// AGENTIC RUNTIME

Fast & Efficient Agents that Scale

Every LLM call starts from zero. Harper fills the gap: full context assembled in milliseconds, up to 85% fewer LLM calls. Simple to deploy. Designed to replicate globally.
Illustration of an agent running directly in Harper, positioned above unified APIs (GraphQL, REST, WebSocket, MQTT). The agent operates within Harper’s fused stack, accessing cache and in-memory layers in-process for low-latency performance, alongside integrated data services including blob storage, database, NoSQL, and vector capabilities.
// TWO CHOICES

If cost and performance matter, there's only one path.

The teams winning in production aren't iterating on LLM-first architectures. They're building context-first from day one — faster for users, cheaper to operate, and better responses.

LLM-First

PROTOTYPE
Each tool call is a new trip through the LLM.
Customer chat LLM Order history Shopify API LLM Past emails Helpdesk API LLM Similar requests Vector search LLM Business rules Config / wiki LLM Response

Good For Demos

Fast to build with tool-calling frameworks. Works for simple, low-stakes queries. Breaks under complexity, cost, and latency pressure at scale.
5
LLM CALLS
4
TOOL ROUND TRIPS
10-20s
LATENCY
HIGH
TOKEN SPEND

Context-First

PRODUCTION
Deterministic context assembly before the first call.
Customer chat Unified Runtime All data co-located, in-process Semantic cache Resolved interactions Customer Profile + offers Active orders Status + proofs Business rules Turnaround, pricing Order history Previous transactions Assembled context payload Cache hit No LLM call. Return proven answer. New request LLM Single call, full context Response

Built For Production

Requires more structure upfront. Dramatically faster and cheaper at scale. Handles edge cases predictably. The model reasons over complete information, not fragments.
0-1
LLM CALLS
0
TOOL ROUND TRIPS
<50ms
ASSEMBLY
MINIMAL
TOKEN SPEND
// BY THE NUMBERS

Measure context assembly in milliseconds, not seconds.

1-10ms
Vector lookups in-process
<50ms
Full context assembly from multiple sources
65-85%
LLM call reduction on support workloads
1
Process. Database, cache, APIs, vectors, blob, real-time.
> What's the tallest building in the world?
LATENCY 5.2s · COST $0.0098 · WEB 1 search
> Which building is the tallest globally?
LATENCY 0.03s · CACHE HIT · $0.00 · saved $0.0098
LIVE DEMO

See Semantic Caching Cut Costs in Real Time

A conversational agent with vector memory, semantic caching, and local embeddings running entirely on Harper. Ask the same question twice. Watch the LLM call disappear.
// WHY A UNIFIED RUNTIME

The pattern is clear. The infrastructure needs to match it.

Context-first architectures need fast, parallel access to structured data, vector search, and business logic. When those live in separate services connected by APIs, you've replaced LLM round trips with network round trips. The simpler path: co-locate agents and the data they depend on in one runtime.
FEWER TOKENS

Cut LLM Spend by Up to 85%

Every resolved interaction is vectorized and stored. When a similar request comes in, the runtime returns a proven answer without touching the LLM. For the rest, deterministic routing and rich context mean fewer calls and shorter loops.
SPEED

Sub-50ms Context Assembly

No network hops between services. No serialization overhead. Customer records, order history, vector search, and business rules queried in parallel, in the same memory space.
SECURITY

Smaller Attack Surface

One process, one runtime. No API keys scattered across services. No orchestration layer bridging disconnected systems. Data stays co-located, not spread across the network.
LLM FREEDOM

Don't Lock Into One LLM

When agents are managed separately from the LLM, the model becomes a commodity. Switch providers. Negotiate pricing. Use different models for different tasks.
EDGE-READY

Replicate Everywhere

A self-contained runtime is designed for replication. Run your agent with its full data context in 2, 10, or 20 locations. Global speed, local intelligence.
SIMPLICITY

Dev to Prod, Same Surface

What you build locally is what you deploy. One self-contained runtime. No infrastructure to wire together between prototype and production.
// ARCHITECTURE

Everything your agent needs in one process.

In most stacks, these components live in separate services. Here, they run in the same process. Structured data, vector embeddings, caching, real-time pub/sub, REST API, and your application logic in a single Node.js runtime.
DATA SOURCES
Webhooks
CRM
ERP
Commerce
Email
HARPER RUNTIME
Database
Vector Search
Cache
Real-Time
REST API
AGENT LAYER
Context Assembly
Semantic Cache
Deterministic Routing
Escalation Rules
Business Logic
LLM (ANY)
Claude
GPT
Gemini
Open Source
MULTI-REGION DEPLOY
Harper Fabric (Managed)
// GO DEEPER

The architecture and the math.

Two deep dives that break down why production systems are converging on this pattern, and what it means for your LLM bill.

Start building your agent in minutes.

Build a production-ready system without stitching together five services.
npm create harper@latest CLICK TO COPY