All Articles
Forecasting Claude API token costs with ±10% accuracy from the first three days
A practical EWMA + seasonality decomposition model that forecasts month-end Claude API costs from only the first three days of token usage, with three-tier automated guardrails for prompt caching, model routing, and rate limiting.
Resolving Tool Name Collisions When Bundling Multiple MCP Servers in the Claude Agent SDK
When the GitHub MCP and Linear MCP both expose create_issue, Sonnet 4.6 cannot tell them apart. This article walks through the structure of MCP tool name collisions, a TypeScript reconciler implementation, and the production failure modes I hit running six sites at once.
Compressing Tool Results in Claude Agents — Aggregating Large Responses Without Bloating Context
When a database returns 8,000 rows, a scrape returns 200KB of HTML, or a file read returns several megabytes, dropping the raw payload into your Claude tool result wrecks both cost and quality. This guide presents a three-layer compression architecture — schema projection, summarization, and reference handles — with TypeScript examples from a production agent pipeline.
Hierarchical Chat History Summarization with Claude API: A 3-Tier Design That Cut Tokens by 70%
Working TypeScript design for compressing long in-app chat histories into three tiers — recent turns kept verbatim, mid-range episodes summarized with Haiku 4.5, and long-range memory distilled to JSON by Sonnet 4.6. Includes seven weeks of production data showing input tokens down 70% and monthly API cost down from $480 to $145.
Installing Safety Valves in Claude Agents: A Three-Layer Kill-Switch Design for Solo Operators
A design record from a real production incident — three hours of runaway retries that cost $32 — that led me to rebuild every Claude agent with a three-layer kill switch: in-process guards, platform-level kill flags on Cloudflare KV, and an observer worker that catches the warning signs within three minutes. Working TypeScript and operational metrics included.
Claude SDK Tool Calls Failing with InputValidationError: How to Handle Deferred Tools
When Claude Code SDK or Cowork tools throw InputValidationError, the root cause is usually deferred tool schemas. This guide explains why it happens and how to fix it with ToolSearch.
Debugging Claude API Tool Use Schema Errors: 3 Patterns I've Hit and How to Fix Them
A practical guide to diagnosing Claude API Tool Use errors—from schema definition mistakes to invalid_tool_use blocks and Claude ignoring your tools entirely. Based on real implementation experience.
Automating Multilingual App Review Replies with Claude API — Real Lessons from 50M Downloads
An indie developer behind 50M+ download apps shares the full implementation of Claude API-powered multilingual review reply automation — including App Store's undocumented 8-second rule, session limits, and the three traps that can get you banned.
Automating Wallpaper Classification with Claude Vision API — Real Lessons from a 50M Download App
A firsthand account of automating wallpaper category classification using Claude Vision API in production. Honest results on accuracy, costs, and pitfalls encountered.
Cutting Claude API Costs in Half with Messages Batches API — Design Patterns from an Indie Developer
How to reduce Claude API costs by up to 50% using the Messages Batches API. Includes async design patterns, real cost calculations, and production-ready error handling from an indie developer who runs four AI blogs on autopilot.
6 Traps I Hit Building In-App AI Chat with Claude API — A Record of Getting to Production
Six real design mistakes I encountered shipping Claude API in-app chat to production — covering context management, streaming error detection, guardrails, session persistence, model versioning, and cost monitoring. Includes working TypeScript code.
Design Decisions Every Indie Developer Faces When Integrating Claude API into Mobile Apps
A practical guide to the design decisions that indie mobile developers face when integrating Claude API — covering model selection, async UX patterns, context management, offline resilience, and cost control, drawn from 10+ years of personal app development experience.