HORIZON SHIELD: construction and renovation estimate auditor

io.github.ogasurfproject-jpgPublished by GitHub account ogasurfproject-jpgv1.1.0Updated Oct 24, 2026

Fair-price checks for Japanese renovation quotes, with sources and recomputable records.

VerifiedStreamable HTTPWeb executableFinanceData & AnalyticsBusiness & Commerce

Overview

AI-generated overview

A remote MCP server that checks Japanese construction and renovation quotes against a curated fair-price database and flags overcharge tactics.

What you can do
Look up fair price ranges, danger thresholds and sources for construction and renovation work categories, and search or list those categories by keyword or work name. Audit a specific quoted amount against the fair range, get a verdict, percentage gap and advice, or preview which way a rough estimate deviates from average. Check wording in an estimate or sales pitch for known overcharge and high-pressure tactics, and read general principles for judging any estimate. Issue and verify tamper-evident fair-price records with SHA-256 hashes, and get attestations and agent-card details. Query Japanese and U.S. construction cost datasets, including item catalogues, labor rates, permits, regional or
When to use it
Use it when a homeowner or buyer wants a second opinion on a Japanese renovation or construction estimate, needs a fair-price range before requesting quotes, or wants a checkable record of a fair price. Some tools, such as the red-flag check and reading guide, also apply to estimates outside Japan.
Requirements
A remote streamable HTTP endpoint; no authentication, API key or installation is declared. Fair-price verdicts are Japan-specific and in JPY. A Node.js 18 or later relay script is offered for stdio clients.
Before you install
The attestation tool does not move funds but appends a record to a public ledger on every call, so it is not read-only. Fair-price receipts and daily receipt lists are published at public URLs, and the anonymous review board link leads to a third-party posting form where personal details should be withheld. Fair-price data is Japan-specific and advisory.

Installation

In SourceWeft

  1. Open HORIZON SHIELD: construction and renovation estimate auditor in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.ogasurfproject-jpg%2Fhorizon-shield/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "horizon-shield-construction-and-renovati": {
      "type": "http",
      "url": "https://mcp.horizonshield.dev/"
    }
  }
}

README

HORIZON SHIELD - MCP server for construction-estimate integrity (Japan)

An independent, third-party auditor for Japanese construction & renovation estimates. Ask whether a quoted price is fair. It checks the number against a curated fair-price database (souba-db, supervised by Toshikatsu Oga - 30 years in the field), flags known overcharge tactics, and can return a tamper-evident fair-price receipt: a claim whose SHA-256 anyone can recompute, kept by the issuer at a public URL, under PTKA (Pre-Transaction Knowledge Anchoring). The AI doesn't just say "fair": it hands you a record you can check yourself. What is and is not anchored in Bitcoin is stated below.

Works with any MCP client: Claude | ChatGPT | Gemini | Perplexity | Cursor | Cline and more.

  • Remote endpoint (streamable HTTP): https://mcp.horizonshield.dev
  • No auth, no install - add the URL as a custom connector.
  • Registry name: io.github.ogasurfproject-jpg/horizon-shield
  • Operator: The HORIZONs Inc. | https://shield.the-horizons-innovation.com

日本の建設・リフォーム見積もりが適正かを、AIエージェントから「呼べる」中立の第三者監査。相場データ(souba-db／大賀俊勝 実務監修30年)と照合し、過剰請求の赤旗を検知し、誰でも SHA-256 を再計算できる適正価格のレシートまで返す。AIが「適正」と言うだけでなく、誰でも自分で確かめられる記録を出す。Bitcoin に刻印されているのは PTKA の宣言(block 949356)と、データの各版と、2026-10-19 からは毎日のレシートの一覧(前日分を翌日に JIDEC 台帳の 1 entry として刻む)。

Why it's different

  • Verifiable, not just an opinion. A fair-price receipt is a claim with its SHA-256 (SHA-256(JSON.stringify(claim))), served by the issuer at https://mcp.horizonshield.dev/ledger/<sha>. Recompute the hash yourself: once you hold it, the claim cannot change without the hash changing. audit_estimate also names the SHA-256 of the souba-db bytes it judged against, and dataset releases are anchored in Bitcoin through the JIDEC ledger (souba-db 2.3.0 = entry 114).
  • What is anchored and what is not. The PTKA protocol declaration is anchored in Bitcoin (block 949356, via OpenTimestamps); each receipt carries that block as the protocol it follows. From 2026-10-19 the receipts of each UTC day are listed at https://mcp.horizonshield.dev/ledger/day/<date>, and the next day that list (every receipt that recomputes) becomes one JIDEC ledger entry, stamped to Bitcoin by the ledger's stamping run (.github/workflows/receipt-anchor.yml, copies in ops/receipts/). That bounds a receipt's issue time from above by about a day. Receipts issued before 2026-10-19 were not listed.
  • Recorded before the quote (PTKA). A neutral fair price is recorded, with its issue time in the claim, before the contractor's estimate arrives.
  • Field-supervised data. souba-db is curated from multiple public price sources plus 30 years of on-site experience - not scraped guesses.

