AINumbers MCP Apps Server

An agent calling a fintech tool by name has no way to know if the tool actually ran the math it claims to have run. This server closes that gap for the AINumbers.co suite: every tool call is deterministic, zero PII, and served straight from the suite's own single-file HTML, not a paraphrase of it.

An MCP Apps (SEP-1865) server that exposes the AINumbers.co fintech tool suite to any MCP host, including Claude, ChatGPT, M365 Copilot, VS Code, and Cursor.

Quick start

# Claude: Settings -> Connectors -> Add custom connector
https://mcp.ainumbers.co/mcp

# Inspector
npx @modelcontextprotocol/inspector   # then Streamable HTTP -> the URL above

No auth, no API key, no account. Production runs on Cloudflare Workers (/healthz reports runtime: cloudflare-workers), so there are no cold starts. Cursor and other Open Plugins directories pick this repo up automatically via the root .mcp.json, which declares the same endpoint.

Live endpoint: https://mcp.ainumbers.co/mcp (streamable HTTP) · Docs: ainumbers.co/mcp.html · Registry: co.ainumbers/tools on the Official MCP Registry

Related MCP server: Xero MCP Server

Tools

Read-only MCP tools — count intentionally not hardcoded here (it drifted stale the last time it was). See data/counts.json for the live figure; never hand-type this number, scripts/surface-parity.mjs and the site repo's count-drift gate both check against it. Fifteen tools render as interactive widgets, the rest are ChainGraph compute nodes plus a handful of catalog and discovery utility tools: list_ainumbers_tools, find_tool, find_chain, build_workflow_links, run_chain, verify_execution_hash, build_chaingraph, emit_chaingraph_artifact, build_session_receipt.

Every tool declares readOnlyHint: true. No account, no auth, zero PII, nothing mutates state.

The 15 flagship widgets

Each renders as the actual single-file AINumbers tool, served as a text/html;profile=mcp-app resource and driven by the AIN Bridge (prefill, run, Policy Mandate export):

list_ainumbers_tools and find_tool search the full catalog (see data/counts.json for the current tool count) and return deep-links. Prefill-enabled tools accept #in=<base64url(JSON of {element_id: value})>[&run=1] for one-click invocation. find_chain and build_workflow_links return ordered deep-links for a named multi-tool workflow. run_chain executes one server-side. verify_execution_hash independently re-verifies a returned artifact's hash.

Architecture

../repo (site repo, PostOakLabs/ainumbers)
   |  chaingraph.json, manifests/, pilot.mjs-referenced tool HTML
   |
   v  node generate.mjs (build-time only, cannot run in cloud CI, needs the sibling repo)
data/       vendored: chaingraph.json, catalog.json, manifests, counts.json
kernels/    vendored: server-side compute kernels
   |
   v
worker.mjs  (Cloudflare Workers, this repo's live runtime)
server.mjs  (Node/express variant, local dev only, not deployed)
   |
   v
https://mcp.ainumbers.co/mcp   (the one live endpoint: the Worker, not the express variant)

data/ and kernels/ are generated, committed artifacts. The Worker boots from what's committed, not from a live read of ../repo. Any change to chaingraph.json, a manifest, pilot.mjs, or a kernel in the site repo requires re-running generate.mjs here and committing data/ and kernels/ in the same push, or the worker deploys stale.

Deploy flow (CI-owned)

Branch, then PR. CI runs the validate job: tool-name collisions, surface-parity, kernel coverage, chain validation, vendor-freshness, and a wrangler deploy --dry-run. Merging to master runs the deploy job, which runs wrangler deploy against Cloudflare Workers, then a post-deploy /mcp smoke test (a real initialize call against the live endpoint). No manual wrangler deploy, ever: Cloudflare Workers Builds stays disconnected on purpose, since running both is a double-deployer and has caused outages before. A green CI bundle does not by itself prove the live handshake works; only the smoke step does.

Dependabot auto-merges every dependency update (patch, minor, and major, all CI-gated), so run git pull --rebase before pushing any local branch since master moves on its own.

Develop

npm install
node generate.mjs   # re-vendor tool HTML + manifests + catalog + kernels from ../repo into data/ + kernels/
npm start           # http://localhost:3300/mcp (+ /healthz), Node/express variant (server.mjs), local dev only
node scripts/check-tool-names.mjs   # verify no mcp_name collision before pushing
node scripts/surface-parity.mjs     # verify counts.json matches the registered surface

pilot.mjs is the single source of truth for the widget tool set. After changing any pilot tool in the site repo, run node generate.mjs, commit data/ and kernels/, and push. CI validates and deploys.

All tool content is client-side, deterministic, and zero PII. Code is MIT licensed (see LICENSE); content is CC BY 4.0, Post Oak Labs. See README-SPEC.md for architecture and history.