{"answer":"Findings, verified against the checked-out code:\n\n🔴 `bug` services/proxy/src/sweep.rs:140: `forget(&index, &gone)` runs even when `dry_run` is true, so a \"report only\" dry run permanently deletes the index entries for every blob it would have removed — the blobs become unreachable cache misses and are collected as unreferenced garbage by the next real sweep, making `?dry_run=true` destructive despite the route's promise.\n\n🔴 `bug` services/proxy/src/sweep.rs:102: `sort_by_key(|c| c.age)` sorts ascending, putting the *youngest* blobs first, so the eviction loop removes the most recently fetched blobs first — the exact opposite of the \"Oldest first\" comment and of the documented `CAIRN_CACHE_MAX_BYTES` behaviour; the hot working set is evicted while the stalest blobs survive.\n\n🔴 `bug` services/proxy/src/sweep.rs:230: `clear_partials` unlinks every file in `incoming/` with no age check, but `BlobStore::temp_path` (store.rs:201) puts *live* in-flight downloads there; each sweep unlinks the temp files of concurrent fetches, whose `commit` rename (store.rs:259) then fails, so every sweep fails all downloads in flight at that moment.\n\n🟠 `bug` services/proxy/src/metrics.rs:94: `values()` loads `sweep_bytes_reclaimed` at index 4 and `sweep_blobs_removed` at index 5, but `COUNTERS` puts `..._blobs_removed_total` at index 4 and `..._bytes_reclaimed_total` at index 5, so the two new counters are rendered under each other's names — the exact mix-up the comment above `COUNTERS` warns about, and the ops doc tells operators to alert on the misrendered `cairn_proxy_sweep_bytes_reclaimed_total`.\n\n🟠 `bug` services/proxy/src/routes/admin.rs:76: the admin route calls `app.sweeper.sweep(dry_run)` directly, bypassing the `running` mutex that only `Sweeper::run` takes (sweep.rs:83), so an admin-triggered sweep can run concurrently with the background sweep (or with another admin sweep) — the exact double-sweep over-eviction the module doc at sweep.rs:10-12 says the mutex exists to prevent.\n\n🟠 `bug` services/proxy/src/sweep.rs:119: an unreferenced blob is removed with no `min_age` grace, but a blob is legitimately unreferenced in the window between `writer.commit()` (cache.rs:151) and `store.link` (cache.rs:163), which spans a registry round-trip; a sweep in that window deletes the freshly committed blob and the request 500s at cache.rs:90 (\"a blob committed by this request is already missing\").\n\n🟠 `performance` services/proxy/src/sweep.rs:84: `run()` (and the admin handler via admin.rs:76) executes the fully synchronous walk-and-unlink `sweep()` directly on a tokio worker thread instead of `spawn_blocking`; the router comment in routes/mod.rs concedes a sweep \"legitimately takes longer than ten seconds\", so a large store blocks an async runtime worker for that whole time.\n\n🟡 `bug` services/proxy/src/main.rs:108: `tokio::time::interval` completes its first tick immediately, so the first sweep runs at startup — the doc comment at lines 101-102 claims the first tick is one interval away precisely to avoid this; `interval_at(Instant::now() + period, period)` is what the comment describes.\n\n🟡 `bug` services/proxy/src/sweep.rs:164: `fs::metadata` follows symlinks, so a link is counted at the size of its *target* (and a symlinked directory is recursed into and its contents unlinked), the inverse of the comment's claim that \"a link is counted at the size of the link\"; `symlink_metadata` is what the comment describes.\n\n🔵 `bug` services/proxy/src/sweep.rs:134: when `fs::remove_file` fails on line 126, the blob is still counted in `removed`/`bytes`/`remaining` and pushed to `gone`, so the reported reclaim overstates reality and `forget` deletes the index entries of a blob that is still on disk, orphaning it until a later sweep.","auth":{"mode":"api_key"},"effort":"high","elapsed_secs":168.31,"error":null,"error_kind":null,"instructions":[],"model":"anthropic/claude-fable-5","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-1fnaCz/.git","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-1fnaCz/.afi","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-1fnaCz/.agents","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-1fnaCz/.codex","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-1fnaCz/AGENTS.md","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-1fnaCz/CLAUDE.md"],"readable_paths":["/"],"readable_roots":["/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-1fnaCz","/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-ZUUZqE"]},"schema_version":1,"source":"openrouter","sources":[{"auth":{"mode":"api_key"},"source":"openrouter","usage":{"cache_read_tokens":0,"cache_write_tokens":0,"cost_usd":1.70665,"estimated_tokens":0,"input_tokens":106515,"output_tokens":2121,"reasoning_tokens":10709,"requests":3,"total_tokens":119345}}],"system_prompt":{"file":null,"mode":"builtin"},"tools":["read_file","write_file","edit_file","list_dir","search_files","glob_files","run_bash","wait_background"],"usage":{"budget":{"converged":false,"hard_ratio":0.95,"limit_usd":20.0,"soft_ratio":0.8,"spent_usd":1.70665,"stopped":false},"cache_read_tokens":0,"cache_write_tokens":0,"cost_usd":1.70665,"estimated_tokens":0,"input_tokens":106515,"output_tokens":2121,"reasoning_tokens":10709,"refused_by_approval":0,"refused_by_policy":0,"refused_tool_calls":0,"requests":3,"total_tokens":119345}}