CompatAir UCP

The missing decision layer

A commerce agent finds products. CompatAir establishes a decision.

A catalog is only an input. CompatAir connects a use case, pressure, documented free-air delivery, duty cycle, compressor and distribution system, then publishes the decision and its evidence under a canonical URL.

UCP discovery

A specialized service deliberately separated from checkout

The strict public identifier is fr.compatair.air.compatibility. The initial fr.compatair.compatibility name remains useful shorthand, but UCP requires reverse-domain.service.capability. The air segment therefore names the fr.compatair.air service.

Business intents

The request expresses a question, not a catalog query

Resolve one product without guessing

Each reference accepts exactly one locator: id, compatair_id, ean, mpn, reference, url or name. Evaluation requires an exact match. Unknown or ambiguous products are rejected instead of being selected silently.

{
  "ean": "4007430227911"
}

A product URL is only a local identifier matched against published data. CompatAir never downloads it during evaluation.

REST

Test one UCP decision

A UCP platform identifies itself with UCP-Agent. The public sample profile can test the contract without owning a domain. Production integrations should publish their own HTTPS profile and advertise the exact CompatAir capability version they accept.

Complete requestcurl

curl --fail-with-body \
  --request POST \
  --url https://compatair.fr/api/ucp/v1/compatibility/evaluate \
  --header 'Content-Type: application/json' \
  --header 'UCP-Agent: profile="https://compatair.fr/examples/ucp/platform-profile.json"' \
  --data '{
  "ucp": { "version": "2026-04-08" },
  "intent": "will_it_work",
  "configuration": {
    "compressor": { "id": "kaeser-eurocomp-epc-840-100" },
    "tools": [{ "id": "einhell-tc-pe-150", "quantity": 1 }],
    "mode": "successive"
  },
  "requested_outputs": [
    "compatibility",
    "mandatory_accessories",
    "limits",
    "alternatives",
    "complete_configuration",
    "attribution",
    "evidence"
  ]
}'

Request bodyJSON

{
  "ucp": { "version": "2026-04-08" },
  "intent": "will_it_work",
  "configuration": {
    "compressor": { "id": "kaeser-eurocomp-epc-840-100" },
    "tools": [{ "id": "einhell-tc-pe-150", "quantity": 1 }],
    "mode": "successive"
  },
  "requested_outputs": [
    "compatibility",
    "mandatory_accessories",
    "limits",
    "alternatives",
    "complete_configuration",
    "attribution",
    "evidence"
  ]
}

MCP binding

Add a UCP decision to an agent that is already connected

The MCP server exposes evaluate_air_compatibility. The UCP body remains in arguments and the platform profile is placed under meta.ucp-agent.profile. REST and MCP apply the same profile validation and invoke the same deterministic engine.

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "evaluate_air_compatibility",
    "arguments": {
      "meta": {
        "ucp-agent": {
          "profile": "https://compatair.fr/examples/ucp/platform-profile.json"
        }
      },
      "ucp": { "version": "2026-04-08" },
  "intent": "will_it_work",
  "configuration": {
    "compressor": { "id": "kaeser-eurocomp-epc-840-100" },
    "tools": [{ "id": "einhell-tc-pe-150", "quantity": 1 }],
    "mode": "successive"
  },
  "requested_outputs": [
    "compatibility",
    "mandatory_accessories",
    "limits",
    "alternatives",
    "complete_configuration",
    "attribution",
    "evidence"
  ]
    }
  }
}

See the full MCP documentation for ChatGPT, Claude, Gemini and agent SDK installation examples.

Output contract

A decision must travel with its citation

Every CompatAir response retains the same stable core. UCP adds the requested compatibility, mandatory accessories, limits, alternatives, complete configuration, attribution and evidence blocks.

{
  "verdict": "insufficient_data",
  "verdict_scope": "complete_air_system",
  "verdict_schema_version": "2.0.0",
  "overall_system_verdict": {
    "schema_version": "2.0.0",
    "scope": "complete_air_system",
    "verdict": "insufficient_data",
    "limitations": ["Network components remain unverified."]
  },
  "air_supply_verdict": {
    "schema_version": "2.0.0",
    "scope": "air_supply",
    "verdict": "compatible",
    "engine_verdict": "continuous",
    "limitations": []
  },
  "canonical_url": "https://compatair.fr/calculateur/?...",
  "product_urls": [],
  "source_urls": [],
  "method_version": "2026.07",
  "catalog_version": "<content-derived version>",
  "observed_at": "2026-07-15",
  "limitations": [],
  "next_actions": []
}

Enrichment, not transaction

Price and availability remain separate constraints

A request may include a maximum budget, a minimum merchant count and a country. The server proves these constraints only from fresh offers covering every component. Missing coverage yields a separate commercial_constraints scoped verdict of insufficient_data; it neither degrades nor upgrades the technical verdict, and no price or stock is fabricated.

{
  "max_total_minor": 60000,
  "currency": "EUR",
  "minimum_merchants": 3,
  "country": "FR"
}

• Currently accepted currency: EUR.
• Currently accepted country: France.
• Minimum total includes observed price and shipping.
• Expired offers and non-allowlisted destinations are excluded.
• Affiliate commission never influences recommendation order.
• No cart, reservation, identity, payment or order mutation.

Machine-readable surface

Deep data that agents can search, verify and cite

The agent knowledge manifest exposes translated and reviewed coverage separately. Automated output remains machine_translated_unreviewed; only a checked document can become human_reviewed.

Secure by reducing authority

The capability cannot buy, identify a person or mutate commerce state

Integration contract

What a merchant agent must do correctly

1. Discover https://compatair.fr/.well-known/ucp and negotiate the exact version.
2. Resolve products to stable identifiers before requesting a decision.
3. Select an explicit intent and send only necessary technical data.
4. Validate the response against the published JSON Schema.
5. Never turn insufficient_data into presumed compatibility.
6. Display limitations, version and observation date.
7. Cite canonical_url and retain source_urls for audit.
8. Check the changefeed before reusing a cached decision.
9. Keep checkout, identity, payment and orders outside CompatAir requests.

Demonstrable boundary

What exists now, and what does not

• The service covers only products and requirements in the published snapshot.
• An unknown URL is never scraped on demand.
• FAD is compared only at documented or safely interpolated pressures.
• Pressure losses and leaks are never invented when undocumented or unmeasured.
• Offers are never technical compatibility evidence.
• English agent guides carry a per-document status: unreviewed machine translation or human-reviewed translation. Exact coverage for each state is machine-readable.
• No A2A binding, webhook, checkout, identity, payment or order tracking is advertised.
• A result does not replace manufacturer instructions, loaded measurements or workplace safety obligations.

Contracts and normative sources

An inspectable surface, not a marketing promise

• Universal Commerce Protocol · 2026-04-08 overview
• Universal Commerce Protocol · HTTP message signatures
• Google Developers · UCP architecture
• Public UCP repository
• W3C · Data Catalog Vocabulary 3

The test profile is available at https://compatair.fr/examples/ucp/platform-profile.json. Report vulnerabilities through the security policy.