diff --git a/Makefile b/Makefile
index 013b157..e0de9e0 100644
--- a/Makefile
+++ b/Makefile
@@ -24,8 +24,8 @@ docker-build: ## 🐳 Build the Docker image
 		-t ghcr.io/lambdaclass/ethlambda:$(DOCKER_TAG) .
 	@echo
 
-# 2026-04-28: bump for leanSpec PR #682 (validate_attestation future-slot bound).
-LEAN_SPEC_COMMIT_HASH:=62eff6e7e6041a283877a546a07cb3b83f4f7d5b
+# 2026-04-29
+LEAN_SPEC_COMMIT_HASH:=495c29d49f2b12b7cc240c4028e15d4253a7d54e
 
 leanSpec:
 	git clone https://github.com/leanEthereum/leanSpec.git --single-branch
diff --git a/crates/blockchain/tests/forkchoice_spectests.rs b/crates/blockchain/tests/forkchoice_spectests.rs
index 13d8cf7..23f4503 100644
--- a/crates/blockchain/tests/forkchoice_spectests.rs
+++ b/crates/blockchain/tests/forkchoice_spectests.rs
@@ -21,7 +21,7 @@ const SUPPORTED_FIXTURE_FORMAT: &str = "fork_choice_test";
 mod common;
 mod types;
 
-/// List of skipped tests
+/// List of skipped tests.
 const SKIP_TESTS: &[&str] = &[];
 
 fn run(path: &Path) -> datatest_stable::Result<()> {
@@ -221,9 +221,12 @@ fn validate_checks(
             .as_ref()
             .and_then(|label| block_registry.get(label).copied())
     });
-    if checks.safe_target.is_some() {
-        return Err(format!("Step {}: 'safeTarget' check not supported", step_idx).into());
-    }
+    let resolved_safe_target_root = checks.safe_target.or_else(|| {
+        checks
+            .safe_target_root_label
+            .as_ref()
+            .and_then(|label| block_registry.get(label).copied())
+    });
     // Validate attestationTargetSlot
     if let Some(expected_slot) = checks.attestation_target_slot {
         let target = store::get_attestation_target(st);
@@ -330,6 +333,30 @@ fn validate_checks(
         }
     }
 
+    // Validate safeTargetSlot
+    if let Some(expected_slot) = checks.safe_target_slot {
+        let actual_slot = st.safe_target_slot();
+        if actual_slot != expected_slot {
+            return Err(format!(
+                "Step {}: safeTargetSlot mismatch: expected {}, got {}",
+                step_idx, expected_slot, actual_slot
+            )
+            .into());
+        }
+    }
+
+    // Validate safeTarget root (resolved from label if root not provided)
+    if let Some(ref expected_root) = resolved_safe_target_root {
+        let actual_root = st.safe_target();
+        if actual_root != *expected_root {
+            return Err(format!(
+                "Step {}: safeTarget mismatch: expected {:?}, got {:?}",
+                step_idx, expected_root, actual_root
+            )
+            .into());
+        }
+    }
+
     // Validate attestationChecks
     if let Some(ref att_checks) = checks.attestation_checks {
         for att_check in att_checks {
diff --git a/crates/blockchain/tests/types.rs b/crates/blockchain/tests/types.rs
index a1f0232..97b56dd 100644
--- a/crates/blockchain/tests/types.rs
+++ b/crates/blockchain/tests/types.rs
@@ -136,38 +136,51 @@ impl BlockStepData {
 // Check Types
 // ============================================================================
 
+/// Store-state expectations for a fork choice test step.
+///
+/// All fields are optional; only fields explicitly set by the fixture are validated.
+/// Root-typed fields have a `*RootLabel` companion that resolves a block label via the
+/// step's block registry, mirroring the leanSpec fixture schema.
 #[derive(Debug, Clone, Deserialize)]
 pub struct StoreChecks {
-    // Validated fields
+    /// Expected store time in intervals since genesis.
+    pub time: Option<u64>,
+
     #[serde(rename = "headSlot")]
     pub head_slot: Option<u64>,
     #[serde(rename = "headRoot")]
     pub head_root: Option<H256>,
-    #[serde(rename = "attestationChecks")]
-    pub attestation_checks: Option<Vec<AttestationCheck>>,
-    #[serde(rename = "attestationTargetSlot")]
-    pub attestation_target_slot: Option<u64>,
-
-    /// Expected store time in intervals since genesis (validated when present).
-    pub time: Option<u64>,
-
-    // Unsupported fields (will error if present in test fixture)
     #[serde(rename = "headRootLabel")]
     pub head_root_label: Option<String>,
+
     #[serde(rename = "latestJustifiedSlot")]
     pub latest_justified_slot: Option<u64>,
     #[serde(rename = "latestJustifiedRoot")]
     pub latest_justified_root: Option<H256>,
     #[serde(rename = "latestJustifiedRootLabel")]
     pub latest_justified_root_label: Option<String>,
+
     #[serde(rename = "latestFinalizedSlot")]
     pub latest_finalized_slot: Option<u64>,
     #[serde(rename = "latestFinalizedRoot")]
     pub latest_finalized_root: Option<H256>,
     #[serde(rename = "latestFinalizedRootLabel")]
     pub latest_finalized_root_label: Option<String>,
+
+    /// Legacy single-field schema; expected safe target block root.
     #[serde(rename = "safeTarget")]
     pub safe_target: Option<H256>,
+    /// Expected slot of the safe target block (leanSpec #680 schema).
+    #[serde(rename = "safeTargetSlot")]
+    pub safe_target_slot: Option<u64>,
+    /// Expected safe target block root by label reference (leanSpec #680 schema).
+    #[serde(rename = "safeTargetRootLabel")]
+    pub safe_target_root_label: Option<String>,
+
+    #[serde(rename = "attestationTargetSlot")]
+    pub attestation_target_slot: Option<u64>,
+    #[serde(rename = "attestationChecks")]
+    pub attestation_checks: Option<Vec<AttestationCheck>>,
     #[serde(rename = "lexicographicHeadAmong")]
     pub lexicographic_head_among: Option<Vec<String>>,
 }