diff --git a/CLAUDE.md b/CLAUDE.md
index 0052207..ffe1b77 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -202,6 +202,12 @@ session was stopped. So:
   until the change is done; the whole workspace's once, at the end.
 * Builds and test binaries live under `target/`, a link to `/mnt/fast`; linking through
   `/mnt/user` (FUSE) once took the load to 248 on its own.
+* **Memory is the tighter limit.** Tower has 31 GB, no swap, and the containers leave about 4-7
+  GB. A build past that stalls everything on page faults: load 160 with the CPU idle and the
+  disks quiet, many processes blocked (`node_procs_blocked`, `node_vmstat_pgmajfault`). On
+  2026-10-18 linking a 431 MB test binary did it for 54 minutes. So `[profile.dev]` keeps only
+  line tables and dependencies no debug info; keep it that way, and look at `MemAvailable` beside
+  the load.
 
 The Rust is formatted by rustfmt (`rustfmt.toml`) and kept free of clippy's warnings. A clone
 turns on the hook once: `git config core.hooksPath .githooks`; and `git config blame.ignoreRevsFile
diff --git a/Cargo.toml b/Cargo.toml
index 83d7843..6dac8e4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -42,3 +42,12 @@ tracing = "0.1.44"
 tracing-opentelemetry = { version = "0.34", default-features = false }
 tracing-subscriber = { version = "0.3.23", features = ["env-filter", "json"] }
 url = "2.5.8"
+
+# Backtraces keep file and line; the full debug info made a 431 MB test binary whose link ran
+# Tower, which has no swap, out of memory and stalled it for most of an hour (2026-10-18).
+[profile.dev]
+debug = "line-tables-only"
+
+# Nobody steps through dependencies.
+[profile.dev.package."*"]
+debug = false