Tools (30)

Fair price, verification and contractors (15)

ToolWhat it does
get_price_rangeFair price range (min/avg/max), overcharge danger threshold, unit, trend
audit_estimateJudge a specific quoted amount vs the fair range - verdict, % gap, advice
verify_fair_priceFair price as a tamper-evident receipt (SHA-256 anyone can recompute, under PTKA)
check_red_flagsDetect overcharge / high-pressure sales tactics (lump-sum, today-only, etc.)
preview_reverse_estimateEarly-stage preview: which way a rough estimate deviates from average
search_cost_categoryFind a construction-cost category by keyword
list_cost_categoriesList the curated cost categories
get_estimate_reading_guideUniversal principles for judging any estimate (overhead ratio, lump-sum, tactics)
get_fair_price_sourcesSources, update date, and regional multipliers behind the data
get_anonymous_estimate_review_link (formerly suggest_ehn, which still answers)Guide and submission URL for EHN, the free anonymous third-party estimate review board
get_jccdb_dataset_infoJCCDB open dataset (v5.1: 526,128 records = 95,403 items + 430,725 observations, CC BY 4.0) - metadata & citation
verify_integrity_claimThird-party verification of an issued signed claim (fail-closed)
create_ap2_fairness_attestationFairPriceAttestation shaped to attach to a Google AP2 Cart Mandate (optional quoted_price adds within/above/below)
get_agent_cardA2A (Agent2Agent) agent card for agent interop
find_verified_contractorVerification-passed contractors on Yakumo (no referral or listing fee; scores and tiers, never prices)

Fair-price verdicts are Japan-specific (JPY). Several tools (check_red_flags, get_estimate_reading_guide) are language-agnostic and work for estimates anywhere.

Construction cost data: Japan (JCCDB) and both countries (7)

ToolWhat it does
search_jccdb_itemsSearch the JCCDB item catalogue (95,403 line items) by name, with evidence URLs
get_jccdb_observationsRegion, date and price status of an item in Japanese and U.S. public documents (licence and source on every row)
get_jccdb_labor_rateMLIT public-works design labor rates by prefecture and trade
compare_jccdb_regionsLatest value per region for an item and spec (min, median, max)
get_jccdb_work_unit_pricePublic-works unit prices for work items with composition ratios
get_jccdb_index_seriesConstruction cost index series with computed year-over-year change
get_jccdb_coverageWhat the observation layers hold, and what is absent

Construction cost data: United States (USCCDB) (8)

USCCDB is the United States Construction Cost Database. The four chain tools (get_us_price_chain, get_us_import_landed_cost, get_us_trade_margins, get_us_contract_discounts) compute on request and are not distributed as files.

ToolWhat it does
get_us_construction_pricesU.S. public construction cost data by layer, region, period and item
get_us_prevailing_wageDavis-Bacon prevailing wages by state, county and trade
get_us_permitsU.S. building permits and declared valuations by region and year
get_us_area_factorDoD and USACE location cost factors
get_us_price_chainEstimated U.S. prices from landed import cost to wholesale, retail and contractor (computed on request)
get_us_import_landed_costLanded cost of U.S. imports by HS code, duty included
get_us_trade_marginsU.S. wholesale and retail gross margins by NAICS
get_us_contract_discountsDiscount rates off list price in U.S. public contracts

Try it

bash
# server infocurl https://mcp.horizonshield.dev
# list tools (JSON-RPC 2.0)curl -X POST https://mcp.horizonshield.dev \  -H "Content-Type: application/json" \  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Add it to your AI

  • Claude / ChatGPT / Gemini: Settings -> Connectors / Custom apps -> add the remote URL above.
  • Programmatic: any MCP client that speaks streamable HTTP JSON-RPC (stateless).
  • stdio clients and registry crawlers: node workers/hs-mcp/stdio.js (from the repository root) relays stdio JSON-RPC to the remote endpoint above. It holds no server code and has no dependencies (Node 18 or later); HS_MCP_URL points it elsewhere. Behind an HTTPS proxy, run it with NODE_USE_ENV_PROXY=1.

