TDD

Prologue: 1,754 Perfect Green Lights The team watched the test panel late on the night Aristotle v1.6.0 shipped. Green indicators lit up like dominoes. Python side: 1,166 assertions. TypeScript side: 588 checks. Total: 1,754 automated checks. All green. In code terms, that’s like having cameras and infrared sensors on every wall. A fly couldn’t sneak through without setting off alarms. The team leaned back. The system looked like an iron fortress. ...

TL;DR: Five constraints shaped the Watchdog-Intervention Bridge’s cross-language architecture. Watchdog must intercept LLM tool calls synchronously, so it runs in TypeScript. Intervention must reuse the existing reflection engine and rule system, so it stays in Python. The Bridge adds zero new infrastructure, so it uses subprocess. Communication can’t block every tool call, so batching replaces real-time streaming. MCP’s subprocess model already handles failure, so cross-language risk stays contained. Each decision was the least bad option under the circumstances. ...

TL;DR: Aristotle v1.6.0 introduces the Watchdog-Intervention Bridge, shifting from “reflect after the fact” to “intercept in real time.” A TypeScript watchdog detects 21 signal types before and after tool calls. A Python intervention layer handles 13 violation types, connected via a subprocess bridge. MCP tools expand from 10 stubs to 25 full implementations. Two known bugs remain. Open source on GitHub, MIT license. A Hypothesis Overturned From v1.0 to v1.5, Aristotle answered one question: when AI makes a mistake, how do you make it remember and not repeat it? ...

Series: Breaking to Build: TDD Process Iterations (Post 3) Post 1: What a Failed Experiment Got Right · Post 2: Using the Method to Improve the Method TL;DR: Phase 6 already does diagnostics at the integration level — drilling into each bug’s root cause. What it doesn’t do: cross-defect pattern scanning, component gap checking, execution order analysis. Those belong to Phase 7. In small systems, Phase 7 catches a few more bugs. As the system grows, those same three tasks produce something different — building test infrastructure, hardening CI rules, driving architectural evolution. Phase 7 doesn’t make architecture decisions. But it provides the scarcest input for those decisions: evidence-based problem localization. ...

Series: Breaking to Build: TDD Process Iterations (Post 2 of 3) Previous: What a Failed Experiment Got Right · Next: The Invisible Blank Layer TL;DR: The TDD Pipeline taught “give principles, not steps” — but it had grown into a step-driven tool itself. I stripped the operational steps from Phases 1 through 5, keeping only principles, risk hints, and counterexamples. The model independently derived the steps I had deleted. Output quality held. The reason: Phases 1 through 5 are creative phases that need room to diverge. Removing the fixed track actually helped. The same strategy failed on Phase 6 — next post explains why. ...

Series: Breaking to Build: TDD Process Iterations (first post) TL;DR: I refined Phase 6 (pre-release testing) of the TDD Pipeline from step-driven to principle-driven. The goal was better output. I didn’t get it — the refined version was worse at drilling into individual bugs and building evidence chains. But comparing the two outputs revealed dimensional differences. The refined version was better at component gap checking and cross-bug pattern scanning. Those differences pointed to a judgment call: Phase 6 doesn’t need refining. It needs a layer on top of it. That layer later became Phase 7. ...

TL;DR: Before-and-after comparison of the upgraded Why Articulation template, plus three transferable lessons: give principles not examples, lock critical steps with mandatory tone, and trust the model’s self-organization. Experiment limitations included. Series: Why Make AI Articulate Why Before Acting (Article 3) Previous: A 4-Variable A/B Test — Why Positive Examples Harm Prompt Performance Recap Article 1 started from Anthropic’s alignment research: teaching a model why rather than what cut misalignment from 22% to 3% (about 7×), and achieved equivalent results with 1/28 of the data [1]. I adapted this into Why Articulation: a mechanism that forces AI to explain purpose, risks, and approach before writing any code. ...

TL;DR: A 4-variable A/B test on Why Articulation — structure, tone, position, and examples. Positive examples made output worse. The model imitated instead of reasoning. Open-ended prompts improved quality directionally and cut tokens by 33%. Series: Why Make AI Articulate Why Before Acting (Article 2) Previous: From Anthropic’s Alignment Research to a Prompt Design Insight Where We Left Off Anthropic’s alignment research [1] landed on a sharp insight: teaching a model why beats telling it what. I took that idea and built Why Articulation into my TDD Pipeline: a mechanism that forces the model to explain its understanding before it writes any code. Early results looked good. ...

TL;DR: Anthropic’s alignment research shows that teaching a model why works better than teaching it what — misalignment dropped from 22% to 3%. This post breaks down four experiments and distills three lessons you can use in prompt design. I ran an A/B test comparing two prompt strategies. One group got positive examples: “do it like this.” The other got no examples. Instead, the AI had to explain why a choice was correct before acting on it. ...

TL;DR: Before releasing Aristotle v1.1, I found 18 bugs. Unit tests caught four (22%). The other 14 lived at the integration layer — component wiring, config propagation, process startup seams. Root cause analysis revealed six patterns: path/environment mismatch (5), registration omission (3), startup hang (2), silent failure (2), test-production path divergence (2), integration seam errors (4). The root cause isn’t harder problems — it’s AI bypassing the defenses that experience built. Implementation and review rhythms decouple, code appearance misleads quality judgment, and integration shifts from an explicit action to an implicit assumption. Includes an eight-dimension integration checklist and a 16-type bug roadmap at the end. ...