Module ids 

Canonical stable identifiers for sessions, forks, events, and transcript messages.

Newly minted identities use RFC 9562 UUIDv7 — the 48 most-significant bits are the Unix-epoch timestamp in milliseconds (monotonic per process, sort- equivalent to creation order), the next 4 bits are the version, the next 2 bits are the variant, and the remaining 62 bits are random.

Identity is implemented in pure Rust (no uuid crate, no rand crate) so F1 stays within the protocol crate’s locked dependency set. The PRNG is a splitmix64 seeded from system time + process id + an atomic counter, so on any single platform a sequence of mints produced at distinct timestamps is unique with overwhelming probability and still satisfies the RFC’s “unpredictable” requirement (the 62 random bits are sufficient for the version-7 collision domain and there is no security claim at stake here; the F1 deliverable explicitly says “stable identity, not security”).

Producers (the engine loop) still pick constant message ids (final, forced-stop, graceful-summary, …) and seq independently of the database row sequence. The id helpers below derive every message identity from the persisted row sequence at the storage boundary, so every message gets a <kind>-<row_seq> identity and React keys stay unique and stable (per the rendering-lists contract).

Functions

assistant_message_id

Canonical id for an assistant message at row_seq.

is_canonical_uuid_v7

Predicate — cheaply identifies any RFC 9562 v7 UUID string. Used by the storage boundary to decide whether an incoming identity is the new canonical shape (mint-vs-rewrite).

message_id

Build the canonical id for a transcript message at row_seq. Independent of the payload-supplied id so two rows whose producers both chose the same constant id are still uniquely keyed by their persisted sequence.

tool_call_origin_id

Canonical id for a ToolCallStarted origin row. This is the row-level identity an awaited engine dispatch consults; the protocol event itself still carries a seq-derived display id, but the durable record uses this shape so a tool result can deterministically find its origin at replay time.

tool_result_id

Canonical id for a TranscriptMessage carried inside a tool result.

uuid_v7

Mint a UUIDv7 string. Output format is the canonical hyphenated 36-character lowercase form, equivalent to a UUID-printable BNF: 8-4-4-4-12 hex with version=7 and variant=8/9/a/b.