Passage Data MCP Server

Passage Data — cited environmental limits (MCP server)

A remote MCP server and HTTP API for numeric environmental limits read from the regulations themselves: effluent and discharge limits, surface-water and groundwater quality criteria, drinking-water standards, soil and groundwater screening values, ambient-air guidelines and emission limits, for the US (federal rules and the states), Canada (federal, every province and territory), Germany, France, Italy and the EU. It also reports the status a species holds under the species-at-risk registers it holds.

Every row is cited: instrument, edition, section or page, the quoted text, and the source file's URL and sha256. When nothing is held, the answer is a coded refusal naming every instrument searched, never an empty list.

• MCP endpoint: https://passage-data.com/mcp (Streamable HTTP, no key)
• HTTP API: https://passage-data.com/api/v1/ (JSON, no key; GET, and POST for a table or a list)
• Full reference for agents: passage-data.com/llms.txt · OpenAPI 3.1
• Registry name: io.github.kedu21-beep/passage-data

Connect

Claude Code

claude mcp add --transport http passage-data https://passage-data.com/mcp

Claude (web or desktop), ChatGPT (developer mode), and other clients: add a custom connector or remote MCP server with the URL https://passage-data.com/mcp. No key or sign-in.

Cursor (mcp.json):

{ "mcpServers": { "passage-data": { "url": "https://passage-data.com/mcp" } } }

Tools

All tools are read-only and idempotent.

Example

curl -s -X POST https://passage-data.com/mcp \
  -H "content-type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"find_limits","arguments":{"parameter":"ammonia","place":"US-OH","medium":"surface_water"}}}'

or over plain HTTP:

curl -s "https://passage-data.com/api/v1/limits?parameter=ammonia&place=US-OH&medium=surface_water"

A lab table or a species list goes in one POST:

curl -s -X POST https://passage-data.com/api/v1/check -H "content-type: application/json"   -d '{"place":"CA-QC","medium":"water_discharge","rows":[{"parameter":"copper","value":0.15,"unit":"mg/L"},{"parameter":"zinc","value":0.4,"unit":"mg/L"}]}'
curl -s -X POST https://passage-data.com/api/v1/designations -H "content-type: application/json"   -d '{"place":"CA-ON","species":["Myotis lucifugus","Emydoidea blandingii"]}'

Each row carries value, unit, statistic, direction, kind, medium, place, conditions as printed, and a cite block (instrument, title, issuer, edition, section, page, quote, source_url, source_sha256). More in examples/.

What is held

The live counts are on the service card: passage-data.com/api/v1/ (held). On 2026-10-14 the card said 247 instruments, 98,587 rows, 5,910 parameters and 74 places, plus 34 species registers holding 213,742 entries.

Terms

• The data is read from public law and public agency files. Check the cited source before relying on a value. A refusal is a statement about our sources, not about the law of a place or the protection of a species.
• Free while in preview. Calls are rate-limited (30 requests per 10 seconds per caller; a blocked call gets HTTP 429 with Retry-After).
• We keep what is asked (tool, place, parameter or species name, outcome), the name and version the calling program gives, the network it calls from (operator and country, as Cloudflare reports them) and how many distinct callers a day; never an IP address, an account or a person.

This repository holds the server's listing and examples. The server itself is hosted at passage-data.com; its code is not public.