[1932819331hy-debug]

Summary

 HTTP 200 with a truthy JSON primitive envelope
- TypeError -> transport retries -> RpcError
+ RpcShapeError, without retrying

Add an object-type guard before checking for result, restoring the existing unreadable-response contract. Valid results, including null, explicit RPC errors and transient transport retries keep their behavior. Only src/rpc.js and a focused regression file change.

Evidence

• Before: the new native regression suite has 14 passes / 3 failures on main 13184ff111532c172f37d54d59f00e7eea6b9a23.
  After: all 17 pass; native npm test passes 40/40.
• Independent AI-assisted review: 47/47 protocol cases pass, and four deliberately broken variants are caught by the new tests alone.
• Local composition with fix: reject unsafe schedule block counts before projection #1 passes 50/50. Both patch orders produce the same full tree; its branch and scope are unchanged.
• Node 24.22.1, native JSON decoding and injected synthetic transport only. No dependency installation or live-provider requests. Node 18/20/22, other operating systems and hosted CI remain unverified.

This is a source-backed contract repair, not completion of a separate maintainer issue. AI assistance was used for implementation, testing and review.

Merge Danger

Door: Two-way. One production guard, with no migration.

Blast Radius: RPC.

Malformed truthy primitive responses now stop immediately rather than being retried. JSON parse-error and broader retry policies are unchanged.