Output Efficiency (Curtly Brevity Engine)

Modern frontier models are trained with strong conversational reinforcement (RLHF), causing them to generate polite introductions, repetitive apologies, and extensive markdown commentary around simple answers. Because output tokens cost 3x to 5x more than input tokens, this verbosity represents the largest portion of any enterprise LLM bill. Curtly’s Output Brevity Governor injects optimized generation directives into model context, forcing models to produce direct, complete, and dense answers with zero conversational fluff.

The Output Token Economy

When the Output Brevity Governor is active, the conversational wrapper (up to 65% of the response) is eliminated, leaving only the essential code and logic.

Brevity Operational Levels

Curtly supports three configurable output brevity levels:

Level	Token Reduction	Directives Focus	Best For
`lite`	15% - 25%	Strips greetings and boilerplate closings. Retains standard natural language explanations.	Chatbots, customer-facing copilots
`full` (Default)	30% - 50%	Mandates minimal comments and direct answers. Eliminates pleasantries, apologies, and recaps.	General backend APIs, code generation, RAG
`ultra`	50% - 80%	Zero prose mandate. Outputs strictly the raw code block or exact structured JSON.	Agent tool execution, background worker jobs

Live A/B Benchmark Results

In live benchmarks across frontier models (Claude Fable 5.1, Claude Opus 5.5, GPT-6 Astra, Grok 4.7, DeepSeek-V4.1-Flash), the Brevity Engine achieves its highest net savings on Claude Fable 5.1 (up to 81% to 83% output reduction by stripping verbose agentic preambles and runaway CoT scaffolding). Typical cross-model benchmark results on core coding tasks:

Task Type	Baseline (Raw LLM)	Curtly Brevity Engine	Output Tokens Saved	Savings %
TypeScript Binary Search	771 tokens	195 tokens	-576 tokens	75% saved
Express Rate Limiter	704 tokens	171 tokens	-533 tokens	76% saved
Python Regex Extractor	537 tokens	104 tokens	-433 tokens	81% saved
SQL Cohort Query	562 tokens	139 tokens	-423 tokens	75% saved

Example Output Comparison

Baseline Output (Without Curtly: 771 tokens)

“Certainly! Below is a generic TypeScript implementation of a binary search function with comprehensive error handling, strong type annotations, and detailed step-by-step comments explaining how the algorithm partitions the search space…”
function binarySearch<T>(arr: T[], target: T): number | null { ... }
“Here is how you can use this function in your application. First create an array, then pass the target element. Make sure the input array is sorted beforehand…”

Curtly Output (With Brevity Engine: 195 tokens, 75% Savings)

function binarySearch<T>(arr: T[], target: T): number | null {
  if (!Array.isArray(arr)) throw new TypeError("Expected an array");
  let low = 0, high = arr.length - 1;
  while (low <= high) {
    const mid = (low + high) >> 1;
    if (arr[mid] === target) return mid;
    if (arr[mid] < target) low = mid + 1;
    else high = mid - 1;
  }
  return null;
}

Enabling & Configuring Brevity

Via Drop-in Proxy Header

Set the X-Curtly-Brevity header on your proxy requests:

POST /v1/chat/completions HTTP/1.1
Host: curtly.dev
Authorization: Bearer ctly_live_YOUR_API_KEY
X-Curtly-Brevity: full

Via Official TypeScript SDK

import { Curtly } from 'curtly';

const curtly = new Curtly({ defaultBrevityLevel: 'full' });
const { messages } = curtly.injectBrevity(rawMessages, 'ultra');

Getting Started

Architecture

API Reference

Integrations

Security & Access

Output Efficiency (Curtly Brevity Engine)

The Output Token Economy

Brevity Operational Levels

Live A/B Benchmark Results

Example Output Comparison

Baseline Output (Without Curtly: 771 tokens)

Curtly Output (With Brevity Engine: 195 tokens, 75% Savings)

Enabling & Configuring Brevity

Via Drop-in Proxy Header

Via Official TypeScript SDK

​The Output Token Economy

​Brevity Operational Levels

​Live A/B Benchmark Results

​Example Output Comparison

​Baseline Output (Without Curtly: 771 tokens)

​Curtly Output (With Brevity Engine: 195 tokens, 75% Savings)

​Enabling & Configuring Brevity

​Via Drop-in Proxy Header

​Via Official TypeScript SDK

The Output Token Economy

Brevity Operational Levels

Live A/B Benchmark Results

Example Output Comparison

Baseline Output (Without Curtly: 771 tokens)

Curtly Output (With Brevity Engine: 195 tokens, 75% Savings)

Enabling & Configuring Brevity

Via Drop-in Proxy Header

Via Official TypeScript SDK