{"answer":"Everything needed is in hand. Findings:\n\n🔴 `bug` services/proxy/src/sweep.rs:140: `forget(&index, &gone)` is not gated on `dry_run` and `gone` is filled even in a dry run (lines 136-137 run unconditionally), so `POST /v1/admin/cache/sweep?dry_run=true` really unlinks the index entries of every blob it merely reported — the blobs it \"did not remove\" become unreachable cache misses immediately and are deleted as unreferenced on the very next real sweep, the opposite of the documented \"reports … without removing anything\".\n\n🔴 `bug` services/proxy/src/sweep.rs:102: `sort_by_key(|c| c.age)` orders candidates **youngest first** (smallest `now - mtime` first), yet the eviction loop removes from the front, so an over-ceiling sweep deletes the most recently fetched blobs and keeps the oldest — an inverted LRU that thrashes exactly the packages current builds are using; the sort needs to be descending by age.\n\n🟠 `bug` services/proxy/src/sweep.rs:119: a blob with no index entry is removed with no `min_age` grace, but on the miss path a blob exists unlinked for the whole window between `writer.commit()` (services/proxy/src/routes/cache.rs:151) and `store.link()` (cache.rs:163), which includes a network round-trip to the registry — a sweep in that window deletes the just-committed blob and the request 500s at cache.rs:90; reading the index snapshot (line 92) *before* walking blobs (line 95) widens the race further.\n\n🟠 `bug` services/proxy/src/sweep.rs:230: `clear_partials` unlinks every file in `incoming` with no age or liveness check, but `incoming` is where `BlobWriter` (store.rs:171-180) is actively writing in-flight downloads — a sweep during a fetch unlinks the live temp file, and `commit`'s `fs::rename` (store.rs:259) then fails with NotFound, failing the request; the doc's claim that \"a file in `incoming` is a fetch that is not coming back\" is false while any fetch is in flight.\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` (lines 50-57) names index 4 `cairn_proxy_sweep_blobs_removed_total` and index 5 `..._bytes_reclaimed_total` — each sweep counter is exported under the other's name, which is precisely the mix-up the comment on `COUNTERS` warns about, and docs/operations.md tells operators to alert on the bytes counter that will actually carry the blob count.\n\n🟠 `bug` services/proxy/src/routes/admin.rs:76: the admin route calls `app.sweeper.sweep(dry_run)` directly instead of `run()`, skipping the `running` mutex (sweep.rs:83), so an on-demand sweep runs concurrently with the background sweep (or another admin sweep) — the exact two-sweeps-over-one-total situation the module doc (sweep.rs:10-12) says must never happen, each deleting from a total the other is changing.\n\n🟡 `performance` services/proxy/src/routes/admin.rs:76: `sweeper.sweep()` is a fully synchronous filesystem walk (readdir + stat over up to 65k directories, plus reading every index file) executed inline on a tokio worker thread — routes/mod.rs:125 itself says a sweep \"legitimately takes longer than ten seconds\" — blocking that runtime thread for the duration; the same applies to `app.sweeper.run().await` in the spawned task at services/proxy/src/main.rs:116; both should go through `spawn_blocking`.","auth":{"mode":"api_key"},"effort":"high","elapsed_secs":220.086,"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-PVUjaV/.git","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-PVUjaV/.afi","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-PVUjaV/.agents","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-PVUjaV/.codex","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-PVUjaV/AGENTS.md","/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-PVUjaV/CLAUDE.md"],"readable_paths":["/"],"readable_roots":["/private/var/folders/d1/tvmyp5cs1gz38rltf390ddpw0000gn/T/benchee-agent-PVUjaV","/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-EmV2uK"]},"schema_version":1,"source":"openrouter","sources":[{"auth":{"mode":"api_key"},"source":"openrouter","usage":{"cache_read_tokens":0,"cache_write_tokens":0,"cost_usd":2.26771,"estimated_tokens":0,"input_tokens":145251,"output_tokens":2083,"reasoning_tokens":14221,"requests":4,"total_tokens":161555}}],"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":2.26771,"stopped":false},"cache_read_tokens":0,"cache_write_tokens":0,"cost_usd":2.26771,"estimated_tokens":0,"input_tokens":145251,"output_tokens":2083,"reasoning_tokens":14221,"refused_by_approval":0,"refused_by_policy":0,"refused_tool_calls":0,"requests":4,"total_tokens":161555}}