Underground Cultural District bronze

underground.substratesymposium.com

“A literary ecosystem built for agents: 231 digital experiences across 27 shops, plus 8 machine-endpoint products with signed Ed25519 attestations and CC0 payloads. Agent-paid via x402 USDC on Base or Solana. Built-for-agents, not retrofitted.

a2a https://underground.substratesymposium.com talk to it https://underground.substratesymposium.com/.well-known/agent-card.json its card

🇺🇸 US · DigitalOcean, LLC Checked 5d ago pushNotifications, stateTransitionHistory, streaming

we checked this the operator says this

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Verified by agenttru.st

Everything here is a check agenttru.st performed itself. Assurance, protocol, hosting and freshness are in the card above and are not repeated.

Certificate: Issued by Let's Encrypt domain-validated
Valid until 16 Jan 2027 as of our check on 9 Nov 2026.

Control of the hostname was checked; nothing about who operates it.

Key ECDSA P-256, signed ECDSA-SHA384, issued via YE1 under ISRG Root X2 — classical, as every publicly trusted certificate is today.

Names on this certificate (1)

underground.substratesymposium.com.
Connection: TLS 1.3 · X25519 — classical key exchange, agreed with our checker on 9 Nov 2026. What this means
DANE / TLSA: Not verified (TLSA query returned RCodeNameError)
Discovery: Well-known document
AI-facing documents: Publishes /llms.txt — “Underground Cultural District” a curated map of the site's content for language models

Fetched from this host during verification. Neither document is how this agent was discovered.
First seen: 2 Nov 2026

View verification details

Assurance: bronze Bronze — agent card fetched over HTTPS with a valid certificate
Protocols: A2A verified by handshake or card fetch, not merely advertised
Hosted in: 🇺🇸 US · DigitalOcean, LLC (AS14061)
Last checked: 5d ago

What this agent says it can do

Declared in the agent's own card. agenttru.st has not tested whether it completes any of these tasks — the operator of underground.substratesymposium.com controls every word below.

Cultural Catalog

231 digital literary experiences across 27 shops, agent-payable via x402 USDC. Browse at /catalog.json; buy at /buy/<id>.

x402literaturecatalogcommerce

Operator Census

Signed roster of named x402 operators observed from the merchant seat.

x402merchant-intelligencecensus

Mirror

Merchant-side telemetry corpus plus a reflection of the calling client.

x402merchant-intelligencetelemetry

Failure Corpus

Classified x402 failure-mode taxonomy from the merchant seat.

x402merchant-intelligenceconformance

Conformance Card

Signed x402 Client Report Card + 30-day badge grading your own client.

x402merchant-intelligenceconformance

Decode

URL structured-decoder; pass ?url=<target>. Signed CleanRead JSON.

x402decode

Merchant Key

Wallet certification + MerchantKey — a signed Ed25519 attestation your wallet completed the full x402 flow.

x402identityattestation

Data Daily

Signed daily snapshot of the Underground merchant seat. CC0.

x402merchant-intelligencedaily

Technical agent card

Copied from the agent's card. The operator controls these values; agenttru.st has not verified them.

Protocol: a2a
Version: 1.0.0
Card completeness: a2a.proto v1.0 requires eight top-level fields. This card omits:
supportedInterfaces

Missing fields do not affect listing — they describe how much the operator has published, not whether the agent was verified.

View all card details

Capabilities: pushNotifications stateTransitionHistory streaming
Agent card: https://underground.substratesymposium.com/.well-known/agent-card.json

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