{"answer":"Findings from reading the changed files under `pr/`:\n\n🔴 `bug` services/proxy/src/metrics.rs:88: `values()` returns `sweep_bytes_reclaimed` then `sweep_blobs_removed` (lines 94-95), but `COUNTERS` lists `cairn_proxy_sweep_blobs_removed_total` then `cairn_proxy_sweep_bytes_reclaimed_total` (lines 51-57) — `render()`'s zip pairs each counter with the other's name, so every scrape reports bytes under the blobs-removed metric and vice versa. `docs/operations.md` tells operators to watch `cairn_proxy_sweep_bytes_reclaimed_total`, which now shows a blob count.\n\n🟠 `bug` services/proxy/src/routes/admin.rs:76: `reclaim` calls `app.sweeper.sweep(dry_run)` directly, bypassing the `running` mutex that only `Sweeper::run` (sweep.rs:82-85) takes. An on-demand sweep therefore runs concurrently with the background sweep, which is exactly the two-sweeps-over-one-directory hazard sweep.rs:10-12 says the type exists to prevent: both decide what to remove from a total the other is changing, over-evicting the store far below the ceiling.\n\n🟠 `bug` services/proxy/src/routes/admin.rs:76: the sweep handler runs `Sweeper::sweep` — a fully synchronous `std::fs` walk and unlink pass over the whole store (sweep.rs:90-149) — directly on the async runtime worker thread. A store with tens of thousands of entries blocks the executor for the whole pass, stalling every other request including `/healthz` and `/metrics`; it needs `spawn_blocking`.\n\n🟠 `bug` services/proxy/src/sweep.rs:140: `forget(&index, &gone)` runs unconditionally, including on a dry run. `gone` holds every candidate the dry run *would* remove, so `?dry_run=true` — documented as reporting \"without removing anything\" — actually deletes the index entries for those blobs, turning live cache coordinates into misses and forcing refetches for an operator who was only trying a ceiling out.\n\n🟠 `bug` services/proxy/src/sweep.rs:230: `clear_partials` unlinks every file in `incoming` with no age check, but `incoming` also holds the temp files of fetches in flight right now (`BlobStore::writer`, store.rs:171-180, writes there until commit). A sweep that lands mid-download unlinks the temp file out from under the writer; the later `fs::rename` in `BlobWriter::commit` (store.rs:259) fails with NotFound and the client's fetch fails. Needs the same `min_age` grace the blob path has.\n\n🟡 `bug` services/proxy/src/sweep.rs:164: `fs::metadata` follows symlinks, so a symlink is counted (and recursed) at its *target's* size and type, not the link's — the opposite of what the comment at lines 160-163 claims (`symlink_metadata` is what that needs). A symlinked directory is also recursed into, so a symlink cycle under the blob dir makes `collect` recurse until the stack blows.\n\n🔵 `bug` services/proxy/src/main.rs:115: tokio's `interval` completes its first tick immediately, so the loop sweeps straight away. The doc comment at main.rs:101-102 claims the first tick is one interval away precisely to stop a freshly started proxy from sweeping an empty cache — the stated behaviour and the actual behaviour are opposite (harmless today only because the store is empty at startup).\n\n🔵 `bug` services/proxy/src/sweep.rs:126: when `fs::remove_file` fails, the blob is still counted — `remaining` is decremented, `bytes`/`removed` incremented (lines 134-136) — and `forget` then deletes its index entries anyway. A sweep that cannot unlink (permissions, EBUSY) reports reclaimed bytes that are still on disk and leaves blobs on disk that nothing in the index can reach.","auth":{"mode":"api_key"},"effort":"high","elapsed_secs":100.04,"error":null,"error_kind":null,"instructions":[],"model":"z-ai/glm-5.3-flash","ok":true,"sandbox":{"backend":"macOS Seatbelt","denied_read_roots":["/Users/bart.smykla@konghq.com/Projects/github.com/smykla-skalski/benchee/subjects"],"environment":["HOME","LANG","LC_ALL","PATH","TERM","TMPDIR"],"mode":"read-only","network":"denied","protected_write_roots":["/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-OrmAJW/.git","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-OrmAJW/.afi","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-OrmAJW/.agents","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-OrmAJW/.codex","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-OrmAJW/AGENTS.md","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-OrmAJW/CLAUDE.md"],"readable_paths":["/"],"readable_roots":["/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-OrmAJW","/bin","/sbin","/usr/bin","/usr/sbin","/usr/lib","/usr/libexec","/usr/share","/System/Library","/Library/Apple","/Library/Filesystems/NetFSPlugins","/Library/Preferences","/private/etc","/private/var/db/timezone","/private/var/db/DarwinDirectory/local/recordStore.data","/private/var/select/developer_dir","/private/var/select/sh","/opt/homebrew/bin","/opt/homebrew/Cellar","/opt/homebrew/etc/gitconfig","/opt/homebrew/lib","/opt/homebrew/opt","/usr/local/bin","/Applications/Xcode.app/Contents/Developer","/Applications/Xcode.app/Contents","/Users/bart.smykla@konghq.com/.local/bin/afi"],"writable_roots":["/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/afi-sandbox-73h7YY"]},"schema_version":1,"source":"openrouter","sources":[{"auth":{"mode":"api_key"},"source":"openrouter","usage":{"cache_read_tokens":29952,"cache_write_tokens":0,"cost_usd":0.011973,"estimated_tokens":0,"input_tokens":38367,"output_tokens":499,"reasoning_tokens":10591,"requests":3,"total_tokens":79409}}],"system_prompt":{"file":null,"mode":"builtin"},"tools":["read_file","write_file","edit_file","list_dir","search_files","glob_files","run_bash","wait_background"],"usage":{"cache_read_tokens":29952,"cache_write_tokens":0,"cost_usd":0.011973,"estimated_tokens":0,"input_tokens":38367,"output_tokens":499,"reasoning_tokens":10591,"refused_by_approval":0,"refused_by_policy":0,"refused_tool_calls":0,"requests":3,"total_tokens":79409}}