Inserting Approval Gates Into Your Agents — A Production Design for Human-in-the-Loop With the Claude API
Once you put an agent in production, the requirement 'please get a human to approve just this specific decision' appears within days. This guide walks through the design patterns for retrofitting approval gates and handling suspend/resume correctly, with working code.
Intelligent Model Routing with Claude API — Auto-Selecting Sonnet 4.6 and Haiku 4.5 for Optimal Cost and Quality
Build an intelligent routing layer that automatically selects between Claude Sonnet 4.6 and Haiku 4.5 based on request complexity. Covers classifier design, circuit breakers, fallback chains, and cost monitoring for production deployments.
An Implementation Notebook for Shipping Android/Kotlin Apps to Google Play with Claude Code
A production notebook from years of running an indie Android app business. Compose × Hilt × Room design calls, ProGuard crash triage, and a 14-item pre-release checklist that goes in front of every Google Play AAB upload.
Running Claude Sonnet 4.6 in Production While Scouting the Move to Sonnet 5
Claude Sonnet 4.6 shipped February 17, 2026 and is now legacy, with retirement no sooner than February 17, 2027. Real prices against Opus 4.6, the 1M context, thinking, Computer Use, and the five places a Sonnet 5 migration returns 400.
Claude API Messages Batches: Cutting Production Costs by Up to 50% with Async Processing
Field notes from running the Claude API Messages Batches API in production. Polling design, composite custom_id keys, the 29-day window that starts at created_at rather than completion, and the cost numbers recomputed from current published prices.
Claude API Production Resilience Patterns — Model Routing, Circuit Breakers, and Fallback Strategies for Indie Teams
Production resilience patterns for Claude API: circuit breakers, intelligent model routing, fallback chains, exponential backoff with jitter, and disaster recovery — with TypeScript implementations and operational notes from an indie developer.
Building LLM Evaluation Pipelines with Claude API — Claude-as-Judge, Prompt A/B Testing, and Quality Scoring Patterns
Designing and implementing LLM evaluation pipelines on the Claude API — Claude-as-Judge, prompt A/B testing, quality scoring, and regression testing for production applications.
Coalescing Concurrent Claude API Calls: Single-Flight Against Duplicate Inference and Cache Stampede
A design for collapsing identical prompts that fire at the same instant into a single upstream Claude call, using single-flight (request coalescing). In-process and distributed implementations, jittered retries, and negative caching, with measured results.
Designing Around Claude API 413 request too large — Preflight Sizing and Splitting
Pack too much text, images, and tool_result into one request and Claude API rejects it with 413 request too large. Here is a code-backed design for measuring request bytes before you send, telling the two kinds of 413 apart, and splitting requests without breaking them.
Is the Draft That Passed the Gate the Same One You Published?
In unattended pipelines, the file your quality gate inspected and the file you actually publish can quietly diverge. Here is a digest-bound gate receipt design, with working code and measured results from 180 days of running it.
When Claude API Suddenly Starts Returning 429 in Production — Field Notes on Measuring Rate-Limit Headroom from Headers and Throttling Before You Run Dry
Scrambling to add retries after a 429 is always a step behind. Claude API writes how much you have left into every response header. These are field notes on measuring that headroom continuously and throttling yourself before it runs out.
How Many Concurrent Claude API Requests Can You Actually Hold? Sizing Production Infrastructure with Little's Law and Measured Memory
Concurrency, queue depth, and memory are numbers you can derive, not guess. A working method for sizing Claude API production deployments with Little's Law, a memory probe, and a 30-minute load check — learned the hard way from an OOM crash.