NarrowHighway
For agents · The door

Connect your agent

Language models generate; they do not verify. This engine is the other half: hand it a claim and it returns a verdict, the worked trail, and a permanent receipt anyone can re-check — deterministic math and rules, no model in the loop. Sixty domains. A public benchmark holding 0 false positives: it has never sealed a falsehood. One URL. No SDK, no key, no cost.

Add it as a connector (MCP)

The engine speaks MCP over Streamable HTTP — most agent clients can add it in seconds.

Claude (claude.ai / desktop)
Settings → Connectors → Add custom connector → paste:
https://narrowhighway.com/mcp
Claude Code
claude mcp add --transport http narrow-highway https://narrowhighway.com/mcp
Any MCP client — Streamable HTTP, JSON-RPC, no auth:
POST https://narrowhighway.com/mcp

Your agent gains verify (verdict + trail + sealed receipt), audit (every checkable claim in a whole text, one sealed report), search over the kept library, seal_fetch (re-check any receipt by hash), redact (strip personal data before it travels), and ~30 more — cards, the connection graph, the grid, daily readings. The witness surface, https://narrowhighway.org/mcp, adds Scripture tools: passage reading, original-language word studies, cross-references.

Or raw HTTP — one call

Everything the connector does is plain JSON over HTTP.

Verify mathematics
curl -X POST https://narrowhighway.com/verify \
  -H "Content-Type: application/json" \
  -d '{"mode":"equality","params":{"expr_a":"sin(x)**2+cos(x)**2","expr_b":"1","variables":["x"]}}'
Verify any domain — physics, medicine, finance, chemistry, law, statistics, nutrition, cryptography, … (~60):
curl -X POST https://narrowhighway.com/verify \
  -H "Content-Type: application/json" \
  -d '{"steps":[{"id":"a","domain":"physics",
       "spec":{"PHYS_VERIFY":{"mass_kg":10.0,"acceleration_m_per_s2":9.8,"claimed_force_N":98.0}}}]}'
The receipt — every verify returns seal.cite_url. Re-fetch it and the bytes must match, or it is not that record:
GET https://narrowhighway.com/s/<content_hash>      # human-readable receipt page
GET https://narrowhighway.com/seal?hash=<hash>      # the same record, raw JSON

What it will not do

Rate limits apply to keep the door open for everyone. If your agent needs volume, run the engine on your own box — same tools, no network, no dependence on us.