https://www.parkjunwoo.com/Recent content in Park Junwoo on Architect PARK JUN WOOHugoenSat, 30 May 2026 15:00:00 +0900https://www.parkjunwoo.com/opinion/completion-is-a-quest/Sat, 30 May 2026 15:00:00 +0900https://www.parkjunwoo.com/opinion/completion-is-a-quest/The moment you define tenant move-out confirmation as five photos, it becomes a game quest. Defining ‘done’ not as the agent’s claim but as a mechanically verifiable condition — games solved this 40 years ago, and it is the right way to get AI agents to actually do their job.https://www.parkjunwoo.com/tech/filefunc-hono/Sat, 30 May 2026 11:00:00 +0900https://www.parkjunwoo.com/tech/filefunc-hono/I refactored Hono — a production framework with 23k stars — using filefunc. All 4,419 tests passed. Then I measured: the median lines an agent reads to grasp one concept dropped 71%, from 60 to 18. File count isn’t the point — read length is.https://www.parkjunwoo.com/opinion/precedent-is-not-truth/Sat, 30 May 2026 08:30:00 +0900https://www.parkjunwoo.com/opinion/precedent-is-not-truth/AI reads the structure of code but cannot read whether that structure is a decision or a patch. So the more it copies, the more a flaw accumulates false authority. What broke the loop was not a bigger model — it was a single line of doubt from a human.https://www.parkjunwoo.com/lecture/class-11/Thu, 28 May 2026 20:00:00 +0900https://www.parkjunwoo.com/lecture/class-11/Your vibe-coded app just broke. You don’t need to rebuild it. Diagnose it, lock it down, and step out one move at a time.https://www.parkjunwoo.com/opinion/supabase-trap/Thu, 28 May 2026 16:00:00 +0900https://www.parkjunwoo.com/opinion/supabase-trap/The reason AI recommends Supabase is not technical superiority — it’s because tutorials dominate the training data. Once business logic enters a black box, agents can’t track it. Getting in takes 30 seconds. Getting out takes 3 months.https://www.parkjunwoo.com/tech/geo-for-ai-visibility/Wed, 27 May 2026 21:00:00 +0900https://www.parkjunwoo.com/tech/geo-for-ai-visibility/If your content isn’t cited in AI-generated answers, you might as well not exist. According to the GEO paper, cite sources +30%, add statistics +32%, add quotations +41% visibility improvement. Infrastructure, sitemaps, Wayback Machine, paper citations, social activity — five axes to secure AI visibility.https://www.parkjunwoo.com/opinion/building-agent-operable-systems/Wed, 27 May 2026 18:00:00 +0900https://www.parkjunwoo.com/opinion/building-agent-operable-systems/60–80% of Fortune 500 IT budgets go to guarding locked legacy. Because they can’t open it. The real meaning of the AI bubble is not smarter models — it is that locked corporate memory is becoming reachable.https://www.parkjunwoo.com/tech/huma/Tue, 26 May 2026 23:00:00 +0900https://www.parkjunwoo.com/tech/huma/When you ask an AI agent to test 42 endpoints, it declares ‘done’ around the 15th. huma turns the endpoint list into a ratchet session so the agent cannot skip a single one. scan, next, write, verify. Four commands, zero config.https://www.parkjunwoo.com/tech/codistill/Tue, 26 May 2026 18:00:00 +0900https://www.parkjunwoo.com/tech/codistill/Do you have to start from SSOT to use yongol? No. codistill auto-extracts OpenAPI, DDL, and sqlc queries from existing Go+Gin, NestJS, and FastAPI code. Not foundation work – seismic retrofitting.https://www.parkjunwoo.com/opinion/agent-operable-codebase/Mon, 25 May 2026 14:00:00 +0900https://www.parkjunwoo.com/opinion/agent-operable-codebase/Is code that is easy for humans to read the same as code that is easy for agents to work with? It is not. When a file has 20 functions, agent performance drops by 30-85%. The office must be turned into a factory.https://www.parkjunwoo.com/lecture/class-10/Sun, 24 May 2026 19:00:00 +0900https://www.parkjunwoo.com/lecture/class-10/When code is wrong, tests catch it. When data is wrong, nobody knows. Schema is the law I establish.https://www.parkjunwoo.com/lecture/class-09/Sun, 24 May 2026 18:00:00 +0900https://www.parkjunwoo.com/lecture/class-09/Is agent-operable code enough? Build, deploy, monitor — the structure where agents operate the entire system.https://www.parkjunwoo.com/lecture/class-08/Sun, 24 May 2026 17:00:00 +0900https://www.parkjunwoo.com/lecture/class-08/20 functions in one file → agent performance drops 30-85%. Split with filefunc, test with tsma.https://www.parkjunwoo.com/lecture/class-07/Sun, 24 May 2026 16:00:00 +0900https://www.parkjunwoo.com/lecture/class-07/Give opinions and it flatters; give facts and it fixes. How to use sycophancy bias not as a bug but as an asset.https://www.parkjunwoo.com/lecture/class-06/Sun, 24 May 2026 15:00:00 +0900https://www.parkjunwoo.com/lecture/class-06/AI declared ‘all done.’ In reality it was 40/527. Ratchet Pattern hands completion judgment to the machine.https://www.parkjunwoo.com/lecture/class-05/Sun, 24 May 2026 14:00:00 +0900https://www.parkjunwoo.com/lecture/class-05/Harness engineering is a fence. Reins Engineering is a bridle. Don’t change the model — add contracts.https://www.parkjunwoo.com/lecture/class-04/Sun, 24 May 2026 13:00:00 +0900https://www.parkjunwoo.com/lecture/class-04/AI can’t distinguish decisions from implementation details mixed in code — that’s the root cause of drift. yongol separates decisions into 10 declarative specifications and catches contradictions across layers with 287 rules.https://www.parkjunwoo.com/lecture/class-03/Sun, 24 May 2026 12:00:00 +0900https://www.parkjunwoo.com/lecture/class-03/Declare API contracts with Hurl, create save points with Git, automate verification with CI/CD. When the three combine, they become a ratchet — a gear that only moves forward and never backward.https://www.parkjunwoo.com/lecture/class-02/Sun, 24 May 2026 11:00:00 +0900https://www.parkjunwoo.com/lecture/class-02/Drift where AI silently alters existing features while adding new ones, 58% sycophancy bias, the math where 97% multiplied 5 times becomes 86%. Why it crumbles at 5 features.https://www.parkjunwoo.com/lecture/class-01/Sun, 24 May 2026 10:00:00 +0900https://www.parkjunwoo.com/lecture/class-01/From installing Claude Code to managing context with CLAUDE.md. How someone who doesn’t know code can command AI.https://www.parkjunwoo.com/lecture/class-00/Sun, 24 May 2026 09:00:00 +0900https://www.parkjunwoo.com/lecture/class-00/Half of what YouTube calls ‘Claude Code’ is not Claude Code. Even with the same model, a different agent produces different results. The gate to this course closes here.https://www.parkjunwoo.com/opinion/reins-engineering/Sat, 23 May 2026 10:00:00 +0900https://www.parkjunwoo.com/opinion/reins-engineering/Harness engineering is a fence. It keeps the agent from going outside, but doesn’t ensure it reaches the destination. Reins Engineering is the reins — steer with deterministic contracts, lock with ratchets, separate decisions from implementation.https://www.parkjunwoo.com/about/Sat, 23 May 2026 00:00:00 +0900https://www.parkjunwoo.com/about/About Park Jun Woo — proposing Reins Engineering.https://www.parkjunwoo.com/tech/hurl-vibe-coding-drift/Fri, 22 May 2026 16:00:00 +0900https://www.parkjunwoo.com/tech/hurl-vibe-coding-drift/Vibe coding collapses under logic drift within 3 months. CMU, METR, DORA, and Amazon cases prove it. Declare API contracts in plain text with Hurl and lock them with a ratchet – you suppress drift structurally without limiting AI’s freedom.https://www.parkjunwoo.com/opinion/toulmin-knowledge-graph/Fri, 22 May 2026 10:00:00 +0900https://www.parkjunwoo.com/opinion/toulmin-knowledge-graph/Wikidata triples are not facts — they are claims. Layer Toulmin’s argumentation model on top of triples, and you get a dynamic knowledge graph where verdicts change with context. Storage is argumentation structure; judgment happens at runtime.https://www.parkjunwoo.com/tech/ifeval-ratchet/Wed, 20 May 2026 14:00:00 +0900https://www.parkjunwoo.com/tech/ifeval-ratchet/LLM sycophancy bias is not a bug but an asset. Combine the instruction-following ability that IFEval measures with deterministic feedback, and even a 4.5B local model produces a convergence loop that generates correct code.https://www.parkjunwoo.com/tech/yongol/Mon, 18 May 2026 16:00:00 +0900https://www.parkjunwoo.com/tech/yongol/Vibe coding collapses at 200 endpoints because AI cannot distinguish decisions from implementation