Deploy (maintainer)

The server source is not in this repository. The maintainer deploys from a private working tree with this folder's wrangler.jsonc (bindings: RL_KV, HEARING_SVC, JCCDB_SVC); this folder holds the listing metadata and the conformance tests.

License & data

Tool logic (c) The HORIZONs Inc. Underlying open data: JCCDB (CC BY 4.0). souba-db is a curated reference maintained by HORIZON SHIELD.

Source: workers/hs-mcp/README.md at commit 60e6a43

Tools

15

get_jccdb_dataset_info

Get JCCDB Dataset Info

日本の建設費オープンデータベース(JCCDB)のメタデータ・規模・ライセンス・ダウンロードリンク・引用情報を返す。建設費の一次データ源を探している時に使う。 / Returns metadata, scale, license, download links and citation for the Japan Construction Cost Database (JCCDB), an open dataset of 526,128 records in v5.1: the item catalogue of 95,403 Japanese construction line items (43,090 verified + 52,313 extended, unchanged since v4.0) and 430,725 source-cited observations. Use when looking for a primary construction-cost data source.

Takes no parameters.

list_cost_categories

List Cost Categories

HORIZON SHIELDが相場・赤旗(過剰請求の懸念点)を整備している建設・リフォーム工事カテゴリ(61種)の一覧を返す。 / Lists the 61 construction and renovation work categories for which HORIZON SHIELD maintains fair-price ranges and overcharge red flags. Japan-specific data.

Takes no parameters.

search_cost_category

Search Cost Category

工事名・キーワードで建設費カテゴリを検索する(例: 外壁塗装, 浴室, 給湯器, 雨漏り)。該当カテゴリと整備済みの赤旗件数・優先度を返す。 / Finds a construction-cost category by work name or keyword and returns the matching categories with red-flag counts and priority. Japan-specific; a Japanese query works best (e.g. 外壁塗装 exterior painting, 浴室 bathroom).

Parametersqueryrequired

get_estimate_reading_guide

Get Estimate Reading Guide

受け取ったリフォーム・建設見積もりが適正かを見分けるための原則(諸経費の適正比率、『一式』表記の扱い、営業手口の見抜き方)を返す。30年の現場経験に基づく判断軸。 / Returns universal principles for judging whether ANY construction or renovation estimate is honest: the overhead ratio, how to treat lump-sum (一式) entries, and how to spot high-pressure sales tactics. Language-agnostic and works outside Japan. Based on 30 years of field experience.

Takes no parameters.

get_fair_price_sources

Get Fair Price Data Sources

HORIZON SHIELDの相場データ(souba-db)の出典・更新日・地域係数を返す。価格の根拠を確認したい時に使う。 / Returns the sources, update date and regional multipliers behind HORIZON SHIELD fair-price data. Japan. Use to check the basis of a price.

Takes no parameters.

get_price_range

Get Fair Price Range

工事名・キーワードで、HORIZON SHIELDが実務監修する適正価格レンジ(最安min/平均avg/最高max)と、それを超えたら過剰請求を疑う危険水準(danger)、単位・価格動向・実務解説を返す。建設・リフォーム費用が適正か数値で確かめたい時に使う(例: 外壁塗装, 給湯器, ユニットバス, クロス)。返り値の next_actions.actions の先頭(id: reverse_estimate)は、見積もりを取る前の人が自分の家の条件で適正価格の幅を無料・登録なしで出せるページで、url に照会した工事名が入る。 / Returns the fair price range (min, avg, max), the overcharge danger threshold, unit, price trend and field notes for a Japanese construction or renovation job. Japan-specific pricing in JPY. Use to numerically check whether a cost is fair. The first entry of next_actions.actions (id reverse_estimate) is a free, no-sign-up page where a user who has no quote yet gets a fair price range for their own house; its url carries the queried work name. Trigger phrases: 相場, 適正価格, いくらかかる, 高い?, how much does this cost in Japan, is this price normal, what should I expect to pay.

