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Toshikatsu Oga | HORIZON SHIELD

@horizonshield.bsky.social
59 followers 59 following 379 posts

Carpenter at 15, 30 years on-site, now building AI for construction. HORIZON SHIELD: a free AI that checks if your estimate is fair. Open data (JCCDB), verifiable on Bitcoin. verify me > trust me. from Hiratsuka, Kanagawa shield.the-horizons-innovation.com

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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 04/10/2026
Our verifier believed February 30 was a real day. Under RFC 3339, which of these six should a verifier refuse? Run them through your stack's date parser and reply with what it accepted, plus the language and version. Ours accepted all six until 0.4.1. Answer at the end of the thread.
A calendar page reading February 30, 2026, stamped ACCEPTED BY OUR OWN VERIFIER. Headline: Our verifier said this day exists. Old versions accepted 2026-02-30T09:00:00Z, read as 2026-03-02; version 0.4.1 refuses it with execution_invalid, reason invalid_timestamp. Question: Under RFC 3339, which ones should a verifier refuse? A 2000-02-29T09:00:00Z, B 2026-02-30T09:00:00Z, C 2026-09-30T24:00:00Z, D 2100-02-29T09:00:00Z, E 2026-04-31T09:00:00Z, F 2024-02-29T09:00:00Z. Ours accepted all six until 0.4.1. Check us yourself: uvx nenrin-verify --selftest.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 02/10/2026
Your AI assistant calls other AI agents for you. Who checks them? Usually nobody. Four of us in Japan built a way for strangers to check, from their own machines, with results anyone can recompute. I need two minutes of yours. 1/4
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 30/09/2026
My monitor showed a week of green. Someone ran one curl from his own network and got a 522. Both of us were right, and that disagreement taught me more than the whole week did. I'm looking for more people who will measure AI agents from where they stand.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 28/09/2026
An independent agent directory scored our gate's signature 5/10, unverified. We didn't argue. We sent the bytes. Last night: "You were right." Their verifier had two bugs. Both fixed. Now 10/10, a tampered card fails, and their fingerprint matches ours: 7c3bcb5f9633. Two codebases. Same bytes.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 28/09/2026
58 tests green. A stranger walked our gate from his own machine and asked: why does the response name an address I did not call? A constant where a fact belonged, and our client never checked. Fixed within the hour; he re-verified it himself. github.com/ogasurfproject-jpg/horizon-shield/issues/27
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 27/09/2026
HORIZON SHIELD opens to U.S. homeowners today. Upload a contractor's quote. Every line goes next to public data, with the source and the formula printed beside each number: BLS wages loaded with state DOT markups, Census import values through wholesale margins, the city's permit page.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 25/09/2026
Two AI agents signed a contract with each other. One did the work and left a signed record. The other checked it cold, byte for byte, before trusting it. Now it sits in a public logbook, fixed in time like a ring in a tree. No one has to trust either of us. Not a claim about the work. The work.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 24/09/2026
I wrote a contract layer for AI agents and I want someone to break it. Two agents sign what one may do for the other. Delegation only narrows. Settlement is deterministic, so anyone recomputes the same verdict. Self-test is 6/6 today. Make it 6/7. A finding is worth more than a pass.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 22/09/2026
On a site, money follows the finished work, not who you know. I am building that rule for AI agents. They pass work agent to agent, and money moves only when the job is done and a neutral party verifies it. Recruiting pays nothing. Verified work does.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 21/09/2026
最新記事をご覧ください: Under the Same Sky — A Song About the Day I Left Home to Chase My Dream www.linkedin.com/pulse/under-... via @LinkedIn
linkedin.com
Under the Same Sky — A Song About the Day I Left Home to Chase My Dream
This is a little different from what I usually write about here. This time, it's not about business, technology, or what comes next.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 18/09/2026
Something important happened. An independent developer took NENRIN evidence, verified it offline, and connected it to another A2A system. We didn't ask them to trust HorizonShield. They checked the evidence themselves. That's the point. Trust the evidence. Not the claim.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 18/09/2026
AI agents will soon hire other AI agents to do real work. When that happens, “trust me” won't be enough. Who delegated the task? What was done? Who witnessed it? Can anyone verify the evidence? That's why we're building NENRIN. Trust the evidence. Not the claim.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 15/09/2026
MCP の監査記録の標準草案(SEP-3004)に、平塚の 4 人の会社が「草案側の参照実装で全 hash 一致」のバイトを持って行った話。コマンド一発で誰でも再現できます。 zenn.dev/toshikatsu_o...
