Vision Pipeline

analyzeWithThreePassPipeline(pdfBuffer, prompt, processorType, page)
    │
    ├── Pass 1: callGeminiPro3Vision() ──► Gemini 3 Pro Preview
    │     Fast visual extraction, ThinkingLevel.LOW, 8192 tokens
    │
    ├── Pass 2: callGeminiVision() ──► Gemini 2.5 Pro
    │     Validates Pass 1, fills gaps, thinkingBudget: 1024
    │
    ├── Pass 3: callOpusInterpretation() ──► Claude Opus 4.6
    │     Text-only validation, correction, enrichment
    │     Fallback: callGPT52Interpretation() ──► GPT-5.2
    │
    └── Full fallback: analyzeWithSmartRouting()
          Routes by document classification (visual/text-heavy/mixed)

Smart Routing

analyzeWithSmartRouting(pdfBuffer, prompt, processorType)
    │
    ├── 'visual' ──► Rasterize → analyzeWithLoadBalancing()
    │                  Fallback: analyzeWithDirectPdf(VISION_MODEL)
    │
    ├── 'text-heavy' ──► analyzeWithDirectPdf()
    │                      Fallback: Rasterize → analyzeWithLoadBalancing()
    │
    └── 'mixed' ──► analyzeWithDirectPdf() first
                     Fallback: Rasterize → compare quality scores

Core Patterns

Provider Configuration

// lib/vision-api-multi-provider.ts
type VisionProvider = 'gemini-3-pro-preview' | 'gemini-2.5-pro' | 'claude-opus-4-6' | 'gpt-5.2' | 'claude-sonnet-4-5';

const PROVIDERS: ProviderConfig[] = [
  { name: 'claude-opus-4-6', maxRetries: 3, baseDelay: 1000 },
  { name: 'gpt-5.2', maxRetries: 3, baseDelay: 1000 },
  { name: 'claude-sonnet-4-5', maxRetries: 3, baseDelay: 1000 },
];

PDF Detection and Native Processing

// Claude supports native PDF via document type
export function isPdfContent(base64: string): boolean {
  return base64.startsWith('JVBERi');  // %PDF- magic number
}

// PDF content always routes to Opus (no GPT-5.2 fallback for PDFs)
if (isPdf) {
  logger.info('VISION_API', 'PDF native content — using Claude Opus');
}

Timeout Strategy

Quality Validation

// lib/vision-api-multi-provider.ts — validateQuality()
function validateQuality(content: string): QualityMetrics {
  let score = 0;
  if (/sheet[\s-]*\w+/i.test(content)) score += 30;     // Has sheet number
  if (content.length > 200) score += 30;                  // Substantial content
  if (content.includes(':') && content.includes('{')) score += 40;  // Structured data
  return { score, hasSheetNumber, hasContent, hasStructuredData, contentLength };
}

Minimum quality threshold: 50 (default). Content failing quality check triggers fallback to next provider.

Three-Pass Pipeline Details

Pass 1 — Gemini 3 Pro Preview (Extraction)

• Model: gemini-3-pro-preview
• Purpose: Fast, cheap visual extraction of raw JSON
• Config: maxOutputTokens: 8192, temperature: 0.1, thinkingLevel: LOW
• Sees: The image/PDF directly

Pass 2 — Gemini 2.5 Pro (Validation)

• Model: gemini-2.5-pro
• Purpose: Validates Pass 1 output, fills gaps
• Config: maxOutputTokens: 8192, temperature: 0.1, thinkingBudget: 1024
• Sees: The image/PDF AND Pass 1's JSON output

Pass 3 — Opus/GPT Interpretation (Text-Only)

• Model: claude-opus-4-6 (fallback: gpt-5.2)
• Purpose: Correct errors, enrich metadata, add confidence scores
• Sees: JSON only (no image) — purely text validation
• This is the cheapest pass since no vision tokens are consumed

Cost per Page

Retry and Backoff

All providers use exponential backoff: baseDelay * 2^retryCount

// Exponential backoff pattern used across all providers
if (retryCount < config.maxRetries) {
  const delay = config.baseDelay * Math.pow(2, retryCount);
  await new Promise(resolve => setTimeout(resolve, delay));
  return callProvider(imageBase64, prompt, retryCount + 1);
}

Special cases:

• Cloudflare blocks: immediate failover (no retry)
• Timeouts on Opus PDFs: one retry, then fail
• GPT-5.2 PDF content: fail fast (no PDF support)
• Gemini safety blocks: no retry

Load Balancing

// Round-robin across Opus and GPT-5.2 for images
let providerRoundRobinIndex = 0;
function getNextProviderIndex(): number {
  const index = providerRoundRobinIndex % PROVIDERS.length;
  providerRoundRobinIndex = (providerRoundRobinIndex + 1) % PROVIDERS.length;
  return index;
}
// PDFs always use Opus (skip round-robin)

Configuration

Key Files

Pipeline Mode

type PipelineMode = 'discipline-single-pass' | 'three-pass-legacy';
// Controlled by env var PIPELINE_MODE, defaults to 'discipline-single-pass'

Anti-Patterns

• Never send PDFs to GPT-5.2 — it does not support native PDF content
• Never skip quality validation — low-quality extractions propagate bad data to RAG
• Never hardcode timeouts — use the provider config constants
• Never retry on Cloudflare blocks — switch providers immediately
• Never use Sonnet for active vision — it is a secondary fallback only

Quick Reference

import { analyzeWithLoadBalancing, analyzeWithSmartRouting, analyzeWithDirectPdf } from '@/lib/vision-api-multi-provider';

// Single image analysis (chat)
const result = await analyzeWithLoadBalancing(imageBase64, prompt, pageNumber);

// PDF with smart routing (batch)
const result = await analyzeWithSmartRouting(pdfBuffer, prompt, 'claude-opus-vision', pageNumber);

// Direct PDF processing
const result = await analyzeWithDirectPdf(pdfBase64, prompt, startPage, endPage);