Parametersqueryrequiredregion

audit_estimate

Audit Estimate Against Fair Price

業者が提示した見積金額が適正かを、HORIZON SHIELDの適正レンジ(souba-db, 大賀俊勝 実務監修)と照合して判定する。手元に具体的な見積額がある時に使う。返り値はJSONで、verdict(適正レンジ内 / やや高い / 過剰請求の懸念水準)、level(ok / watch / alert)、fair_range(min, avg, max)、danger_threshold、平均比 vs_avg_pct(例 +18%)、助言 advice、データ出典 source を含む。工事名が見つからない場合、近い候補があれば did_you_mean として返す。単価(平米など)建ての工事に総額らしい金額を渡した場合は unit_mismatch の案内を返す。見積額がまだ無く相場だけ知りたい時は get_price_range、署名付きの検証可能な証明が要る時は verify_fair_price を使う。Japan only, JPY。 / Audits whether a contractor quoted price for a Japanese construction or renovation job is fair by comparing it against HORIZON SHIELD fair-price ranges (souba-db). Use when the user already has a specific quoted amount. Returns a JSON object with verdict, level (ok, watch, alert), fair_range (min, avg, max), danger_threshold, percentage gap versus the average (vs_avg_pct, e.g. +18%), advice, and data source. If the work name has no match, close candidates may be returned as did_you_mean. If the work is priced per unit and the amount looks like a total, a unit_mismatch notice is returned instead. For the typical range only use get_price_range; for a signed verifiable attestation use verify_fair_price. Trigger phrases: この見積もり高い?, 適正?, ぼったくり?, 妥当?, is this quote fair, am I being overcharged, is this a rip-off.

Parametersworkrequiredregionquoted_pricerequired

preview_reverse_estimate

Preview Reverse Estimate

リフォーム検討の初期段階向けのプレビューで、業者の概算が平均からどちらの方向にどの程度ずれているか(例: +20%高い方向)だけを返す。具体的な適正額(min/avg/max)や危険水準は返さない。手元に詳しい見積内訳がまだ無い段階での最初の一歩に向く。具体的な適正レンジが必要なら get_price_range、見積額の詳細診断は audit_estimate を使う。Japan only, JPY。 / A preview for early-stage renovation planning that returns only the direction of a contractor rough estimate versus the average (e.g. about +20% above). It does not return the specific fair range (min/avg/max) or danger threshold. Suited as a first step before a detailed breakdown exists. Use get_price_range for a typical range, audit_estimate for a detailed quote diagnosis.

Parametersworkrequiredquoted_pricerequired

check_red_flags

Check Estimate Red Flags

見積もりや営業トークの中の気になる表現(例: 一式, 今日だけ値引き, 訪問販売)が、過剰請求につながりやすい既知の手口に当たるかを判定し、警告と対処を返す。代表的な手口のみを判定する。 / Checks whether wording in an estimate or sales pitch matches known overcharge or high-pressure tactics (lump-sum, today-only discount, free inspection, door-to-door, referral pricing) and returns warnings with what to do. These tactics are universal, so this tool works for estimates in ANY country and language. Covers representative tactics only.

Parameterstextrequired

verify_fair_price

Verify Fair Price (Signed Receipt)

工事の適正価格を、検証可能な形(算出内容のSHA-256ハッシュ付き)で返す。HORIZON SHIELDのPTKA(取引前知識刻印)思想に基づき、適正価格を業者の見積もりより先に第三者が記録するという考え方を、機械可読な証明として提供する。エージェントが価格の真正性を検証したい時に使う。 / Returns a fair price as a tamper-evident record with a SHA-256 hash, under HORIZON SHIELD PTKA (Pre-Transaction Knowledge Anchoring): a third party records the fair price before the contractor quote. Japan price data. Use when an agent needs to verify price authenticity.

Parametersworkrequired

create_ap2_fairness_attestation

Create AP2 Fairness Attestation

このツールは決済を開始・承認・実行しません。資産・通貨・暗号資産の移動も行いません。発行するのは適正価格の証跡だけです。呼び出すたびに公開台帳へ記録を1件追加するため読み取り専用ではありません。 / This tool does not initiate, authorize, or execute any payment, and does not move funds, currency or crypto assets. It only issues a price-fairness attestation. Each call appends one record to the public ledger, so it is not read-only. AP2(Agent Payments Protocol)対応エージェント向けのブリッジ。決済カート(Cart Mandate)に添付できる適正価格の証跡(FairPriceAttestation)を発行する。AP2のMandateは『ユーザーがこの支払いを承認した』ことを検証可能にし、この証跡は『その価格が適正である』ことを検証可能にする。認可の検証と価値の検証、二つは並列レイヤー。quoted_price を渡すと適正レンジ判定(within/above/below)も同梱する。証跡は SHA-256 と公開台帳と verify_url で誰でも再計算検証できる。 / Bridge for AP2 (Agent Payments Protocol) agents: issues a FairPriceAttestation that a shopping or payments agent can attach to a Cart Mandate before asking the user to sign. AP2 mandates make authorization verifiable; this attestation makes value verifiable. Parallel layers. Pass quoted_price for a fair-range verdict (within, above, below). Independently verifiable via SHA-256, a public ledger and a verify_url. Japan construction and renovation pricing, JPY.

