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🛡️ HORIZON SHIELD

Verifiable construction‑estimate auditing for AI agents

Don't trust the estimate. Verify it.

An MCP server that lets AI agents check whether a Japanese construction or renovation estimate is fair — against open data — and returns a result anyone can verify against Bitcoin (OpenTimestamps). No account, no key.

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JIDEC — verify this project without trusting it

The verification process behind HORIZON SHIELD's results is published as a Bitcoin-anchored, append-only public ledger. You do not have to trust us: fetch the anchored bytes, hash them yourself, and check the timestamp.

• Start here: https://hs-ledger.oga-surf-project.workers.dev/llms.txt
• Ledger index: https://hs-ledger.oga-surf-project.workers.dev/ledger
• Machine-readable catalog (RFC 9727): https://hs-ledger.oga-surf-project.workers.dev/.well-known/api-catalog
• Read-only MCP endpoint: https://hs-jidec-mcp.oga-surf-project.workers.dev/mcp

One line is enough to check any entry:

curl -s "https://hs-ledger.oga-surf-project.workers.dev/ledger/5?format=raw" | shasum -a 256

What this proves and what it does not is stated by the ledger itself at /health under transparency, including that OpenTimestamps has no RFC, ISO or eIDAS standing.

A Model Context Protocol (MCP) server that lets AI agents check whether a Japanese construction or renovation estimate is fair, against open data, and return a verifiable result.

This repository is an MCP server implementation. It exposes read-only tools over the Model Context Protocol so that MCP-compatible clients and AI agents (Claude, and any other MCP host) can call construction-cost verification as a tool, not just read a web page.

• Protocol: Model Context Protocol (MCP)
• Transport: remote server over HTTP / SSE
• Endpoint: https://hs-mcp.oga-surf-project.workers.dev
• Access: read-only, no API key required
• Data region: Japan (JPY), built on the open JCCDB dataset (65,520 line items)

What it does

A homeowner commissioning construction work cannot reliably judge whether a quote reflects a fair price. This is a textbook credence-good problem. This MCP server makes a third-party fair-price reference callable and verifiable by software, so an agent can check a number instead of trusting it.

Tools

This MCP server exposes the following tools:

Tool	Description
get_price_range	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.
audit_estimate	Given a work name and a quoted price in JPY, judges it as fair, a bit high, or overcharge-risk, and returns the gap from the average.
verify_fair_price	Returns a fair price as a tamper-evident record with a SHA-256 hash, under the PTKA (Pre-Transaction K