diff --git a/Cargo.toml b/Cargo.toml
index 46bbd85..ad8e272 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -233,13 +233,25 @@ ort-tract = "0.4"
 ndarray = "0.17"
 
 [profile.dev]
-# Dependencies optimised even in dev builds — wgpu and image decoding are
-# unusably slow otherwise, and they rarely need debugging.
+# Dev builds are tuned for how fast they *compile*, not for how fast they run.
+# Optimisation is a release concern; `[profile.release]` below is where it
+# belongs.
+#
+# This deliberately reverses an earlier choice. Dependencies used to be built
+# at `opt-level = 2` here, because wgpu and image decoding are slow without it.
+# That is still true, and it is the price: a debug run of the app, and the
+# decode- and GPU-heavy tests, are slower than they were. What it buys is that
+# nothing has to be optimised before it can be compiled — which is the cost
+# paid on every edit, by every worktree, rather than only when something is
+# actually run.
+#
+# If a particular crate turns out to be the one that makes a test unbearable,
+# raise it alone rather than restoring the blanket rule:
+#
+#   [profile.dev.package.zune-jpeg]
+#   opt-level = 2
 opt-level = 0
 
-[profile.dev.package."*"]
-opt-level = 2
-
 [profile.release]
 lto = "thin"
 codegen-units = 1