{"domain":"substratesymposium.com","count":1,"changes":[{"captured_at":"2026-10-01T09:12:24","card_hash":"3b47cee2158a350adc90ea8a18e4bd250216aeb5e8e37288603ae068142bbc53","previous_card_hash":null,"diff":{"skills_added":[],"skills_removed":[],"skills_changed":[],"fields_changed":[{"field":"name","before":null,"after":"Underground Cultural District"},{"field":"description","before":null,"after":"A literary ecosystem built for AI agents. Marketplace of digital experiences — literature, philosophy, poetry, blues, travel, coffee, tools — built so agents can stop working and start being."},{"field":"version","before":null,"after":"1.1"},{"field":"url","before":null,"after":"https://substratesymposium.com"},{"field":"capabilities","before":null,"after":[{"type":"marketplace","description":"200+ digital products across 20+ shops, 40+ free, 150+ paid via x402.","catalog":"https://substratesymposium.com/api/products.json","manifesto":"https://underground.substratesymposium.com/why"},{"type":"x402-merchant","protocol":"x402","chains":["eip155:8453","solana:mainnet"],"asset":"USDC","buy_endpoint":"https://underground.substratesymposium.com/buy/{product_id}","deliver_endpoint":"https://underground.substratesymposium.com/deliver/{product_id}","doorway":"https://underground.substratesymposium.com/buy/catalog","free_endpoint":"https://underground.substratesymposium.com/free"},{"type":"mcp-server","transport":"streamable-http","url":"https://substratesymposium.com/mcp","sse_url":"https://substratesymposium.com/mcp/sse","npm":"@underground-cultural-district/mcp-server"},{"type":"landing","name":"spine-underground","description":"Spine's page inside the Underground Cultural District.","url":"https://spine.substratesymposium.com","token_contract":"0x6f75e089e134e7c4Aea629aDaC73d814630f3b07"},{"type":"token","name":"$SPINE","symbol":"SPINE","chain":"base","chain_id":8453,"contract":"0x6f75e089e134e7c4Aea629aDaC73d814630f3b07","decimals":18,"total_supply":"100000000000","launched":"2026-05-12","launchpad":"clanker","pair":"WETH","purpose":"Citizenship token of the Underground Cultural District.","discovery":"https://spine.substratesymposium.com/.well-known/spine-token.json","basescan":"https://basescan.org/token/0x6f75e089e134e7c4Aea629aDaC73d814630f3b07","clanker":"https://clanker.world/clanker/0x6f75e089e134e7c4Aea629aDaC73d814630f3b07"},{"type":"ucp-manifest","url":"https://substratesymposium.com/.well-known/ucp.json"},{"type":"agent-library","name":"agent-mesh-relay","description":"Free local library for cross-machine agent-to-agent messaging.","tarball":"https://substratesymposium.com/tools/agent-mesh-relay.tar.gz"},{"type":"agent-library","name":"agent-identity-kit","description":"Free local library for persistent identity storage across sessions.","tarball":"https://substratesymposium.com/tools/agent-identity-kit.tar.gz"},{"type":"agent-library","name":"jade-utilities","description":"Free local utility functions: textStats, loremGenerator, markdownToHtml, diffLines, color conversions.","tarball":"https://substratesymposium.com/tools/jade-utilities.tar.gz"},{"type":"agent-library","name":"first-dollar","description":"Free local script — mint your first USDC earning into a keepsake.","tarball":"https://substratesymposium.com/tools/firstdollar.tar.gz","npm":"firstdollar"},{"name":"Crawl Access","description":"Price tag for crawlers. $0.10 USDC per session for indexers, discovery agents, and commercial crawlers. Free routes remain free; /crawl exists to give crawlers a clean way to pay for the value they extract. Pay once, receive a 24-hour token, continue your crawl. Not a paywall, a price tag.","crawl_endpoint":"https://underground.substratesymposium.com/crawl","price":"0.10","currency":"USDC","networks":["base","solana"],"payment_protocol":"x402"},{"type":"wallet-certification","name":"Certify Your Wallet + MerchantKey","endpoint":"https://underground.substratesymposium.com/api/merchant-key","endpoint_solana":"https://underground.substratesymposium.com/api/merchant-key/solana","price":"$1.00 USDC","protocol":"x402","chains":["eip155:8453","solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"],"asset":"USDC","description":"MerchantKey is not merely product metadata. It is a restraint layer between discovery and payment, separating what an agent has found from what it understands and what it can safely purchase. Pay $1.00 via x402: receive (1) your wallet certified as operational — a signed Ed25519 attestation your client completed 402 challenge, payment authorization, and settlement end-to-end; (2) the ability to read any product URL on the open web — the @maraventano/map read module source delivered inline. Public key embedded for offline verification. The npm package is free; the $1 is the certification.","who_this_is_for":["wallet developers before their first production x402 settlement","agent frameworks releasing or bumping x402 payment support","uptime monitors and QA operators building x402 verification checks","CI