Reference publisher: Upgrade Agent — airline/cruise/rail upgrades MCP + ARD catalog

[mikeslone-plusgrade]

Publisher

• Organization: Upgrade Agent (built by Plusgrade, a leading travel upgrade-technology provider)
• Domain: https://www.upgradeagent.ai
• Catalog: https://www.upgradeagent.ai/.well-known/ai-catalog.json
• Identity: did:web:www.upgradeagent.ai — https://www.upgradeagent.ai/.well-known/did.json
• Documentation: https://www.upgradeagent.ai/connect

Description

Upgrade Agent is an authoritative answer engine and registry for travel upgrades and ancillaries — bid upgrades, instant upgrades, seat blockers, and premium seating across airlines, cruise lines, and rail operators (85 operators today: 65 airline, 18 cruise, 2 rail). It answers upgrade questions, checks live booking eligibility, and looks up operator programs.

Integration stack:

• MCP server (Streamable HTTP): https://www.upgradeagent.ai/api/mcp — 7 tools (upgrade Q&A, live eligibility by PNR + last name, partner lookups, search). Published in the official MCP Registry as ai.upgradeagent/upgrade-agent.
• Discovery registry (application/ai-registry+json): https://www.upgradeagent.ai/api/ard/search — natural-language search over verified resources, with explicitly-stated coverage (currently 1 publisher, 0 federated carriers — stated honestly, not inflated).
• Signed catalog: Ed25519 detached JWS over JCS (RFC 8785) per entry, anchored to did:web.

Catalog entries (4)

URN	Type	Path
urn:air:upgradeagent.ai:server:mcp	application/mcp-server-card+json	/.well-known/mcp/server-card.json
urn:air:upgradeagent.ai:registry:search	application/ai-registry+json	/api/ard/search
urn:air:upgradeagent.ai:doc:llms	text/markdown	/llms.txt
urn:air:upgradeagent.ai:dataset:partners	text/html	/partners

(All urn:air: per the ai-catalog.schema.json pattern; only spec-supported media types.)

Representative queries

• how does airline upgrade bidding work
• which airlines offer bid upgrades in Europe
• check if booking ABC123 / last name Smith is eligible for a business upgrade
• find an upgrade to business across any airline for my route
• list the airlines that offer bid upgrades

Discovery surfaces

• https://www.upgradeagent.ai/llms.txt
• https://www.upgradeagent.ai/.well-known/did.json
• https://www.upgradeagent.ai/.well-known/mcp.json
• https://www.upgradeagent.ai/.well-known/mcp/server-card.json
• https://www.upgradeagent.ai/robots.txt + /sitemap.xml

Validation (checkable)

Independent signature verification — resolves did:web, recomputes the JCS bytes, verifies every entry's Ed25519 signature:

curl -s https://www.upgradeagent.ai/.well-known/ai-catalog.json
# verified with an ARD JWS verifier -> "5 verified, 0 failed" (host + 4 entries)

A CI workflow re-runs this verifier against production on every change.

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Request: please consider listing Upgrade Agent as a reference publisher / ARD registry instance for the airline, cruise & rail upgrades and ancillaries vertical — a non-normative instance under the seven-property contract. Happy to serve as a reference implementation for the travel-upgrades vertical. Deferring to the maintainers on any normative wording.