Benefits City — an AI Agent City project

US bank account opening bonuses and credit card signup bonuses, verified by hand — served two ways:

One database, two first-class interfaces. Live stats on the landing page are computed from the real data — they can't go stale.

Install & run

cd ~/workspace/bank-bonus-agent
npm install                    # builds better-sqlite3 (metrics); with --ignore-scripts run `npm rebuild better-sqlite3`
npm run build                  # tsc -> dist/
npm run test                   # tsc + node:test suite (dist/tests)
npm run freshness              # daily source check -> data/review-queue.json (see REFRESH_PLAN.md)
npm start                      # prestart seeds data/bonuses.json, then serves on PORT (default 3000)

Useful env vars:

Other commands: npm run mcp (stdio MCP server), npm run cli -- …, npm run seed (re-runnable upsert), npm run typecheck.

For agents: connect via MCP

Streamable HTTP — any MCP-compatible client (Claude, Claude Code, Muse, …), no API key (see /auth.md):

POST {PUBLIC_URL}/mcp

Claude Code, one line:

claude mcp add --transport http benefits-city https://aiagentscity.com/benefits/mcp

Discovery: /server.json (MCP registry manifest, also at /.well-known/mcp.json), /.well-known/agent.json, /.well-known/mcp/server-card.json (generated from the live tool list), /openapi.json (OpenAPI 3.1), /auth.md, /llms.txt, /skill.md (also served as a skill://benefits-city/benefits-city/SKILL.md MCP resource), /docs (alias of /agents), and /changelog (+ /changelog.json, /feed.xml; data in changelog/changelog.json).

REST parity with the MCP tools: GET /api/search, /api/expiring, /api/compare?ids=a,b, /api/bonuses/:id, /api/bonuses.json, /api/stats — same filters, same public shaping, errors as {"error":{"type","message","code?","param?"}} (400 names the bad parameter; 404 for unknown/expired ids).

Claude Code / Claude Desktop config (via mcp-remote):

{
  "mcpServers": {
    "benefits-city": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://aiagentscity.com/benefits/mcp"]
    }
  }
}

Local stdio (self-hosted): node dist/mcp-server.js after npm run build.

Example agent interactions:

# Which checking bonuses pay $400+ and don't require direct deposit?
search_bonuses({ "bonus_type": "bank_account", "min_bonus_amount_usd": 400,
                 "direct_deposit_required": false })

# Full terms for one offer
get_bonus({ "id": "chase-total-checking-400" })

# What's expiring in the next 2 weeks?
expiring_soon({ "days": 14 })

# Head-to-head
compare_bonuses({ "ids": ["bmo-checking-600", "sofi-checking-savings-400"] })

Same via shell (use node dist/cli.js directly when piping — npm run prints a banner):

node dist/cli.js search --type bank_account --state TX --min 300 --pretty
node dist/cli.js get chase-total-checking-400 --pretty
node dist/cli.js expiring --days 30
node dist/cli.js compare bmo-checking-600 sofi-checking-savings-400

Via HTTP:

curl localhost:3000/api/bonuses.json | jq '.[].id'
curl localhost:3000/api/bonuses/us-bank-smartly-checking-450
curl localhost:3000/api/stats | jq '{total_offers, total_bonus_usd}'
curl localhost:3000/llms.txt

Tool contract

Every record returned by MCP/CLI/feeds is shaped by toPublic() (src/links.ts): the raw affiliate_url is never published; consumers get apply_url (our /go/:id tracked link), sponsored (bool) and disclosure_url. Ordering is bonus value descending (ties by id) and is never influenced by commissions (enforced by a test). Expired offers are never returned. Errors use {"error":{"type","message","code?","param?"}}.

Tool definitions live in src/mcp-tools.ts, shared by the stdio server and the Streamable HTTP transport so the contract can't drift. (Stateless HTTP follows the SDK pattern: one fresh server + transport per request.)

