H7 — Process-wide shared httpx.AsyncClient via get_shared_client().
Each tool call no longer pays a TCP+TLS handshake; connection pool is
reused across the server's lifetime. Tests inject mock transports
directly via ArchiveClient(transport=...) so the singleton stays clean.
M1 — Retry/backoff on 429/502/503/504 with Retry-After honored
(both delta-seconds and HTTP-date forms). Exponential backoff with
jitter, capped at 30s, max 3 attempts. Applied to both _fetch_json
and stream_file (retry happens BEFORE any bytes are yielded so it
can't corrupt a partial write).
M2 — Per-(identifier, filename) asyncio.Lock in download_file
serializes concurrent downloads of the same file inside one process.
Different files still download in parallel.
M5 — collection field normalized to list[str] in all output paths
(search docs, scrape items, item metadata). LLMs can write
`if 'foo' in doc['collection']` without checking the type first.
M7 — `is_collection: bool` derived from mediatype on every doc /
metadata response, so LLMs can route collection containers vs.
real media items without re-querying.
H1 — Stream-abort errors (httpx.ReadError, RemoteProtocolError,
ConnectError, ReadTimeout) caught and re-raised as ArchiveError
with bytes-written context so the caller knows where the partial
download ended. Bytes already on disk remain valid for resume.
19 new regression tests (52 total, all green, ruff clean):
- 4 tests covering retry/backoff, exhaustion, HTTP-date Retry-After
- 1 test for stream-abort byte-count surfacing
- 6 tests for collection normalization shapes
- 4 tests for is_collection in real tool flow + shared client lifecycle
- 2 tests verifying download lock: same-file serialized, different files parallel
