Goodbye Opus, Hello Fable
Anthropic shipped Claude Fable 5 and Mythos 5: same model, two names, one safeguard layer apart. What the new frontier model means for running agents in production.
Blog
17 posts
Context architecture beats documentation dumps
Dumping the whole corpus into an AI agent makes it worse, not better. The fix is architectural: each task loads a curated slice, not everything you have. Here is the method, and the same move at three different layers: specs, sensor data…
The Orange Pi That Maintains Itself
A small ARM box that started as a local LLM experiment and ended up a self-governing node: private retrieval, a resident agent under a written constitution, a code-enforced safety fence, and a nightly job where it audits itself and files…
An orchestration mode is only as good as its backlog
Anthropic published a guide on building a session-level orchestration mode. I built it two ways, on the CLI and on the API, and then hit the part the guide does not cover: an orchestrator that fans out is useless without a backlog of rea…
Wiring Garmin Into My Marathon Coach: A Live Data Integration Without an Official API
How I replaced manual CSV exports with a live Garmin data feed for my AI marathon coach: a scheduled unofficial-API poller, resilient session handling, and the design calls that keep training and recovery data fresh and trustworthy.
A Boring Design Let Me Run a Black Swan on a Tuesday
Two posts ago I bet that keeping my portfolio reviewer's engine deterministic and auditable was worth it. This is where that bet paid off: because the engine is replayable, I could run a simulated market crash through the real production…
The caskeycoding.com tech stack at a glance
A high-level tour of the technologies running this site: Next.js on CloudFront, Python Lambdas behind API Gateway, DynamoDB plus S3, Anthropic's API with a Bedrock fallback, and AWS CDK wiring it together.
Building a Personal Finance Reviewer: What Survived the Rewrite
A personal portfolio reviewer where the scoring is deterministic and the AI only narrates. The architecture that held up after I had to rewrite the model it was built on, and why that boundary is the whole point.
When the Spec Was Wrong: Rewriting a Shipped Decision
Two weeks after I shipped a post about a scoring engine I'd built, I rewrote the spec it was based on. Here's what I learned, and why I had an AI agent do the literature review.
One week of SDD in production: the numbers
The previous two posts made claims. Here is what a week of the workflow looks like as a data trail, PRs, deploys, CI runs, specs merged, pulled from GitHub.
SDD isn't about managing AI agents, it's about managing context
Spec-driven development reads like a methodology for controlling AI agents. It isn't. It's a methodology for managing context across stateless sessions. The spec is the persistent memory.
Specs in, deploys out, no keyboard
Two production sites, a blog, and two personal AI projects, shipped this week from a phone. The chain is voice dictation into Perplexity Computer, a spec, then Claude Code on the web. The interaction model is the story.
Building an AI Marathon Coach: Deterministic Rules, LLM Narratives, and the 2026 NYC Marathon
How I built a personal AI coaching system for marathon training, layering deterministic guardrails over an LLM narrative engine, ingesting Garmin FIT files, and designing for my own injury history.
Designing Safety Guardrails for Distributed Workflow Orchestration
Patterns for pre-execution safety checks, parallel validation, opt-out design, and extensible guardrail architecture on workflow platforms.
Spec-Driven Development and the Folder Architecture That Makes It Work
Why spec-driven development and structured folder architecture are the missing infrastructure for AI-assisted engineering: methodology, common mistakes, and where to start.
Book Review: Enterprise Vibe Coding Playbook, Building Real Software with AI
A practitioner's review of Doug Kerwin's Enterprise Vibe Coding Playbook, why AI as a thinking partner, not a replacement, is the framework enterprise engineering teams need.
Welcome: Building Platforms for Scale
An introduction to the blog, reflections on infrastructure monitoring, platform leadership, and building systems that empower organizations to innovate safely at scale.