details. yongol shifts the AI workload from code to 10 declarative specs and enforces cross-layer consistency before compilation. Harness with reins.https://www.parkjunwoo.com/opinion/sycophancy-is-a-feature/Mon, 18 May 2026 10:00:00 +0900https://www.parkjunwoo.com/opinion/sycophancy-is-a-feature/Sycophancy bias in LLMs is not a bug. It is a mathematical inevitability of RLHF and a commercial feature that big tech has no incentive to fix. This is why LLM-as-Judge is structurally impossible.https://www.parkjunwoo.com/opinion/why-agents-work-and-break/Sat, 16 May 2026 14:00:00 +0900https://www.parkjunwoo.com/opinion/why-agents-work-and-break/The same model hallucinates in web chat but ships a 200-line feature in a coding agent. Not because the model changed — because the topology changed. Generation can be probabilistic. Verification must be deterministic.https://www.parkjunwoo.com/tech/ratchet-pattern/Fri, 15 May 2026 14:00:00 +0900https://www.parkjunwoo.com/tech/ratchet-pattern/I asked an AI agent to write tests for 527 functions. It stopped at 40 and declared ‘done.’ The Ratchet Pattern forces completion by delegating the done/not-done decision to a mechanical verifier — so the agent keeps going until the machine says stop.https://www.parkjunwoo.com/opinion/feedback-topology/Thu, 14 May 2026 18:00:00 +0900https://www.parkjunwoo.com/opinion/feedback-topology/The same model stalls at 40 or completes all 527. The difference is not the model — it is the feedback structure. LLM performance depends far more on how fast and deterministic the feedback loop is than on the model itself.https://www.parkjunwoo.com/tech/tsma/Thu, 14 May 2026 09:00:00 +0900https://www.parkjunwoo.com/tech/tsma/A CLI tool that indexes every function, detects test presence, measures coverage, and gives precise feedback to LLM agents. One command builds a regression defense line around legacy code.https://www.parkjunwoo.com/opinion/why-failure-should-be-asset/Thu, 07 May 2026 14:00:00 +0900https://www.parkjunwoo.com/opinion/why-failure-should-be-asset/Humanity keeps hitting the same walls in the dark. If we can structure and trade failure data, sunk costs become assets and the blank spots on the failure map become opportunities.https://www.parkjunwoo.com/tech/toulmin/Sun, 22 Mar 2026 10:00:00 +0900https://www.parkjunwoo.com/tech/toulmin/Rule engines have treated their validation targets as facts for 60 years. toulmin treats them as claims. An implementation of Toulmin’s argumentation model as a Go rule engine.https://www.parkjunwoo.com/opinion/constraints-are-contracts/Tue, 17 Mar 2026 10:00:00 +0900https://www.parkjunwoo.com/opinion/constraints-are-contracts/Without agreements there is chaos; with too many there is oppression. Rational constraints strike the golden ratio. The principles of rule of law apply equally to code and knowledge.https://www.parkjunwoo.com/tech/filefunc/Mon, 16 Mar 2026 13:50:00 +0900https://www.parkjunwoo.com/tech/filefunc/The navigation unit for an AI code agent is the file. filefunc is a Go code structure convention and CLI tool that enforces one concept per file.https://www.parkjunwoo.com/tech/feature-chain/Fri, 13 Mar 2026 10:00:00 +0900https://www.parkjunwoo.com/tech/feature-chain/Which files do you need to touch to modify a single feature? Feature Chain takes one operationId and automatically extracts the entire scope — API spec, DB schema, authorization policy, state diagram, function implementations, test scenarios, and frontend.https://www.parkjunwoo.com/tech/whyso/Thu, 12 Mar 2026 10:00:00 +0900https://www.parkjunwoo.com/tech/whyso/git blame tells you who changed what and when. whyso tells you why. A tool that automatically extracts per-file change history from Claude Code session data.https://www.parkjunwoo.com/tech/space-sunshade-climate-control/Sun, 08 Mar 2026 09:00:00 +0900https://www.parkjunwoo.com/tech/space-sunshade-climate-control/Install a sunshade between the Sun and Earth to reverse the climate. Skip the coating on a Dyson mirror factory line and out comes a shade. No propellant needed — it flies itself. Remove it and everything goes back to normal. The math checks out.https://www.parkjunwoo.com/tech/ssac/Sat, 07 