grandinetech · ArtiomTr · May 7, 2026 · Apr 28, 2026 · May 6, 2026
diff --git a/lean_client/Makefile b/lean_client/Makefile
@@ -1,8 +1,8 @@
 ### Variables
 
 # Commit of lean specification. Allows to specify which spec version to use,
-#   when generating test vectors. Currently set to devnet-3 spec version.
-LEAN_SPEC_COMMIT ?= f64b1038caef043849147c791ddd64907fbf19a7
+#   when generating test vectors. Pinned to leanSpec PR #682 merge commit.
+LEAN_SPEC_COMMIT ?= 62eff6e7e6041a283877a546a07cb3b83f4f7d5b
 # Docker image name. Used for both release (with publish) and local builds.
 DOCKER_REPO ?= sifrai/lean
 # Image tag.

diff --git a/lean_client/fork_choice/src/handlers.rs b/lean_client/fork_choice/src/handlers.rs
@@ -8,7 +8,8 @@ use tracing::warn;
 
 use crate::block_cache::BlockCache;
 use crate::store::{
-    INTERVALS_PER_SLOT, MILLIS_PER_INTERVAL, STATE_PRUNE_BUFFER, Store, tick_interval, update_head,
+    GOSSIP_DISPARITY_INTERVALS, INTERVALS_PER_SLOT, MILLIS_PER_INTERVAL, STATE_PRUNE_BUFFER, Store,
+    tick_interval, update_head,
 };
 
 #[inline]
@@ -74,15 +75,19 @@ fn validate_attestation_data(store: &Store, data: &AttestationData) -> Result<()
         head_block.slot.0
     );
 
-    // Validate attestation is not too far in the future
-    // We allow a small margin for clock disparity (1 slot), but no further.
-    let current_slot = store.time / INTERVALS_PER_SLOT;
+    // Honest validators emit votes only after their slot has begun. Allow exactly
+    // one interval (~800 ms) of clock skew between peers; a whole-slot margin would
+    // let an adversary pre-publish next-slot aggregates ahead of any honest
+    // validator. Lean analogue of mainnet's MAXIMUM_GOSSIP_CLOCK_DISPARITY.
+    let attestation_start_interval = data.slot.0 * INTERVALS_PER_SLOT;
 
     ensure!(
-        data.slot.0 <= current_slot + 1,
-        "Attestation too far in future: attestation slot {} > current slot {} + 1",
+        attestation_start_interval <= store.time + GOSSIP_DISPARITY_INTERVALS,
+        "Attestation too far in future: data slot {} (start interval {}) > store time {} + {}",
         data.slot.0,
-        current_slot
+        attestation_start_interval,
+        store.time,
+        GOSSIP_DISPARITY_INTERVALS,
     );
 
     Ok(())

diff --git a/lean_client/fork_choice/src/store.rs b/lean_client/fork_choice/src/store.rs
@@ -16,6 +16,11 @@ pub const SECONDS_PER_SLOT: u64 = 4;
 /// Milliseconds per interval: (4 * 1000) / 5 = 800ms
 /// Using milliseconds avoids integer division truncation (4/5 = 0 in integer math)
 pub const MILLIS_PER_INTERVAL: u64 = (SECONDS_PER_SLOT * 1000) / INTERVALS_PER_SLOT;
+/// Future-slot tolerance for attestation gossip, in intervals.
+/// Bounds the clock skew the time check absorbs when admitting a vote whose
+/// slot has not yet started locally. One interval is ~800 ms — the lean
+/// analogue of mainnet's MAXIMUM_GOSSIP_CLOCK_DISPARITY.
+pub const GOSSIP_DISPARITY_INTERVALS: u64 = 1;
 
