diff --git a/onchain/src/Optimizer.sol b/onchain/src/Optimizer.sol
index e849323..f564a9f 100644
--- a/onchain/src/Optimizer.sol
+++ b/onchain/src/Optimizer.sol
@@ -75,6 +75,19 @@ contract Optimizer is Initializable, UUPSUpgradeable {
     /// @dev Reverts if the caller is not the admin.
     error UnauthorizedAccount(address account);
 
+    /// @dev Gas budget forwarded to calculateParams via staticcall.
+    ///      Evolved programs that exceed this are treated as crashes — same outcome
+    ///      as a revert — and getLiquidityParams() returns bear defaults instead.
+    ///      200 000 gives ~13x headroom over the current seed (~15 k gas) while
+    ///      preventing unbounded growth from blocking recenter().
+    ///
+    ///      Note (EIP-150 / 63-64 rule): the outer getLiquidityParams() call must
+    ///      arrive with at least ⌈200_000 × 64/63⌉ ≈ 203_175 gas for the inner
+    ///      staticcall to actually receive 200 000.  Callers with exactly 200–203 k
+    ///      gas will see a spurious bear-defaults fallback.  This is not a practical
+    ///      concern from recenter(), which always has abundant gas.
+    uint256 internal constant CALCULATE_PARAMS_GAS_LIMIT = 200_000;
+
     /**
      * @notice Initialize the Optimizer.
      * @param _kraiken The address of the Kraiken token.
@@ -131,13 +144,6 @@ contract Optimizer is Initializable, UUPSUpgradeable {
         lastRecenterTimestamp = block.timestamp;
     }
 
-    /// @dev Gas budget forwarded to calculateParams via staticcall.
-    ///      Evolved programs that exceed this are treated as crashes — same outcome
-    ///      as a revert — and getLiquidityParams() returns bear defaults instead.
-    ///      200 000 gives ~13x headroom over the current seed (~15 k gas) while
-    ///      keeping unbounded growth from ever blocking recenter().
-    uint256 internal constant CALCULATE_PARAMS_GAS_LIMIT = 200_000;
-
     // ---- Dyadic rational helpers ----
 
     /**
@@ -150,7 +156,10 @@ contract Optimizer is Initializable, UUPSUpgradeable {
 
     /**
      * @notice Safe bear-mode defaults returned when calculateParams exceeds its
-     *         gas budget or reverts. Mirrors the catch block in LiquidityManager.
+     *         gas budget or reverts.
+     * @dev Values must stay in sync with the catch block in LiquidityManager.recenter()
+     *      ({capitalInefficiency:0, anchorShare:3e17, anchorWidth:100, discoveryDepth:3e17}).
+     *      Update both locations together if the safe defaults ever change.
      */
     function _bearDefaults()
         internal
@@ -347,6 +356,11 @@ contract Optimizer is Initializable, UUPSUpgradeable {
             abi.encodeCall(this.calculateParams, (inputs))
         );
         if (!ok) return _bearDefaults();
+        // ABI encoding of (uint256, uint256, uint24, uint256) is exactly 128 bytes
+        // (each value padded to 32 bytes).  A truncated return — e.g. from a
+        // malformed evolved program — would cause abi.decode to revert; guard here
+        // so all failure modes fall back via _bearDefaults().
+        if (ret.length < 128) return _bearDefaults();
         return abi.decode(ret, (uint256, uint256, uint24, uint256));
     }
 }
diff --git a/onchain/test/FitnessEvaluator.t.sol b/onchain/test/FitnessEvaluator.t.sol
index e726872..20cdf40 100644
--- a/onchain/test/FitnessEvaluator.t.sol
+++ b/onchain/test/FitnessEvaluator.t.sol
@@ -148,6 +148,11 @@ contract FitnessEvaluator is Test {
     ///      Chosen to be deterministic and not collide with real Base addresses.
     address internal constant IMPL_SLOT = address(uint160(uint256(keccak256("fitness.impl.slot"))));
 
+    /// @dev Must match Optimizer.CALCULATE_PARAMS_GAS_LIMIT. Candidates that exceed
+    ///      this limit would unconditionally produce bear defaults in production and
+    ///      are disqualified (fitness = 0) rather than scored against their theoretical output.
+    uint256 internal constant CALCULATE_PARAMS_GAS_LIMIT = 200_000;
+
     /// @dev Soft gas penalty: wei deducted from fitness per gas unit used by calculateParams.
     ///      Creates selection pressure toward leaner programs while keeping gas as a
     ///      secondary criterion (ETH retention still dominates).
@@ -260,6 +265,22 @@ contract FitnessEvaluator is Test {
             try Optimizer(optProxy).calculateParams(sampleInputs) returns (uint256, uint256, uint24, uint256) { } catch { }
             uint256 gasForCalcParams = gasBefore - gasleft();
 
+            // Hard disqualification: candidates that exceed the production gas cap would
+            // unconditionally produce bear defaults from getLiquidityParams() in every
+            // recenter call — equivalent to deploying the bear-defaults optimizer.
+            // Score them as 0 so the evolution pipeline never selects a program that is
+            // functionally dead on-chain.
+            if (gasForCalcParams > CALCULATE_PARAMS_GAS_LIMIT) {
+                console.log(
+                    string.concat(
+                        '{"candidate_id":"', candidateId,
+                        '","fitness":0,"error":"gas_over_limit","gas_used":', _uint2str(gasForCalcParams),
+                        "}"
+                    )
+                );
+                continue;
+            }
+
             // Score: sum lm_eth_total across all attack sequences.
             uint256 totalFitness = 0;
             Vm.DirEntry[] memory entries = vm.readDir(attacksDir);
diff --git a/tools/push3-evolution/revm-evaluator/batch-eval.sh b/tools/push3-evolution/revm-evaluator/batch-eval.sh
index 45b6357..030eb18 100755
--- a/tools/push3-evolution/revm-evaluator/batch-eval.sh
+++ b/tools/push3-evolution/revm-evaluator/batch-eval.sh
@@ -16,7 +16,9 @@
 #
 # Output (stdout):
 #   One JSON object per candidate:
-#     {"candidate_id":"gen0_c000","fitness":123456789}
+#     {"candidate_id":"gen0_c000","fitness":123456789,"gas_used":15432}
+#   Over-gas-limit candidates emit fitness:0 with "error":"gas_over_limit".
+#   Downstream parsers use the "fitness" key; extra fields are ignored.
 #
 # Exit codes:
 #   0  Success.