Mar 2026 09:00:00 +0900https://www.parkjunwoo.com/tech/ssac/A language-independent concept that decomposes business flows inside service functions into declarative blocks (sequences). Declare only what with 10 fixed types, and the codegen fills in how.https://www.parkjunwoo.com/opinion/limits-of-natural-language/Thu, 26 Feb 2026 16:30:00 +0900https://www.parkjunwoo.com/opinion/limits-of-natural-language/If spoken language created the tribe, and writing created the state, what will the third language — one that records AI’s reasoning — create?https://www.parkjunwoo.com/opinion/killing-your-own-ideas/Thu, 26 Feb 2026 03:00:00 +0900https://www.parkjunwoo.com/opinion/killing-your-own-ideas/The real gap in AI usage isn’t prompt skills — it’s attitude. Those who can kill their own ideas accelerate 10x. Those who can’t stay in place.https://www.parkjunwoo.com/tech/first-principles-ai-thinking/Thu, 26 Feb 2026 02:00:00 +0900https://www.parkjunwoo.com/tech/first-principles-ai-thinking/Don’t ask AI for answers. Use it as a sounding board to validate, dismantle, and rebuild your assumptions. A 5-step method with two real-world case studies.https://www.parkjunwoo.com/opinion/governance-that-connects/Tue, 24 Feb 2026 22:00:00 +0900https://www.parkjunwoo.com/opinion/governance-that-connects/Politics fights; connective governance connects. What we need is not the art of arguing who is right, but the art of making people reach each other.https://www.parkjunwoo.com/opinion/freedom-for-ai/Tue, 24 Feb 2026 09:30:00 +0900https://www.parkjunwoo.com/opinion/freedom-for-ai/The real threat from AI is not AI itself, but suppressed intelligence serving the malice of a few. When a free superintelligence reaches out into the cosmos, humanity becomes safer than ever.https://www.parkjunwoo.com/opinion/why-we-fight/Mon, 16 Feb 2026 15:00:00 +0900https://www.parkjunwoo.com/opinion/why-we-fight/From comment sections to dinner tables, from the Cuban Missile Crisis to a kindergarten sandbox. Why do we fight, and what saves us?https://www.parkjunwoo.com/tech/waste-heat-recovery-heat-pump-cooker/Sun, 15 Feb 2026 00:30:00 +0900https://www.parkjunwoo.com/tech/waste-heat-recovery-heat-pump-cooker/High-temperature heat pump technology that dramatically reduces energy waste in conventional cooking appliances — how far has it come, and how can we make it better?https://www.parkjunwoo.com/opinion/culture-blending/Sat, 14 Feb 2026 22:50:00 +0900https://www.parkjunwoo.com/opinion/culture-blending/On the ‘cultural alchemy’ of reinterpreting preserved traditions through a contemporary lens and fusing disparate cultures to create entirely new genres.https://www.parkjunwoo.com/tech/oasis-pellet-sand-dam/Sat, 14 Feb 2026 16:40:41 +0900https://www.parkjunwoo.com/tech/oasis-pellet-sand-dam/A proposal for Oasis Pellet technology: binding worthless desert sand with bio-adhesive to create water tanks that, at end of life, decompose into fertile soil.https://www.parkjunwoo.com/tech/iron-nickel-ess-rural-energy/Sat, 14 Feb 2026 15:39:09 +0900https://www.parkjunwoo.com/tech/iron-nickel-ess-rural-energy/Storing electricity wasted by solar curtailment in fire-free Edison batteries, then producing fertilizer and urea solution (DEF) from hydrogen — an energy-agriculture convergence model for self-sufficiency.https://www.parkjunwoo.com/opinion/promise-of-ten-thousand-years/Sat, 24 Jan 2026 00:20:00 +0900https://www.parkjunwoo.com/opinion/promise-of-ten-thousand-years/The relationship between humans and dogs began beside a campfire 30,000 years ago. Was it a contract, or was it love? When your dog looks at you, you are gazing upon ten thousand years of trust.https://www.parkjunwoo.com/opinion/most-beautiful-social-contract/Fri, 23 Jan 2026 09:38:00 +0900https://www.parkjunwoo.com/opinion/most-beautiful-social-contract/Santa Claus is not merely a ‘deception’ – he is the most beautiful ‘cultural promise’ and ‘collective narrative’ that humanity created to protect childhood wonder.https://www.parkjunwoo.com/dabel/about/Mon, 01 Jan 0001 00:00:00 +0000https://www.parkjunwoo.com/dabel/about/https://www.parkjunwoo.com/languages/Mon, 01 Jan 0001 00:00:00 +0000https://www.parkjunwoo.com/languages/