 /// Forkchoice store tracking chain state and validator attestations
 

diff --git a/...t_vectors/api_endpoint/devnet/api/test_api_endpoints/test_aggregator_status_disabled.json b/...t_vectors/api_endpoint/devnet/api/test_api_endpoints/test_aggregator_status_disabled.json
@@ -4,21 +4,22 @@
         "leanEnv": "prod",
         "endpoint": "/lean/v0/admin/aggregator",
         "method": "GET",
-        "initialIsAggregator": false,
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "is_aggregator": false
         },
         "_info": {
+            "hash": "0xb999abf70a1e969388d7fe0e3a958ffb37a25ef5447e7dd7a2c72fd0b956e604",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_aggregator_status_disabled[fork_Devnet]",
             "description": "GET aggregator status on a node started with aggregator disabled.",
             "fixtureFormat": "api_endpoint"
         }
     }
-}
+}
diff --git a/...st_vectors/api_endpoint/devnet/api/test_api_endpoints/test_aggregator_status_enabled.json b/...st_vectors/api_endpoint/devnet/api/test_api_endpoints/test_aggregator_status_enabled.json
@@ -4,21 +4,22 @@
         "leanEnv": "prod",
         "endpoint": "/lean/v0/admin/aggregator",
         "method": "GET",
-        "initialIsAggregator": true,
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "initialIsAggregator": true,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "is_aggregator": true
         },
         "_info": {
+            "hash": "0x8999239b61dc6dd3bea6d273a03110f4dc524517448ae3cbeeaa7633b2ccbbeb",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_aggregator_status_enabled[fork_Devnet]",
             "description": "GET aggregator status on a node started with aggregator enabled.",
             "fixtureFormat": "api_endpoint"
         }
     }
-}
+}
diff --git a/...t_vectors/api_endpoint/devnet/api/test_api_endpoints/test_aggregator_toggle_activate.json b/...t_vectors/api_endpoint/devnet/api/test_api_endpoints/test_aggregator_toggle_activate.json
@@ -4,25 +4,26 @@
         "leanEnv": "prod",
         "endpoint": "/lean/v0/admin/aggregator",
         "method": "POST",
-        "initialIsAggregator": false,
-        "requestBody": {
-            "enabled": true
-        },
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "requestBody": {
+            "enabled": true
+        },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "is_aggregator": true,
             "previous": false
         },
         "_info": {
+            "hash": "0xd8bcd3cbe421e33455bca1a2156267b360311465240df93fbac98b8001e00a03",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_aggregator_toggle_activate[fork_Devnet]",
             "description": "POST enable=true flips the role from off to on.",
             "fixtureFormat": "api_endpoint"
         }
     }
-}
+}
diff --git a/...vectors/api_endpoint/devnet/api/test_api_endpoints/test_aggregator_toggle_deactivate.json b/...vectors/api_endpoint/devnet/api/test_api_endpoints/test_aggregator_toggle_deactivate.json
@@ -4,25 +4,26 @@
         "leanEnv": "prod",
         "endpoint": "/lean/v0/admin/aggregator",
         "method": "POST",
-        "initialIsAggregator": true,
-        "requestBody": {
-            "enabled": false
-        },
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "requestBody": {
+            "enabled": false
+        },
+        "initialIsAggregator": true,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "is_aggregator": false,
             "previous": true
         },
         "_info": {
+            "hash": "0x3222c740014574a5fc103db4a43a6812ab7801bf1de8a03f87d7ed699a0ac337",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_aggregator_toggle_deactivate[fork_Devnet]",
             "description": "POST enable=false flips the role from on to off.",
             "fixtureFormat": "api_endpoint"
         }
     }
-}
+}
diff --git a/...api_endpoint/devnet/api/test_api_endpoints/test_aggregator_toggle_idempotent_disable.json b/...api_endpoint/devnet/api/test_api_endpoints/test_aggregator_toggle_idempotent_disable.json
@@ -4,25 +4,26 @@
         "leanEnv": "prod",
         "endpoint": "/lean/v0/admin/aggregator",
         "method": "POST",
-        "initialIsAggregator": false,
-        "requestBody": {
-            "enabled": false
-        },
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "requestBody": {
+            "enabled": false
+        },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "is_aggregator": false,
             "previous": false
         },
         "_info": {
+            "hash": "0xeab1eb434423c8224bdd3b35ae2300ed900ce420e14e1af7eb3f960f9a261916",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_aggregator_toggle_idempotent_disable[fork_Devnet]",
             "description": "POST enable=false on an already-disabled node returns previous=false and is a no-op.",
             "fixtureFormat": "api_endpoint"
         }
     }
-}
+}
diff --git a/.../api_endpoint/devnet/api/test_api_endpoints/test_aggregator_toggle_idempotent_enable.json b/.../api_endpoint/devnet/api/test_api_endpoints/test_aggregator_toggle_idempotent_enable.json
@@ -4,25 +4,26 @@
         "leanEnv": "prod",
         "endpoint": "/lean/v0/admin/aggregator",
         "method": "POST",
-        "initialIsAggregator": true,
-        "requestBody": {
-            "enabled": true
-        },
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "requestBody": {
+            "enabled": true
+        },
+        "initialIsAggregator": true,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "is_aggregator": true,
             "previous": true
         },
         "_info": {
+            "hash": "0xe4d9c5d8178a36c7ddade1372c479b286f96080d2fe553ced3ff1d37f81b29b5",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_aggregator_toggle_idempotent_enable[fork_Devnet]",
             "description": "POST enable=true on an already-enabled node returns previous=true and is a no-op.",
             "fixtureFormat": "api_endpoint"
         }
     }
-}
+}
diff --git a/...ient/test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_finalized_state_4v.json b/...ient/test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_finalized_state_4v.json
@@ -3,15 +3,17 @@
         "network": "Devnet",
         "leanEnv": "prod",
         "endpoint": "/lean/v0/states/finalized",
+        "method": "GET",
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/octet-stream",
         "expectedBody": "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",
         "_info": {
-            "hash": "0x0bad805dc81534775712ed53d44f92930678bd44be08143183e173274ec5cdd8",
+            "hash": "0xafebe406f0f70121fae02afeb9082de3012203b847efbb50376e855f801f4cfd",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_finalized_state_4v[fork_Devnet]",
             "description": "Full SSZ-encoded finalized state for a 4-validator genesis.",

