The 24 existing fuzz targets cover the delta, artifact, sync-parser and logstore layers, but not the two CLI-layer modules that consume bytes an untrusted remote peer chose. `sync_parsers_adversarial` covers the layer above; the HTTP framing itself was unfuzzed. These are the last two wire surfaces on the release bar, and they are what a hostile peer reaches first.

What landed:

- `src/transport_fuzz.zig` — `frameGarbage`, registered as `transport_frame_garbage`. Client-side §4/§4.1 framing and redirect policy: the round-trip law (whatever `frame` produces, `unframe` returns exactly those plaintext bytes), mutation of framed containers (bit damage never survives as *different* plaintext — it either fails the container's Adler-32/zlib checks or, in the length-field range the §4.1 compression-length erratum makes a capacity bound, decodes back to the same bytes), and garbage `Location` headers through `resolveRedirect`. Totality is the asserted contract: every input yields a value whose postconditions hold or a declared member of `TransportError`.

- `src/serve_fuzz.zig` — `requestGarbage`, registered as `serve_request_garbage`. Server-side HTTP request path: raw bytes into `std.http.Server.receiveHead`, then `handleHttpRequest`'s dispatch (`classifyXfer` -> body read -> responder -> reply framing). It does not re-feed `handleXfer` in isolation — that decoding is already fuzzed twice — it reaches it only as the tail of a full-path dispatch, which is the point. Asserted contract: any `receiveHead` error is a clean rejection, `handleHttpRequest` returns void, and any produced response begins with an HTTP/1.1 status line.

- `src/serve.zig`: `driveHttp` becomes `pub`. It is the request-path seam two callers need and neither should reimplement — the §4 smoke tests and this fuzz target. In-memory reader/writer on both sides, so the target binds no port and cannot flake in CI.

- `src/fuzz_tests.zig`: both targets registered in the `targets` table, and `targets` becomes `pub` for a new structural registration pin. An unregistered target compiles, passes review, and is then never run by any invocation; the pin asserts every target the release bar names is actually reachable from the runner, so the registration cannot rot.

- `src/dst.zig`: aggregates both new files plus `fuzz_tests.zig` into `zig build test`. This root is the one that reaches serve.zig and transport.zig relatively while carrying the `zit` dep those two import; `zig build fuzz` has no test step, so it is also the only place the registration pin can run.

No bug found, so no fix and no pinned-seed regression in this commit — both surfaces held over the seeded runs below. The targets are the standing check, not a one-time sweep.

Test evidence (this worktree, after `fossil update` absorbed the sibling `zit open` commit 5ba418801d and its 8 modified files):

- `zig build fuzz -- transport_frame_garbage --seed 1 --rounds 2000` — clean, no crash/leak/UB. - `zig build fuzz -- serve_request_garbage --seed 1 --rounds 2000` — clean, no crash/leak/UB. - `zig build test` — green, including the new registration pin and the fixed-seed smoke tests at the foot of both new files. - `zig build` and `zig fmt --check .` — green.

No borrowed technique in this change. check-in: cec4afaf89 user: dmestas tags: release-0.1