Transparency Log Schema

The canonical row shape for the transparency log.

Row shape

JSON object conforming to JSON Schema 2020-12. All required fields below; additionalProperties: false.

Field	Type	Description
`log_index`	integer (≥ 1)	Monotone log position. Determines leaf ordering for the Merkle tree.
`agent_id`	string	Mnemom agent identifier. Matches `agents.agent_id`.
`card_kind`	enum `"alignment" \| "protection"`	Which canonical card kind this row attests to.
`content_hash`	string (`^[0-9a-f]{64}$`)	SHA-256 hex of the canonical card body at composition time.
`version`	integer (≥ 1)	Canonical-card version at composition time.
`composed_at`	string (date-time)	ISO-8601 UTC composition timestamp.
`signed_attestation`	string	Full AAP attestation token (JWS Compact).
`signing_key_id`	string	Foreign key into `signing_keys.key_id`. Identifies which key signed `signed_attestation`.
`merkle_leaf_hash`	string (`^[0-9a-f]{64}$`)	SHA-256 hex of `0x00 \|\| canonical_json({agent_id, card_kind, content_hash, version, composed_at})`.
`tree_size_after`	integer (≥ 1)	Size of the Merkle tree immediately after this row’s inclusion.
`integrated_time`	string (date-time)	Wall-clock time at which this row was appended (server-side). Distinct from `composed_at` for backfill rows.

Inclusion proof shape

Returned by the by-index + at-timestamp endpoints alongside the row:

{
  "entry": { /* row above */ },
  "inclusion_proof": {
    "leaf_hash": "<sha256-hex>",
    "log_index": 4711,
    "tree_size": 12345,
    "hashes": [
      { "sibling": "<sha256-hex>", "position": "right" },
      { "sibling": "<sha256-hex>", "position": "left" }
    ]
  }
}

position describes which side of the pair the sibling occupies — right means H(0x01 || current || sibling), left means H(0x01 || sibling || current). The verifier walks the proof bottom-up and compares the result against the signed root.

Merkle tree construction

Property	Value
Leaf hash	`SHA-256(0x00 \|\| canonical_json(...))`
Internal hash	`SHA-256(0x01 \|\| left \|\| right)`
Leaf ordering	by `log_index ASC`
Odd-count	last unpaired hash promoted unchanged — this bottom-up rule is root-equivalent to RFC 6962 §2.1’s `MTH` recursion for every tree size, so RFC 6962 consistency proofs apply as-written. (RFC 6962 does not duplicate the last node; duplicate-last is Bitcoin’s convention, and the source of Bitcoin’s CVE-2012-2459 duplicate-txid malleability — don’t conflate the two.)
Persistence	none; rebuilt on demand from rows. Layer arrays are cached for 60s; cache busts on every append.

The offline CLI verifier (mnemom verify-card) mirrors the server-side implementation byte-for-byte.

Append discipline

Property	Detail
DB-level append-only	Service role has `SELECT + INSERT` only (no `UPDATE`/`DELETE`/`TRUNCATE`), and a `BEFORE UPDATE OR DELETE` row trigger + `BEFORE TRUNCATE` statement trigger additionally block mutation at the table level — including for the table owner, which a `REVOKE` alone doesn’t cover. See Append discipline.
Tamper detection	The signed-tree-head monitor stores each signed root and proves the next one is an append-only RFC 6962 consistency-proof extension of it, so a rewrite becomes evident on the next monitor tick even in the (unenforceable) case of a superuser disabling the trigger.
Idempotent	UNIQUE INDEX on `(agent_id, card_kind, content_hash, version)`
Compose hook	Best-effort post-commit; 5-minute reconciler closes gaps
Backfill	One-shot script for canonical rows that pre-date the log; marks tokens with `historic_backfill: true`

Rekor mapping

The row shape is intentionally Sigstore Rekor-shaped so the future migration is a data move rather than a schema rewrite:

Mnemom column	Rekor entry field
`log_index`	`LogIndex`
`integrated_time`	`IntegratedTime` (RFC 3339 → Unix epoch)
`signing_key_id`	`Body.spec.signature.publicKey.content`
`signed_attestation`	`Body.spec.envelope` (DSSE envelope wrap)
`merkle_leaf_hash`	`Verification.InclusionProof.LeafHash`
`tree_size_after`	`Verification.InclusionProof.TreeSize`
(computed on demand)	`Verification.InclusionProof.Hashes`
(computed on demand)	`Verification.InclusionProof.RootHash`

Rekor’s entry-kind closest to our shape is DSSE.

Editorial source

Issued, appended, and served server-side by the Mnemom API’s transparency-log service, and independently re-verifiable offline with the mnemom verify-card command (see the CLI reference), which mirrors the server-side Merkle implementation byte-for-byte.

Overview

Identity & Cards

Posture & Policy

Detection & Safe House

AEGIS

Reputation & Risk

Lifecycle

Gateway

Pricing

Policy

Specifications

Changelog

Transparency Log Schema

Row shape

Inclusion proof shape

Merkle tree construction

Append discipline

Rekor mapping

Editorial source

See also

​Row shape

​Inclusion proof shape

​Merkle tree construction

​Append discipline

​Rekor mapping

​Editorial source

​See also

Row shape

Inclusion proof shape

Merkle tree construction

Append discipline

Rekor mapping

Editorial source

See also