SPAN CHAIN
Logs you can verify.
Runs you can replay.
Span Chain is the audit layer. Every LLM call, tool use, and decision
your agent makes lands in an append-only, SHA-256 hash-chained ledger —
then becomes raw material for deterministic replay, structural
comparison, and evals. Elixir/OTP underneath; OpenTelemetry on the wire.
HOW IT WORKS — FROM SPAN TO RECORD IN THREE STEPS
01 · INGEST
Every span arrives via OTLP HTTP.
Standard OpenTelemetry wire format. Python + TypeScript SDKs included. The SDK stays dumb — all logic lives in the backend.
02 · CHAIN
SHA-256 hash links to the previous.
Each entry includes the hash of the one before it. Append-only — historic spans can be read but never edited or removed without detection.
03 · VERIFY
verify_ledger catches any tampered entry.
Instant chain re-walk. A single modified byte anywhere in history fails verification. Detection is not best-effort — it's mathematical.