zapier-user-docs/09-lookup-tree-nodes.md

9. Look up a hash on tree-node archives

Zapier search: Find Hash (tree nodes + central chain).

Middleware: GET /zapier/v1/hashes/{sha256}?includeAttached=true&includeTree=true.

Sequence (you never configure this)

1. Central chain lookup (same as chapter 6).
2. If itemized, return that seal (and attached metadata if requested).
3. If miss, middleware broadcasts verae.archive.query with kinds: ["tree", …] to every tree-node NATS server.
4. A node whose bloom filter does not contain the hash stays silent.
5. A node that holds the leaf replies on verae.archive.reply.<correlationId> with { merkleRoot, proof, leafIndex, chainSealJobId }.
6. Middleware checks the proof against the root, loads the root’s chain seal, and returns both receipts.

Reading the result in a Zap

• exists: true and itemizedOnMainChain: false — this hash was in a bulk summary.
• proofOk: true — the leaf really is under merkleRoot.
• receipts includes kind: seal (of the root) and kind: tree-leaf (the proof).
• archiveId tells you which tree node answered (for support).

If every node is silent, the hash is unknown or the archive fleet is down. The simulator flags “all archives silent” when puts were known to exist; operators should treat that as an outage, not a miss.

Zap pattern

1. Search: Find Hash (tree nodes + central chain).
2. Filter / Paths:
   • Found + itemized → treat as a first-class seal.
   • Found + not itemized → store Merkle proof + root certificate.
   • Not found → optionally Create Timestamp to itemize it now.