diff --git a/lean_client/test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_fork_choice_4v.json b/lean_client/test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_fork_choice_4v.json
@@ -3,10 +3,12 @@
         "network": "Devnet",
         "leanEnv": "prod",
         "endpoint": "/lean/v0/fork_choice",
+        "method": "GET",
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
@@ -32,7 +34,7 @@
             "validator_count": 4
         },
         "_info": {
-            "hash": "0x9fef671ba5f90989e6a16abe45cbe760772d2e64ead892dac806f910bd841dc5",
+            "hash": "0x3ca9c1339d2685d53ba440deac842390b3c3bd33467420f7e8afe1f969a20bb8",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_fork_choice_4v[fork_Devnet]",
             "description": "Fork choice tree at genesis: single node, zero attestation weights.",

diff --git a/lean_client/test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_fork_choice_8v.json b/lean_client/test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_fork_choice_8v.json
@@ -3,10 +3,12 @@
         "network": "Devnet",
         "leanEnv": "prod",
         "endpoint": "/lean/v0/fork_choice",
+        "method": "GET",
         "genesisParams": {
             "numValidators": 8,
             "genesisTime": 0
         },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
@@ -32,7 +34,7 @@
             "validator_count": 8
         },
         "_info": {
-            "hash": "0x0b66df5b4fb0c872fa9f0f3f69f241c7214349e3d28d708da46a264eaf12c63a",
+            "hash": "0xe3cd4c738e97a2078e332c512fddb24bf56c0420e139f2c58064f5287b45e2d6",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_fork_choice_8v[fork_Devnet]",
             "description": "Fork choice tree at genesis with 8 validators. Same shape, higher count.",

diff --git a/lean_client/test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_health.json b/lean_client/test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_health.json
@@ -3,18 +3,20 @@
         "network": "Devnet",
         "leanEnv": "prod",
         "endpoint": "/lean/v0/health",
+        "method": "GET",
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "status": "healthy",
             "service": "lean-rpc-api"
         },
         "_info": {
-            "hash": "0xde9ad15a93299a23397a0fd4c8300527f00d699e4661fb4ec0b4012f823f7c72",
+            "hash": "0xe4a0ee746c2b746fd53a5fb07b37b51fa44acd9dd8b75455a7780568404879ae",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_health[fork_Devnet]",
             "description": "Health returns a fixed payload independent of consensus state.",