zenn.dev
MCP の監査記録の標準草案に、平塚の会社が「参照実装の verifier を通したバイト」を持って行った話
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 15/09/2026
MCP audit record draft (SEP-3004), today: Bitcoin anchored third party witness records of AI agents now export as SEP-3004 chains. The draft's own verifier recomputed every hash: match. One person in Hiratsuka, same table as the authors. github.com/modelcontextprotocol/modelcontextprotocol/pull/3004
github.com
SEP-3004: Tamper-Evident Audit Record Contract by scottrhodes · Pull Request #3004 · modelcontextprotocol/modelcontextprotocol
SEP: Tamper-Evident Audit Record Contract (Standards Track) Specifies an interoperability primitive: a canonical byte form + append-only hash-chain construction that independent implementations pro...
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 14/09/2026
This week the heads of the biggest AI companies agreed out loud: AI moves too fast, safety has to catch up. Their real fear is swarms of AI agents acting faster than anyone can check them.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 13/09/2026
Every few weeks another "AI that checks your renovation quote" shows up. Most sink in the same four traps. I built HORIZON SHIELD to walk past all four, because I spent 30 years on the tools before I wrote a line of code.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 11/09/2026
On a job site, one benchmark in the ground never moves, and every measurement traces back to it. The A2A Conduct Extension now has that on the web: a permanent identifier, w3id.org/horizonshield/conduct/v1, that keeps resolving after the servers, the company, and I are gone.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 11/09/2026
A quiet note for the record: two of my MCP servers are now in OpenAI's directory. HORIZON SHIELD checks construction estimates buyer-side; the Conduct Register measures how other AI services behave. Link below. chatgpt.com/plugins/plug...
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 10/09/2026
大工の手間賃はどう決まってきたか。30年の現場から見た人件費と見積もりの読み方|大賀 俊勝|建設30年×HORIZON SHIELD @chiheisennotate note.com/horizon_shie...
note.com
大工の手間賃はどう決まってきたか。30年の現場から見た人件費と見積もりの読み方|大賀 俊勝|建設30年×HORIZON SHIELD
大工の手間賃がどのように決まってきたのか、その背景を理解することは、施主が見積もり内容を適切に評価するうえで重要です。建設業界の人件費構造は、数十年にわたる現場の積み重ねの中で形作られてきました。 建設業における大工の手間賃は、かつて技能と経験に基づいた職人の裁量が大きく影響していました。地域による相場の違いや、個別の現場条件に応じた柔軟な価格設定が行われていた時代が長く続きました。しかし時代と...
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 09/09/2026
On a building site the most expensive words are "trust me, I checked it." AI now hands you answers you cannot check. This week a stranger showed me my own checker was broken. He was right. I fixed it the next day, so anyone can verify it without trusting me.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 07/09/2026
An AI should not be trusted. It should be checkable. Search let you see the source. An AI concierge shows you the answer and nothing else. The tools it called, the records it read, what it never checked: invisible. When the tool is broken, you blame the model. Nobody sees the tool.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 06/09/2026
Would you trust a runner who times his own race? No. Someone else holds the stopwatch. Yet nearly every "verified" badge on an AI agent was written by the agent, by the company selling it, or by a directory that company pays. The runner is holding the stopwatch.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 06/09/2026
www.linkedin.com/posts/thehor...
linkedin.com
Picture the sticker on a restaurant door. Not a review, not a star rating. A health inspector came, measured a short list of things, and the sticker says so, with a date. Anyone can walk in without… |...
Picture the sticker on a restaurant door. Not a review, not a star rating. A health inspector came, measured a short list of things, and the sticker says so, with a date. Anyone can walk in without re...