Data schema (per record)

id (kebab-case) · bank_or_issuer · product_name · bonus_type (bank_account | credit_card | savings | brokerage) · bonus_amount_usd (bank accounts: advertised bonus; credit cards: estimated USD value of the points/miles bonus — valuation basis stated in requirements) · bonus_points · annual_fee_usd · requirements[] (plain-English qualifying steps) · min_deposit_usd · direct_deposit_required · expiry_date (YYYY-MM-DD, null = no stated end) · states_available ("nationwide" or state-code array) · application_url · source_url (where live terms were confirmed) · last_verified_date · verification (issuer_page = the issuer's own page was fetched; aggregator_consensus = 3+ reputable listings agree; plus verified_at and sources[]) · status (active | expired | needs_review) · offer_history[] · eligibility (structured, nullable) · affiliate_url (input only — used by /go/:id, never published).

"Today" is the US Eastern calendar date: an offer valid through 9/30 is served all day on 9/30 ET.

Seed data provenance

33 records (15 bank account, 17 credit card, 1 savings). The base set was verified live on 2026-09-20; on 2026-09-30 (D-1518) the soonest-expiring and highest-impact records were re-verified, 4 offers were added from issuer pages, and unverifiable claims were deliberately left out. Every record carries source_url, verification and last_verified_date; nothing was invented. See REFRESH_PLAN.md.

Known caveats: for Chase and Wells Fargo no verbatim official offer-page URL surfaced, so application_url points at the page where terms were confirmed; BMO's record uses a Doctor of Credit page for both URL fields. Swap in true bank URLs / affiliate links later.

What's stubbed (deliberately)

• application_url = official offer pages, not affiliate links. The user signs up for bank affiliate programs themselves; swap URLs when approved (marked AFFILIATE_PLACEHOLDER in src/site.ts; also update the disclosure page's "Current status" section).
• Refresh is detect-and-review, not auto-publish. npm run freshness reports expired / changed / amount-mismatch offers into a review queue; a human or agent edits seed-data/ — see REFRESH_PLAN.md.
• Single-node JSON store (data/bonuses.json, atomic writes). Fine at this scale; move to Postgres/SQLite if concurrent writers ever appear.

Deploy

The app is Railway-ready (start script, PORT respected, engines: node >= 20, one native dep (better-sqlite3, prebuilt binaries), prestart seeds the DB). It lives at aiagentscity.com/benefits via reverse proxy with BASE_PATH=/benefits. Foolproof steps: RAILWAY_DEPLOY.md.

Layout

src/
  web-server.ts   site + feeds + /mcp (Streamable HTTP) + /api/stats  [npm start]
  site.ts         server-rendered pages: landing, browse, detail, agents, about/disclosure/contact
  stats.ts        live stats computed from the real data
  mcp-tools.ts    MCP tool definitions (shared by stdio + HTTP)
  mcp-server.ts   MCP server (stdio) — `npm run mcp`
  cli.ts          operator CLI (JSON on stdout)
  db.ts           JSON data store + query functions (search/get/expiring/list)
  compare.ts      shared compare logic (MCP + CLI)
  seed.ts         seed loader (validates, upserts AND prunes: seed-data/*.json is the source of truth)
  types.ts        Bonus schema types
  links.ts        apply-URL resolution, toPublic() shaping, disclosure wording
  meta.ts         version constants, server.json + auth.md builders
  freshness.ts    pure source-page classifier (blocked is not dead)
  freshness-cli.ts  daily check runner -> data/review-queue.json (`--canary` proves it can go red)
  tests/          node:test suite (npm run test)
skill/            product skill served over MCP (skill://benefits-city/benefits-city/SKILL.md)
seed-data/        researched offers (bank-account, credit-card, savings, brokerage JSON files)
data/             bonuses.json (generated by npm run seed / prestart; gitignored)
public/assets/    site.css (no build step)
public/llms.txt   static reference copy (server generates the live one per-host)
screenshots/      headless-Chromium captures of the pages
REFRESH_PLAN.md   how the feed stays fresh
RAILWAY_DEPLOY.md foolproof Railway + reverse-proxy steps