Posts
Write the Rule, Not the Story
When a plan dies, its durable knowledge moves into a skill — and it keeps arriving as a changelog. A 59-section audit found only 44% met the bar, and the fix was a one-paragraph standard: state what a session must do now, never how the decision was reached.
Four Answers to One Question
A codebase answered 'is this precipitation probability worth showing?' four different ways in four places - the fix was one pure chokepoint function, a rule that keeps it singular, and a sweep that proved it complete.
Fix Only Observed Harm
A six-line gate for agents and reviewers: no fix or guard gets built without named evidence, won't-fix with a revive trigger is a real outcome, and a guard's own counter can authorize its deletion.
The Body Runs Every Frame
A choppy watch drag traced to loop-invariant computed properties re-evaluated per ForEach element per body pass - the hoisting rules learned fixing it, and why a green, twice-reviewed 51-file fix was closed and re-landed in slices.
‘Nothing to Change’ Is a Valid Review Verdict
The sequel to adversarial review rounds: after months of running them, the failure mode wasn't bad reviews - it was auto-acting on them. The fix is a user checkpoint and one sentence: the digest is a filter, not a to-do list.
Port the Ergonomics, Not the Library
When bringing snapshot testing from a Ruby codebase to Swift Testing, the thing worth porting turned out to be three ergonomic properties - drop-in assertion, automatic naming, one-flag update - not a package and not a dependency.
Your Best Model Is the Wrong One to Delegate To
Route delegated work by kind, not capability: judgment stays on the frontier session model, bounded briefs go to a pinned mid-tier model with bounded effort, and bulk work goes to the cheapest tier.
Sync Only What the Watch Reads: An Allowlist Inversion
Auditing every settings key in a phone-to-watch sync payload, inverting a denylist into an opt-in allowlist, and defusing a protocol where a missing key gave away the paid app for free.
Reserving the Top of the Scale: A Hazard Band for Auto-Ranked Cards
A ranking pattern that reserves the top of a 0-1 salience scale for externally-anchored severity, caps editorial signals below the floor, and ships ordering from the server.
Plans Are Disposable, Skills Are Durable
A full lifecycle policy for agent-facing docs: how plans get written to a handoff-ready standard, when they get deleted, what the index is allowed to hold, and how an agent decides that the correct next action is nothing.
Deleting the Workarounds: Fixing Every Digital Crown Bug at Once
Seven months of Apple Watch crown-scrolling workarounds turned out to be the bug. Two structural root causes, one deletion PR, and how to hand-roll scroll momentum on watchOS.
An Agent Fan-Out Pipeline with a Hard Isolation Contract
Running dozens of coding agents in parallel doesn't need a smarter reviewer. It needs a brief schema, central wiring done first, a mechanical verifier, and an isolation contract that makes throwaway-quality output safe to merge.
Mining the Support Inbox for Bugs Your Crash Reporter Can’t See
A decade of support email, parsed into a local SQLite corpus and classified by agents, became a second telemetry channel - and found a silent subscription bug that produced zero crash reports.
Never Trust the Vendor’s Language List: Probing 10 APIs in 27 Languages
We live-probed every upstream data source in all 27 supported languages and found four distinct failure modes hiding behind vendor documentation.
Measuring Strings Before You Translate Them: Fixing Truncation in 22 Languages Without an App Update
Standalone Swift validators that render every localized string at its real font and compare it to a computed layout budget - turning UI truncation into a committed work-list, and then into a server-side content fix.
The Vendor Sent Gzip Without a Content-Encoding Header — and the CDN Cached It
A vendor returned raw gzip bytes in a 200 with no Content-Encoding header, CloudFront cached it for 24 hours, and 12.7k errors a day were invisible in CDN logs. The fix sniffs magic bytes at one transport chokepoint — with a hard cap on inflation, because Falcon shares one reactor.
The Agent-Doc Audit: Deleting the Fiction Your AI Has Been Believing
A four-tier audit of every agent-facing doc across three repos. Wrong content is worse than no content, because agents act on it - and deleting a quarter to a third of the corpus made the agents better.
Adversarial Review Rounds: Fresh-Context Reviewers Catch What Informed Review Can’t
Before the merge call, dispatch two or more read-only reviewer agents with deliberately different lenses and no session context - then adjudicate their findings yourself.
Server-Controlled Promo System with Offer Codes
A flexible promo architecture that uses App Store offer codes instead of introductory offers, with server-side activation and CLI-based offer management.
StoreKit 2 Implementation Guide
A complete production-ready StoreKit 2 implementation with transaction verification, real-time monitoring, persistence, and paywall UI patterns.
Research First: Using Claude Web Before Claude Code
A workflow for better decisions: deep research on Claude.ai, then implementation handoff to Claude Code with full codebase context.
Multi-Source API Adapter Pattern in Ruby
A pattern for normalizing multiple external APIs into a unified interface with automatic unit conversion.
Debugging Dependencies: Research Before Workarounds
Two patterns for working with third-party code: investigate source before guessing, and research upstream before patching.
Privacy-First Crash Reporting
A philosophy for minimal crash reporting: collect only stack traces, audit SDK updates for hidden telemetry, and verify nothing extra ships.
AI Agent Permissions: Trust but Verify
A tiered permission system for Claude Code and Codex that balances autonomy with safety.
APNS Background Refresh: Privacy Through Simplicity
How Hello Weather uses silent push notifications to refresh weather data without storing customer locations on the server.
Falcon and Ruby Async: Why Ruby Works for I/O-Bound Services
Using Falcon and async-http for fiber-based concurrency, achieving 87% latency reduction without leaving Ruby.
CloudFront Logging: Time-Boxed Investigations
Running targeted logging campaigns to investigate timeout behavior and tune per-source timeouts.
CloudFront as an Infinite Cache
Using CloudFront distributions as a caching layer between your app and upstream data providers, with careful cache key design.
Heroku Capacity: Scaling for Traffic Spikes
Dyno scaling decisions backed by data, not guesswork, with guardrails that prevent both over-provisioning and capacity crunches.
App Store Pricing: 175 Territories, One CLI
Managing App Store subscription pricing across 175 territories with PPP adjustments, offer codes, and a CLI that prevents mistakes.
Planning Skill: Living Documents, Not Project Management
A lightweight approach to planning with Claude: create plans, implement them, remove them. No project management software required.
Mono-Repo Architecture: One Rails App, Multiple Products
Using host-based routing to serve Hello Weather and WeatherMachine from a single Rails application.
Skills and Scripts: A Pattern for LLM Workflows
How pairing SKILL.md files with bin/ scripts creates powerful, reusable LLM workflows.
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