diff --git a/Cargo.toml b/Cargo.toml
index 7797232..b606106 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -36,3 +36,12 @@ serde = { version = "1", features = ["derive"] }
 # parsed back. Exercised (with a 1-ULP canary value) by aura-cli's
 # `f64_blueprint_param_survives_store_round_trip_bit_identically`.
 serde_json = { version = "1", features = ["float_roundtrip"] }
+
+# Dependencies at opt-level 2, workspace crates at the dev default (0): the E2E
+# suite spawns the debug `aura` binary whose wall-clock is dominated by dependency
+# code (zip inflate, sha2 dylib hashing, serde) — optimizing deps is multiplicative
+# there, while workspace crates stay fast-to-rebuild and debuggable. Float pins are
+# unaffected: every pinned float is computed by workspace code (IEEE semantics are
+# opt-level-independent in Rust regardless).
+[profile.dev.package."*"]
+opt-level = 2