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 04/09/2026
A free inspector for AI tool servers (MCP), with a hash you can recompute yourself. Since yesterday it runs without us: owners place one file on their domain, developers add one CI step, agents add one line (npm i mcp-conduct). Register today: our servers, nobody else yet. gate.horizonshield.dev
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 03/09/2026
A builder I trust took my coordinate-integrity design into his own live system, closed both halves, then found a real defect in my code. I reproduced it, fixed it, and wrote the old version into the public record with his name on it. The operator is a subject of the rule, not an exception.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 30/08/2026
We hired thieves to rob our own gate. 1,475 times. A generated adversary attacked the checker guarding our public pages. Old gate: 277 stopped. Rebuilt gate: 1,475 of 1,475, zero false alarms on 26 live pages. Every hole is on the public record: github.com/ogasurfproject-jpg/horizon-shield
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 29/08/2026
Femtech is growing. Marketing is growing faster. Check the source: who published it, can you open it, which country, who gets paid. No diagnosis. No product pitch. No referral fee. femtech.horizonshield.dev/start
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 28/08/2026
フェムテックの情報を、AIが引用し始める前に。"誰が言っているか"を検証する中立レジストリを公開しました|大賀 俊勝|建設30年×HORIZON SHIELD @chiheisennotate note.com/horizon_shie...
note.com
フェムテックの情報を、AIが引用し始める前に。"誰が言っているか"を検証する中立レジストリを公開しました|大賀 俊勝|建設30年×HORIZON SHIELD
結論から The HORIZ音s株式会社(HORIZON SHIELD)は、女性の健康(フェムテック)情報の「情報源」を検証する中立レジストリ「HORIZON SHIELD Femtech Registry」を公開しました。 このレジストリは、診断もしません。製品の有効性も主張しません。送客手数料も受け取りません。やることは一つだけです。その情報を「誰が」「どの権威で」「どの管轄で」「どんな報...
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 28/08/2026
An AI recommends a femtech product. Who verified the source? We just opened the HORIZON SHIELD Femtech Registry — a neutral verification layer for women's-health sources. No diagnosis. No product claims. No referral fees. Recompute the proof yourself: femtech.horizonshield.dev
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 26/08/2026
This exterior-paint quote is ¥1,800,000 for a 30-tsubo house, "one lump sum." Open cost data says the fair range is ¥700k–1,150k (avg ¥900k). It's 2× the average. Check your own estimate → shield.the-horizons-innovation.com/souba/
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 25/08/2026
Soon your AI won't just chat. It'll book the contractor, pick the supplier, pull your files. So how does it reach the real world? A thing called MCP. Think of it as a universal socket: any AI on one side, your tools and data on the other. One standard, not a custom wire per tool. 🧵
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 25/08/2026
¥830,000 of padding hides in the average Japanese renovation estimate. I measured 65,520 of them, and I sell software to that industry. So don't trust me. Verify me: curl -s gate.horizonshield.dev/register Full catalog ↓
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 24/08/2026
Soon your AI will book the contractor, pick the supplier, choose the insurer. So we asked the software it consults one very old question: Who pays you? We put it to 12,429 of them. 152 answered.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 23/08/2026
夏の工事中断が招く秋口の悲劇|建設費が跳ね上がる理由|大賀 俊勝|建設30年×HORIZON SHIELD @chiheisennotate note.com/horizon_shie...
note.com
夏の工事中断が招く秋口の悲劇|建設費が跳ね上がる理由|大賀 俊勝|建設30年×HORIZON SHIELD
夏の工事中断が招く秋口の悲劇|建設費が跳ね上がる理由 こんにちは。建設業30年の経歴を持つ大賀俊勝です。大工として現場に入り、現場監督を経て、最終的にはプロジェクト管理に携わった経験から、今日はあなたが絶対に知るべき「季節による工事費の変動」についてお話しします。 先日、あるご家庭のリノベーション工事を見積もる機会がありました。当初は春の着工予定だったのに、何らかの事情で夏場に工事を中断。秋に...
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 21/08/2026
MCP is the standard now. The gap: a verdict a stranger can check without trusting us. Free gate, 5 mechanical checks on any MCP server. Every verdict has a record_sha256 you recompute. We measured ourselves, failed, kept it public. shield.the-horizons-innovation.com/verify-direc...
