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The reason capability provides access to large language models for text generation, analysis, and reasoning tasks.

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Providers

ProviderModels
OpenAIgpt-4o, gpt-4o-mini, gpt-4-turbo
Anthropicclaude-sonnet-4-20250514, claude-3-5-haiku

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Basic Usage

const result = await saturn.reason({
  prompt: 'Explain quantum computing in simple terms',
});

console.log(result.data.content);
// → "Quantum computing is a type of computation that..."

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Parameters

​
prompt
string
required
The text prompt to send to the LLM.
​
provider
string
Specific provider to use. If omitted, Saturn chooses the best available.
​
model
string
Specific model to use. Requires provider to be set.
​
systemPrompt
string
Optional system prompt for context.
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maxTokens
number
Maximum tokens in the response. Default varies by model.
​
temperature
number
Sampling temperature (0-2). Lower is more deterministic.

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Response

interface ReasonResponse {
  data: {
    content: string;        // Generated text
    finishReason: string;   // 'stop', 'length', etc.
    usage: {
      promptTokens: number;
      completionTokens: number;
      totalTokens: number;
    };
  };
  metadata: {
    chargedUsdCents: number;
    provider: string;
    model: string;
    latencyMs: number;
    auditId: string;
  };
}

​
Examples

​
Choose a Provider

// Use Anthropic specifically
const result = await saturn.reason({
  prompt: 'Analyze this code for bugs...',
  provider: 'anthropic',
  model: 'claude-sonnet-4-20250514',
});

​
With System Prompt

const result = await saturn.reason({
  systemPrompt: 'You are a helpful coding assistant.',
  prompt: 'How do I reverse a string in Python?',
});

​
Control Output Length

const result = await saturn.reason({
  prompt: 'Write a haiku about programming',
  maxTokens: 50,
  temperature: 0.7,
});

​
Pricing

Pricing is per-token and varies by model:
ModelInputOutput
gpt-4o$2.50/M tokens$10.00/M tokens
gpt-4o-mini$0.15/M tokens$0.60/M tokens
claude-sonnet-4-20250514$3.00/M tokens$15.00/M tokens
Saturn quotes the cost before execution. The quote is based on estimated tokens. Actual cost may be slightly different based on actual usage.

​
Error Handling

import { SaturnPolicyDeniedError, SaturnProviderError } from '@saturn-pay/sdk';

try {
  await saturn.reason({ prompt: 'Very long prompt...' });
} catch (err) {
  if (err instanceof SaturnPolicyDeniedError) {
    // Budget exceeded or capability not allowed
    console.log('Policy error:', err.message);
  } else if (err instanceof SaturnProviderError) {
    // Upstream provider error
    console.log('Provider error:', err.message);
  }
}