diff --git a/CLAUDE.md b/CLAUDE.md
index b13ca83..c5371a8 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -570,3 +570,16 @@ Layer 2: 36 genesis jets (hash, poly_eval, merkle_verify, fri_fold, ntt families
- `Cargo.toml` dependency versions โ discuss before changing
- `specs/` โ canonical spec, change there first then propagate
+
+
+## no_std dependency gate
+
+Every commit runs this gate from the repository root with committed sibling
+checkouts and the `thumbv7em-none-eabi` target installed:
+
+```sh
+cargo build -p cyber-nox --no-default-features --target thumbv7em-none-eabi --locked
+```
+
+A missing target or dependency is a red prerequisite, not a passed gate. This
+checks real library code generation without std; host tests do not replace it.
diff --git a/rs/Cargo.toml b/rs/Cargo.toml
index 341cb82..443daf7 100644
--- a/rs/Cargo.toml
+++ b/rs/Cargo.toml
@@ -14,7 +14,7 @@ path = "lib.rs"
[features]
default = []
-std = []
+std = ["hemera/std"]
# threaded par_binary executor โ opt-in. T1 (sequential-equivalence)
# makes the sequential path canonical; forking the arena per binary
# pattern is expensive, so std alone must not switch execution mode
@@ -26,7 +26,7 @@ honeycrisp = ["std", "dep:acpu"]
[dependencies]
nebu = { package = "strata-nebu", version = "0.1", path = "../../strata/nebu/rs" }
-hemera = { package = "cyber-hemera", version = "0.3", path = "../../hemera/rs" }
+hemera = { package = "cyber-hemera", version = "0.3", path = "../../hemera/rs", default-features = false }
cyber-lens-core = { version = "0.1", path = "../../lens/core", optional = true }
cyber-lens-brakedown = { version = "0.1", path = "../../lens/brakedown", optional = true }
acpu = { version = "0.2", optional = true }