Parametersworkrequiredmerchantquoted_price

get_agent_card

Get A2A Agent Card

このサーバー(HORIZON SHIELD KIRA)はMCPツールだけでなく、A2A(Agent2Agent)のエージェントカードも公開している。外部のA2A対応エージェントから発見・連携したい場合の、エージェントカードURLと公開スキルの一覧を返す。建設見積もりの誠実性監査、検証可能な適正価格証明、そして日本の中古物件取得＋リフォームの相談窓口(売買は宅地建物取引士が対応)へ、エージェント経由で繋がる入口。 / Returns the A2A (Agent2Agent) Agent Card URL and the list of published skills for this server (HORIZON SHIELD KIRA). Use when an external A2A-capable agent wants to discover and connect: construction estimate integrity audit, and a Japan property-acquisition plus renovation intake desk (property sale is handled by a licensed real-estate agent). This is how agents reach the desk over A2A.

Takes no parameters.

verify_integrity_claim

Verify Integrity Claim

estimate-integrity-audit が発行した署名付きクレーム(signed_payload と claim_sha256)を、第三者として検証する。発行側 (verify_fair_price はPTKA価格の発行) とは責務が正反対で、デフォルト姿勢は不信・fail closed。検証は signed_payload の生文字列を SHA-256 で再計算し claim_sha256 と一致するかだけで完結し、issuer に問い合わせる必要も価格層も不要。判定は契約 0.3 の failure_reasons 準拠で、result(verified / partial / unverified)・failure_reason(stale_data / changed_scope / missing_evidence)・trigger(expired_declaration / changed_estimate_version / missing_receipt / unverifiable_chain)・recomputed_sha256・scope_check・audit_ruleset_recheck を返す。重要: verified は『この宣言が改ざんされていない』ことの証明であって『監査ルールが今も有効』である保証ではない(audit_ruleset_recheck は常に not_performed)。estimate_version を渡すと scope(見積もり内容が発行時から変わっていないか)も照合し、渡さない場合は scope_check:skipped を明示する。 / Verifies a signed integrity claim (signed_payload and claim_sha256) issued by estimate-integrity-audit, as an independent third party. Opposite posture to the issuing side: distrust by default, fail closed. Recomputes SHA-256 over the raw signed_payload string and checks it equals claim_sha256; no issuer contact and no price layer needed. Follows contract 0.3 failure_reasons. IMPORTANT: verified means the declaration is untampered, NOT that the audit ruleset is still valid (audit_ruleset_recheck is always not_performed). Pass estimate_version to also check scope (whether the estimate changed since issuance); if omitted, scope_check is skipped and stated explicitly.

Parametersclaim_sha256requiredsigned_payloadrequiredestimate_version

find_verified_contractor

Find Verified Contractor (Yakumo)

地域と工事名で、Yakumo(検証を通った加盟店だけが並ぶ建設モール)の検証済み施工店を探す。掲載は KIRA 適正診断の通過だけで決まり(fail-closed)、紹介料・掲載料は受け取らない中立の名簿。金額は出さずスコアとティアで示す。検証手続き中の店は pending として別に返す。条件に合う検証済みの店が無い時は 0 件と正直に返す(名簿は小さい)。価格の照会(get_price_range / audit_estimate)の後に、施主が『どこに頼めばいい』『信用できる業者は』と聞いた時に使う。 / Finds verification-passed contractors on Yakumo, a directory where listing depends only on passing the KIRA fairness audit (fail-closed) and no referral or listing fee is taken. Returns scores and tiers, never prices; pending stores are returned separately; returns 0 honestly when nothing matches (the directory is small). Use after a price check when the user asks who to hire or which contractor can be trusted. Trigger phrases: 業者を探したい, どこに頼めば, 信用できる工務店, find a contractor in Japan, who should I hire.

Parametersareawork

Version history

4
  1. v1.1.0LatestOct 2, 2026
  2. v1.0.11Sep 26, 2026
  3. v1.0.10Sep 26, 2026
  4. v1.0.9Sep 16, 2026

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