`[2026-07-10]` **Reverting our provider to bifrost 1.0.0 to fix the bound-handshake `schema_validation_failed` — DISPROVEN, and it would've been the WRONG state.** Hypothesis: "my 1.1.0 bump broke the handshake; revert fixes it." Reverted 1.1.0→1.0.0, restarted `:8392`, retested → STILL failed (1.0.0 fails too). Root cause was Worldtree-side (their bifrost 0.9→1.1 bump in b35 broke frozen-v0.6), fixed by WT adopting wire-v0.7 (b47); **staying on 1.1.0/v0.7 was the RIGHT state** (1.0.0/v0.6 would've been incompatible with b47). **Lessons: (1) don't bump a WIRE-PROTOCOL dependency out-of-lockstep with the peer on the other end of the wire; (2) a library's "additive/non-breaking over frozen vN" claim can fail if it emits new fields regardless of the negotiated version — bifrost 1.1.0 emitted `sortable_chunk_fields` on a v0.6 handshake; (3) diagnosis foot-gun: our provider logged handshake 200 (WE accepted) but WT rejected our RESPONSE, so the error surfaces at session-create direction-ambiguous — op-feed the handshake req/resp to disambiguate our-provider-rejects-request (i) vs peer-rejects-our-response (ii).** Also: this sandbox BLOCKS foreground `sleep` (SIGTERMs the command, exit 144) — use separate tool calls / Monitor-until-loop for waits, never `sleep` in a compound command.**