
dbl-operator thread-view --thread-id t-1

Using the Chat CLI

dbl-chat-cli --base-url http://127.0.0.1:8010 --principal-id user-1

Using the Chat Client

# In the dbl-chat-client repository:
npm install && npm run dev

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Status

Early, but operational. Core execution, policy gating, and auditing are stable. Current focus: surface stabilization and contract clarity.