Character counts won't predict PDF input tokens — bracket the cost per page before you send
How to estimate the input tokens of a PDF before sending it to the Claude API, by bracketing from page count rather than character count. Includes a measured 6.6x gap on a nine-page A4 document, the two separate increases that come with current models, and the count_tokens limitation that bites when you use file_id.
Claude Vision API in Production — Implementation Patterns for Image Analysis, PDF Processing, and OCR
Implementation patterns for taking Claude's vision capabilities to production: choosing between Base64, URL, and the Files API, native PDF processing, schema-enforced extraction with Tool Use, batch cost reduction, and error recovery — all with working code.
Complete Fix Guide: Claude File Attachment and Image Recognition Failures
Solve issues where PDFs, images, or text files attached to Claude aren't loading or throw errors. This guide covers file format support, size limits, and browser settings—everything you need to fix file upload problems.
Build a PDF Analysis and Summarization App with Claude API — Vision plus Extended Thinking
Learn how to build a PDF analysis and summarization application using Claude API's Vision capabilities and Extended Thinking, with step-by-step Python implementation.
Claude Files API Guide — Upload Once, Reference Anywhere in Your API Calls
Learn how to use the Claude Files API to upload PDFs, images, and text once and reference them across calls. Includes Python and TypeScript examples, a production-grade retry helper, real token cost estimates, and hard-won operational tips.
Multimodal Input Guide — Working with Images and PDFs in the Claude API
How to send images and PDFs to the Claude API, when to reach for the Files API, and the cost and speed lessons you only learn by running it in production — with real measurements.