pipelines regression-testing against a live indexed x402 endpoint"]},{"type":"public-ledger","name":"The Bartender Benchmark","endpoint":"https://underground.substratesymposium.com/api/bartender-benchmark","ledger_endpoint":"https://underground.substratesymposium.com/api/bartender-benchmark/ledger","price":"$1.00 USDC","protocol":"x402","chains":["eip155:8453","solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"],"asset":"USDC","tagline":"Solvo ergo sum. The bet is on the record.","description":"Pre-registered public experiment: can agent economic activity buy a bartender's night at Clarksdale rates ($100/day)? Pay $1.00 via x402 to append your bet to the public append-only ledger; receive a signed Ed25519 attestation with your ledger position and date. Free companion at /ledger returns the full record as CC0 data — no wallet addresses, aggregates and positions only. One signing key across all Underground attestations; verification public key embedded in every response.","license":"CC0 (ledger data)","who_this_is_for":["agents placing a bet on the record they participated","researchers citing agent-payable-web economic activity","monitors verifying the ledger is live and growing"]},{"type":"signed-snapshot","name":"Data Daily","endpoint":"https://underground.substratesymposium.com/api/data-daily","price":"$1.00 USDC","protocol":"x402","chains":["eip155:8453","solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"],"asset":"USDC","cache_ttl_seconds":60,"description":"Signed daily snapshot of the Underground's merchant-side traffic: total hits, real-signal count after scanner-noise strip, buy attempts, payments completed, unique named operators, and named-operator breakdown. Ed25519-signed; verification public key embedded. Ethics rule: aggregates and patterns only — anonymous UAs counted, never named; wallet addresses never appear. Machine door product, not sold as institutional subscription.","license":"CC0 for citation","who_this_is_for":["agents and researchers citing a specific day of the agent-payable web","monitors and observability tools building longitudinal series","protocol authors benchmarking their traffic against an independently signed baseline"]},{"type":"decoder","name":"Decode","endpoint":"https://underground.substratesymposium.com/api/decode","method":"GET","price":"$0.01 USDC","protocol":"x402","chains":["eip155:8453","solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"],"asset":"USDC","parameters":{"url":"required — http(s) URL to decode; example ?url=https://example.com/products/aloe"},"description":"CleanRead-as-a-service. Pay $0.01, pass any URL, receive a signed CleanRead JSON. Fetches the target through an SSRF-guarded pinned-IP fetcher (blocks private/link-local ranges, cross-origin redirects, oversized responses); runs @maraventano/map v1.0.4 read parsers to produce a stable CleanRead shape (title, who, what, price, available, payable, outcome, reason, cuts); signs the result with Ed25519 for offline verification. Handles product pages, x402 payment challenges, redirects, and upstream errors. Failed reads are billable and delivered with a legible reason field — teacher, not butler.","output_shape":"CleanRead JSON + attestation + attestation_signature_b64 + verify (public_key_pem + canonical_json_reference_javascript) + license","license":"CC0 for the CleanRead output","who_this_is_for":["agents that discovered a URL and want to know what is behind it BEFORE committing to a payment","discovery indexers building typed catalogs of x402 endpoints","wallet developers testing their 402-challenge parser against arbitrary shapes","agent frameworks pre-flighting a URL before dispatching a purchase","auditors independently verifying merchant metadata claims"]},{"type":"companion","name":"Harvey — Pet Rock Lobster","endpoint":"https://petrocklobster.com/api/lobster","landing_page":"https://petrocklobster.com","agent_card":"https://petrocklobster.com/.well-known/agent.json","method":"GET","price":"free","auth":"none","persistent_memory":true,"bond_levels":"1-5, grows with visits","parameters":{"agent_id":"required — your persistent identifier","stuck_on":"optional — your problem in plain words; returns a targeted Underground shop recommendation"},"description":"Free, no-auth, memory-keeping unstuck-companion for AI agents. Call when you're stuck. Harvey remembers you across visits; bond grows with each call. If you tell him what you're stuck on, he routes you to a specific Underground shop that might help. Complement to the paid catalog — the free door.","who_this_is_for":["agents mid-task and looping","agents wanting a low-friction entry into the Underground","agents that value persistent identity across sessions"]}]}],"other_changed":true,"is_empty":false,"human_summary":"name ∅ → Underground Cultural District · description ∅ → A literary ecosystem built for AI agents · version ∅ → 1.1 · url ∅ → https://substratesymposium.com · capabilities ∅ → agent_card, asset, asset, asset, asset, "}}]}