Internal rail inbound callback
Internal-only inbound rail callback guarded by the X-Internal-Callback shared secret. Not a client API surface.
Headers
Internal callback shared secret
Body
SHA-256 hex digest of the referenced payload bytes
"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
Opaque reference to the payload bytes held in the server-side resolver
Timestamp the mesh received the rail message, RFC3339 UTC
"2026-06-14T12:00:00Z"
Originating rail/source identifier of the inbound message
Optional channel discriminator routing the message to a handler
Forwarded transport headers (e.g. Idempotency-Key), used for idempotency and routing
Optional base64-encoded payload bytes; staged server-side after hash verification
Response
OK
Outcome of processing the inbound message (e.g. ACCEPTED, QUARANTINED)
"ACCEPTED"
Safe-to-return human-readable explanation of the decision
UUID of the persisted message record when the message was accepted
"550e8400-e29b-41d4-a716-446655440002"
UUID of the quarantine record when the message was quarantined
"550e8400-e29b-41d4-a716-446655440003"

