Skip to main content

What's New in Loopers

Stay up to date with the newest capabilities we've added to the Loopers cost firewall.

Transient Session Buffer (Stateful Tracing)​

Operators can now evaluate actual request and response text payloads (prompts, completions, tool inputs, and tool outputs) in OPA/Rego and Declarative YAML policies. Loopers captures execution history dynamically in Redis as JSON-serialized events under input.session.traces.

To protect user privacy and avoid memory bloat, all stored prompt/response payloads are strictly truncated to 512 characters, and the history is capped at the 15 most recent entries (managed via Redis LPUSH/LTRIM). This enables advanced multi-turn policy enforcement (e.g., "block file writes if a database query returned confidential customer data earlier in the session") while maintaining Loopers' zero-storage-on-disk guarantee.

Stateful Session Context (Taint Tracking)​

OPA policies can now evaluate the historical execution trace of a session. Loopers passes input.session.taint_flags and input.session.tools_called to OPA before every request. Whenever sensitive tools (such as read_secret, get_credentials, vault_read) are invoked, Loopers automatically sets session taint flags (e.g. secret_accessed). This enables cross-call data exfiltration prevention rules such as: "if secret_accessed taint is set in step 2, block all outbound_http calls in step 5".

Agent-Friendly Policy Denial Formats (Self-Correction)​

When an OPA policy blocks an MCP tool call, Loopers now returns a valid MCP JSON-RPC 2.0 error object at HTTP 200 (code -32001) with the X-Loopers-Policy-Block: true header. Most agent frameworks (LangChain, AutoGen, CrewAI) surface this to the LLM as a tool failure message rather than crashing on an HTTP 403 exception, allowing the LLM planner to self-correct its strategy in real-time. SDK wrappers for Python and TypeScript also include LoopersPolicyDenied, parse_policy_denial(), and onPolicyBlock callbacks.

Fuzzy Bi-Gram Jaccard Agent Loop Detection​

We've completely overhauled our agent loop detection engine. Exact-hash detection (like FNV-1a) is often easily bypassed by modern LLMs and agents that slightly mutate their prompts when stuck in a loop (e.g., adding attempt counters or subtle rephrasing). Loopers self-hosted v1.1+ now uses Bi-Gram Jaccard Similarity to compare request token sets. It calculates the exact structural similarity between prompts, allowing it to catch polymorphic, mutating agent loops that exact matching cannot. You can tune the sensitivity using the new similarity_threshold configuration (default 0.95).

Local Policy Engine (OPA/Rego)​

Loopers now includes an embedded Open Policy Agent (OPA) engine for fine-grained, attribute-based access control. Write .rego policies to govern which agents can access which models, block destructive MCP tools, and enforce environment-level restrictions — all evaluated at the network layer before any request is forwarded upstream. Policies are hot-reloaded within 500ms when files change, with zero downtime.

Agent Identity & Key Metadata​

Every proxy key can now carry rich identity metadata including agent_name, owner, allowed_tools, allowed_providers, and arbitrary tags (key=value pairs). This identity flows into policy evaluation, OpenTelemetry trace spans, and security event webhooks, enabling full audit trails and per-agent governance.

CrewAI & AutoGen Framework Adapters​

We have launched native Python SDK adapters for CrewAI and Microsoft AutoGen. Drop in get_loopers_crewai_llm() to return a LangChain ChatOpenAI instance routed through Loopers, or use get_loopers_autogen_config() to generate an AutoGen-compatible llm_config dictionary. All Loopers features — budget enforcement, loop detection, and policy evaluation — are applied automatically.

Per-Key Rate Limiting​

A new sliding window rate limiter powered by an atomic Redis Lua script allows you to cap request velocity per key, independent of budget limits. Configure rate_limit.requests_per_minute in your loopers.yaml to set the threshold. The limiter returns X-RateLimit-Remaining headers and emits structured rate_limit_block security events.

Model Context Protocol (MCP) Governance​

Loopers governs Model Context Protocol (MCP) traffic natively. We have shipped a transparent JSON-RPC 2.0 proxy that enforces per-tool cost budgets (e.g., $0.05 per Snowflake query, $0.001 per GitHub API call). It also features a deterministic tool-call circuit breaker to stop agents from executing infinite runaway loops. This feature establishes Loopers as the definitive enforcement layer for agentic workloads.

Local Lease Budget Guard Loop​

To provide high-throughput rate-limiting under extreme concurrent loads, Loopers utilizes a local lease/budget cache mechanism. It reserves a budget lease from Redis and performs atomic deductions locally in memory, keeping latency to 1-2 milliseconds. The background guard loop reconciles spent totals and blocks keys within seconds, keeping any potential concurrent budget leakage capped.

Security Events Webhooks​

Security and auditing just got much easier. You can now configure Loopers to POST structured security events directly to your SIEM or custom webhook endpoints. This allows security teams to instantly react to anomalies, budget breaches, or potential credential leaks without polling the database.

  • Configure: Set alerting.webhook_url in your loopers.yaml configuration.

OpenTelemetry (OTel) Tracing​

To help enterprises meet stringent compliance requirements (like the EU AI Act), Loopers now includes first-class OpenTelemetry support. When enabled, every prompt, response, and budget transaction is fully traced across your microservices architecture.

  • Configure: Set otel.enabled: true in your loopers.yaml configuration.

LangChain & LlamaIndex Native Adapters​

We have officially launched native drop-in adapters for both Python and TypeScript. You no longer need to manually construct HTTP requests to the Loopers proxy. You can just drop ChatLoopers into your LangChain workflow or LoopersLLM into your LlamaIndex pipelines with a single line of code.

Session Budgets​

Along with global provider limits, you can now define Session Budgets. This allows you to cap the exact amount of money a specific user, chat session, or autonomous agent can spend in a single run. Simply pass the session_id and session_budget headers!

15 Provider Integrations & Stable SDK Launch​

The initial stable release of Loopers marked the launch of our SDKs alongside native proxy support for 15 leading AI providers, including OpenAI, Anthropic, Google Gemini, Fireworks, Ollama, vLLM, and xAI.