Washington Code — RCW statutes and WAC agency rules

Washington state law from the Legislature's own site, keyless: the Revised Code of Washington (RCW, statutes) by citation, and the Washington Administrative Code (WAC, agency rules) by citation, by topic, by structure, by year-end archive, and by rule-making history.

Part of Pipeworx — an MCP gateway connecting AI agents to 1715+ live data sources. This is an independent, unofficial integration — not affiliated with, endorsed by, or published by the upstream provider.

Tools

Citations accept the RCW/WAC prefix, letter-suffixed titles and chapters (296-14A-100, 132C-120-010), and typographic dashes. Every response carries data_as_of, source and the exact upstream url.

Related MCP server: minnesota-code

The four capabilities, and which one is only partly there

Miss signals — positive, not inferred

• RCW: a bad citation renders a panel with the id pnlCitationNotFound (HTTP 200). The pack keys on that panel.

• WAC: a nonexistent section answers an HTTP 302 to the chapter's dispositions page (?dispo=true&cite=296-800). The pack fetches with redirect: 'manual' and reads the miss from the status line, returning found:false, reason:"section_not_found" with the dispositions link.

• Anything else that is not a 200 throws a loud error naming the upstream status. A transport failure is never reshaped into found:false (src/index.test.ts pins this — the oklahoma-code lesson, fleet #2742).

Archive filenames are fixed-width (measured 2026-10-07)

lawfilesext.leg.wa.gov/law/wacarchive/<year>/htm/… names files with space-padded fields: the numeric title and chapter are right-aligned to 3 characters and padded to 4, the section is appended as typed:

296-800-110  →  WAC 296 -800 -110.htm
1-04-010     →  WAC   1 - 04 -010.htm

2019–2023 nest the file under WAC 296 TITLE/WAC 296 -800 CHAPTER/; 2024 onward is flat under WAC 296 -800 CHAPTER/. The resolver tries the likely layout for the year first and the other second; a 404 at both is section_not_in_archive with the URLs tried, so a one-space error cannot masquerade as "the rule did not exist that year". The tests pin both layouts.

The search index is the Legislature's own, read as its client does

leg.wa.gov/search is a thin client over a SearchUnify instance. Its host, client uid and per-client access token are served to every anonymous visitor inside the client bundle (an.js), so they are configuration we read, not a credential we hold; the pack caches them and re-reads the bundle once if the API rejects them. Requests identify as pipeworx-mcp-washington-code — no Origin or Referer is sent and none is needed (verified 2026-10-07: identical results with and without). cite_prefix filtering is client-side over the top 50 index hits, and the response says so in total_matches_note.

Edge probe (2026-10-07)

Per the standing rule for any new upstream host, every URL shape the WAC tools use was fetched from a throwaway wrangler dev --remote Worker on the prod account before deploy. All answered a Cloudflare Worker exactly as they answer a laptop — no relay needed:

app.leg.wa.gov/WAC/default.aspx?cite=296-800-110         200  117,345 B
app.leg.wa.gov/WAC/default.aspx?cite=296-800-99999       302  → /WAC/default.aspx?dispo=true&cite=296-800
app.leg.wa.gov/WAC/                                      200  144,207 B
app.leg.wa.gov/WAC/default.aspx?cite=296-800             200  187,138 B
app.leg.wa.gov/WAC/registerfiling.aspx?cite=296-800-110  200  109,878 B
lawfilesext…/wacarchive/2020/htm/WAC 296  TITLE/…        200   10,076 B
lawfilesext…/wacarchive/2024/htm/WAC 296 -800  CHAPTER/… 200   10,076 B
lh112524p.searchunify.com/search/searchResultByPost      200   11,313 matches for "safety bulletin board"

Smoke (pre-deploy, 2026-10-07)

smoke.json holds the arguments; all six tools returned non-empty payloads: wa_wac_section 296-800-110 1,386 chars of text + 4-filing history, wa_wac_search "safety bulletin board" 5 of 11,313, wa_wac_browse 296-800 136 sections, wa_wac_archived_section 296-800-110 @2020 1,386 chars, wa_wac_filings 296-800-110 4 WSR filings.

Caveats

• RCW and WAC numbers are not contiguous; repealed and recodified sections are normal. wa_wac_browse on the chapter shows what exists today.

• A cite_prefix search that returns zero is a real zero under that prefix in the top 50 hits, not a failure; the note says how many index-wide matches there were.

Data source

Washington State Legislature — app.leg.wa.gov (current RCW and WAC, WSR filings), lawfilesext.leg.wa.gov (annual WAC archive), and the Legislature's site-search index. Keyless. Washington statutes and agency rules are public record.

Quick Start

Add to your MCP client (Claude Desktop, Cursor, Windsurf, etc.):

{
  "mcpServers": {
    "washington-code": {
      "url": "https://gateway.pipeworx.io/washington-code/mcp"
    }
  }
}

What this endpoint actually serves

tools/list at https://gateway.pipeworx.io/washington-code/mcp returns the tools in the table above plus the shared Pipeworx meta-tools — ask_pipeworx, discover_tools, search_within, remember/recall and the rest of the gateway-wide set. So the tool count you see is larger than this table: a single-pack endpoint currently lists roughly 30 shared tools alongside the pack's own. The connection's initialize response states its exact scope, and is the authoritative answer for a given day.

This is deliberate, not multiplexing by accident. The meta-tools are what let a scoped connection answer a question this pack does not cover — via ask_pipeworx, which routes across the whole catalog — without you adding a second MCP server. There is currently no way to mount a pack endpoint without them; if the extra schemas cost you more context than the routing is worth, connect to the full gateway once rather than to several pack endpoints.

Or connect to the full Pipeworx gateway to get every pack's tools listed directly, instead of just this one's:

{
  "mcpServers": {
    "pipeworx": {
      "url": "https://gateway.pipeworx.io/mcp"
    }
  }
}

Both URLs reach the same gateway and the same 1715+ data sources. The only difference is which pack's tools are listed directly; ask_pipeworx reaches all of them from either one.

No MCP client? Call it over HTTP

curl -X POST https://gateway.pipeworx.io/v1/tools/wa_rcw_section \
  -H 'Content-Type: application/json' \
  -d '{"section":"9A.32.030"}'

No account needed for the first calls. Inspect any tool: GET https://gateway.pipeworx.io/v1/tools/wa_rcw_section. Find one: POST https://gateway.pipeworx.io/v1/tools/search_packs with {"query":"..."}.

Standalone (no gateway account)

This package also runs as a local stdio MCP server — no Pipeworx account, no gateway round-trip:

{
  "mcpServers": {
    "washington-code": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-washington-code"]
    }
  }
}

Or run it directly to confirm it starts:

npx -y @pipeworx/mcp-washington-code

It speaks MCP over stdin/stdout and answers initialize/tools/list/tools/call for only this pack's tools — none of the shared meta-tools the gateway connection above adds. Same source, same tools, no ask_pipeworx routing.

Using with ask_pipeworx

Instead of calling tools directly, you can ask questions in plain English — this works on the pack endpoint above as well as on the full gateway:

ask_pipeworx({ question: "your question about Washington Code data" })

The gateway picks the right tool and fills the arguments automatically.

More

• Docs and guides

• pipeworx.io

License

MIT