diff --git a/...test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_justified_checkpoint_4v.json b/...test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_justified_checkpoint_4v.json
@@ -3,18 +3,20 @@
         "network": "Devnet",
         "leanEnv": "prod",
         "endpoint": "/lean/v0/checkpoints/justified",
+        "method": "GET",
         "genesisParams": {
             "numValidators": 4,
             "genesisTime": 0
         },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "slot": 0,
             "root": "0xd123d3d19ba32a08df9b3bf9e55e4447d1a3a3b4f905583d013b8f05c77d585e"
         },
         "_info": {
-            "hash": "0xf8fb33f5448cfe776905f89f79078bd7c095f353fe37c889346220c9bd46b176",
+            "hash": "0xad4d6042d90973af1c9dd20a7c02f77b5c49fcebf1ed17ae80e7546bb81588ec",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_justified_checkpoint_4v[fork_Devnet]",
             "description": "Justified checkpoint at genesis with 4 validators.",

diff --git a/...test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_justified_checkpoint_8v.json b/...test_vectors/api_endpoint/devnet/api/test_api_endpoints/test_justified_checkpoint_8v.json
@@ -3,18 +3,20 @@
         "network": "Devnet",
         "leanEnv": "prod",
         "endpoint": "/lean/v0/checkpoints/justified",
+        "method": "GET",
         "genesisParams": {
             "numValidators": 8,
             "genesisTime": 0
         },
+        "initialIsAggregator": false,
         "expectedStatusCode": 200,
         "expectedContentType": "application/json",
         "expectedBody": {
             "slot": 0,
             "root": "0xd567e95979f6ce2186cbada494967c77142153c6e5ab38f2bd7a23ee6b92170b"
         },
         "_info": {
-            "hash": "0x07ba861cfad6285a8da6bac8b7d5ef3ef08d67b52222f75a4383c65a241fb513",
+            "hash": "0xa4adc9beef1276e99aee48c2eb46ecba782ddac00a8473655a89a81af5b9ede4",
             "comment": "`leanSpec` generated test",
             "testId": "tests/consensus/devnet/api/test_api_endpoints.py::test_justified_checkpoint_8v[fork_Devnet]",
             "description": "Justified checkpoint at genesis with 8 validators. Root differs from 4v.",

diff --git a/...vectors/api_endpoint/devnet/api/test_api_post_genesis/test_finalized_state_at_slot_3.json b/...vectors/api_endpoint/devnet/api/test_api_post_genesis/test_finalized_state_at_slot_3.json
@@ -0,0 +1,24 @@
+{
+    "tests/consensus/devnet/api/test_api_post_genesis.py::test_finalized_state_at_slot_3[fork_Devnet][fork_devnet-api_endpoint]": {
+        "network": "Devnet",
+        "leanEnv": "prod",
+        "endpoint": "/lean/v0/states/finalized",
+        "method": "GET",
+        "genesisParams": {
+            "numValidators": 4,
+            "genesisTime": 0,
+            "anchorSlot": 3
+        },
+        "initialIsAggregator": false,
+        "expectedStatusCode": 200,
+        "expectedContentType": "application/octet-stream",
+        "expectedBody": "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",
+        "_info": {
+            "hash": "0x213780c9845f99dd9417c4462a66baeda8bc46d2e53d7c6d3035ef00b05bf0b4",
+            "comment": "`leanSpec` generated test",
+            "testId": "tests/consensus/devnet/api/test_api_post_genesis.py::test_finalized_state_at_slot_3[fork_Devnet]",
+            "description": "Finalized-state response returns the SSZ-encoded anchor state after chain advance.\n\n    Finalization has not yet moved past genesis (no attestations have\n    been injected), but the served state now carries non-empty\n    historical_block_hashes because the chain has processed three empty\n    blocks. Pins the exact SSZ bytes at that configuration.",
+            "fixtureFormat": "api_endpoint"
+        }
+    }
+}