aeo-validator-service

Local HTTP smoke validator for AEO and ten other recognised Kinetic Gain Suite document kinds. It sniffs a *_version field, runs limited structural checks, computes a legacy JSON hash, and compares caller-triggered re-checks. The fourth layer of the AEO Reference Stack is a reference component, not a hosted trust decision service.

1. SDKs       aeo-sdk-python / -typescript / -rust / -go / -swift
2. CLI        aeo-cli
3. Crawler    aeo-crawler
4. Validator service   <- this repo

Why an HTTP service instead of just the CLI

The CLI answers "does this document pass its checks right now?" This local HTTP reference adds three things for experimentation:

1. HTTP for non-Python services. The CLI is Python-only. The service is a curl away.
2. Drift across manual checks. Hash a vendor's AEO document, re-check it later, and identify changed top-level fields.
3. Process-local watches. A watch holds a bounded history for comparison while this process runs. There is no scheduler, durable store, or alert delivery.

Install

pip install aeo-validator-service
aeo-validator-service          # binds 127.0.0.1:8091

Python 3.11+. Runtime deps: fastapi, httpx, pydantic, uvicorn. Remote fetching is disabled until AEO_FETCH_ALLOWED_HOSTS names exact vendor hostnames. For example, set AEO_FETCH_ALLOWED_HOSTS=acme.example before starting the service. URLs must use HTTPS on port 443, cannot redirect, and cannot carry credentials or query parameters. DNS is checked for non-public addresses before each fetch; a network egress policy is still needed to close DNS rebinding at the actual connection.

All endpoints are unauthenticated. Keep the process on loopback for local development. Do not expose it on a public network or use it for buyer authorization. A hosted service also needs authenticated callers, tenant isolation, network egress enforcement, rate limits, durable watch and audit state, and an operator runbook.

Endpoints

Supported specs

The validator sniffs the spec kind from the top-level *_version field — the same trick the unified visualizer uses. Eleven specs auto-detected:

For all eleven it checks for a nonblank version field. Additional structural smoke checks currently cover AEO, agent cards, tool cards, incident cards, and decision cards. The other six kinds receive the version check only. The service also rejects unknown or ambiguous kinds. A watch's optional spec_hint must match the detected kind.

These are examples of the limited checks:

• Universal checks — version field present, non-blank
• Spec-specific smoke checks — AEO entity has id + type + name; agent-card has agent_id + capabilities; decision-card with approved-with-conditions requires non-empty conditions[]; etc.

valid: true means only these smoke checks passed. It does not prove schema conformance, source identity, vendor claims, signature validity, buyer approval, or permission to act. Use the corresponding specification and a trusted signature/authority workflow when those assurances matter.

Drift report

{
  "url": "https://acme.example/.well-known/aeo.json",
  "drifted": true,
  "spec_changed": false,
  "became_invalid": false,
  "became_valid": false,
  "content_hash_before": "sha256:9a3f...",
  "content_hash_after":  "sha256:b7d1...",
  "added_fields":   ["claims"],
  "removed_fields": [],
  "changed_fields": ["entity"],
  "before_issues":  0,
  "after_issues":   0
}

A drift is any of: hash changed, spec kind changed, validity flipped, or top-level field set changed. Webhooks-on-drift are an obvious follow-up (PR welcome).

Quick start

# One-shot validation:
# Start the service with AEO_FETCH_ALLOWED_HOSTS=acme.example first.
curl -X POST http://localhost:8091/validate/by-url \
  -H 'Content-Type: application/json' \
  -d '{"url": "https://acme.example/.well-known/aeo.json", "include_body": true}'

# Process-local watch:
curl -X POST http://localhost:8091/watches \
  -H 'Content-Type: application/json' \
  -d '{"url": "https://acme.example/.well-known/aeo.json"}'
# -> {"watch_id": "a1b2c3", ...}

# Trigger a re-check while the same process is still running:
curl -X POST http://localhost:8091/watches/a1b2c3/recheck

Hashing convention

content_hash is sha256:<hex> over Python sorted-key, compact JSON, with default ASCII escaping. It matches the legacy hash in procurement-decision-api for the same parsed JSON values. It is not the versioned RFC 8785 JCS hash used by hash-attestation-rs v0.2 or procurement's document_hashes[]. Do not compare these hash profiles or treat a hash as publisher authentication.

Fetched JSON rejects duplicate object keys and non-finite numbers. A fetch is capped at 2 MiB while streaming. The 16-watch limit and 20-result history bound limit local memory use; all watch data is lost on restart. Watch API responses omit document bodies. The optional audit-stream event contains the URL and document hash, and its delivery is best effort.

Tests

pip install -e ".[dev]"
ruff check src tests && ruff format --check src tests
mypy src
pytest -v

Test fixtures use httpx.MockTransport so no vendor URL is fetched. CI matrix Python 3.11 / 3.12 / 3.13. Local tests do not prove hosted egress, authentication, persistence, or an operator rollback.

Related in this ecosystem

• aeo-protocol-spec — the spec this service validates.
• aeo-cli · aeo-crawler — layers 2 and 3 of the AEO Reference Stack.
• procurement-decision-api — its legacy hash matches this service's hash for the same parsed JSON values. Its versioned JCS hash for signed documents is a different profile.
• More at kineticgain.com.

License

MIT. See LICENSE.