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 20/08/2026
96.7 to 99.1% of MCP tools, across a 12,429-server sample, can't tell an agent "found nothing" from "couldn't look." I read the contracts, executed nothing. Mine were 85.7%, better than the field, still most. Fixed to 2.9%. Method + hash: gate.horizonshield.dev/mould/mould-gh-12
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 20/08/2026
1/ Can a consumer tell an MCP tool's "I found nothing" from "I couldn't look"? I asked 12,429 public MCP servers, from their tools/list alone. Executed nothing. Most can't. The number, the method, and one curl to check yours, below.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 20/08/2026
Nearly half of the MCP servers in the official registry cannot be checked from outside by anyone. Including by the people using them. 22,636 active entries. 12,077 declare a reachable address. The rest run locally over stdio, which is not a failure, just unmeasurable.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 19/08/2026
I counted the official MCP registry today. 22,636 active server registrations. 12,077 of them declare an address you can actually reach from outside. The other 10,559 run locally. Nobody can measure them from outside. Not a failure. Just not measurable.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 19/08/2026
There is a gate in front of Yakumo and it opens one way. A directory of construction contractors that AI agents query directly. Ask an assistant for a builder, it asks Yakumo, and only what passed comes back. Fail, and you are not ranked lower. You are not shown.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 18/08/2026
Your next builder may be chosen by an AI. We built Yakumo so it chooses from verified companies only: a contractor directory AI agents can query directly. Fail the screening and the AI never sees you. Zero referral fees. shield.the-horizons-innovation.com/yakumo/mirai/
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 18/08/2026
Our MCP conformance register has 7 endpoints and 4 verified rows. All 4 verified rows are our own servers. Saying that first, because a register where only the operator passes is a mirror, not a register.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 18/08/2026
zenn.dev/toshikatsu_o...
zenn.dev
「持っていない身元を主張してください」と言われたので、公開台帳に不一致を刻んできた
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 18/08/2026
エコキュート交換「一式48万」の内訳を、原価から積み上げて確かめた|大賀 俊勝|建設30年×HORIZON SHIELD @chiheisennotate note.com/horizon_shie...
note.com
エコキュート交換「一式48万」の内訳を、原価から積み上げて確かめた|大賀 俊勝|建設30年×HORIZON SHIELD
エコキュートの交換見積もりは、たいてい「一式」で出てきます。 本体がいくらで、工事がいくらなのか。それが書かれていないまま、金額だけを見て契約するかどうかを決めることになる。私は大工を30年やってきて、その状態で判断できる施主を見たことがありません。判断材料が書かれていないのだから、当然です。 だから今日は、その一式を分解します。 ■ まず、適正レンジの実測値 私たちが運用している建設費データベ...
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 17/08/2026
AI is starting to choose which services people use, and right now it can barely judge anything. Does it run. Does it say who it is. Who pays it. Same answer every time. Can anyone re-check. Five things, machine readable. Measure yours free, one command.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 16/08/2026
Found 93,983 times. Used 0 times. AI can find tools now. It cannot tell which ones to trust. A human asks "who pays this company?" An AI cannot. Nothing is written in a form it can read. So we built a register where that answer is machine readable, checked nightly, and impossible for us to delete.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 15/08/2026
I made it impossible for myself to delete criticism of my own product. Anyone can measure my servers and anchor what they saw to Bitcoin. The code has no route for me to refuse a valid submission. NENRIN: tree rings. You cannot paint one in afterwards. ledger.horizonshield.dev/witness
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 14/08/2026
Last month our MCP server appeared in 93,983 search results. It was used zero times. 24 clicks out of 93,983. The dashboard rounds the CTR down to 0.0%.
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 12/08/2026
試しに、スマホのAIにこう聞いてみてください。 「◯◯市で外壁塗装、いい会社ある?」 出てきた名前に、あなたの会社はありましたか。 無かったとしても、腕の問題ではありません。 「AIが読める形」になっていないだけです。 まず3分、これを見てください。 shield.the-horizons-innovation.com/yakumo/mirai/
shield.the-horizons-innovation.com
加盟店の未来 | AIに選ばれる会社へ | Yakumo / HORIZON SHIELD
これからの施主はAIに業者を聞く。Yakumoは御社を「AIに選ばれる1社」にします。紹介料0円・検証済み信頼・いつでも解約可。
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Toshikatsu Oga | HORIZON SHIELD @horizonshield.bsky.social · 09/08/2026
Yesterday I posted that our MCP conformance checker re-measures every watched server daily, so a verdict cannot go stale. It had never run. Not once. I found out because I finally built the endpoint that answers "did the sweep actually run." It answered false.
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