diff --git a/beacon_chain.nimble b/beacon_chain.nimble
index cedf249f5..0abca462d 100644
--- a/beacon_chain.nimble
+++ b/beacon_chain.nimble
@@ -23,8 +23,7 @@ requires "nim >= 0.18.0",
   "confutils",
   "serialization",
   "json_serialization",
-  "json_rpc",
-  "cligen 0.9.18"
+  "json_rpc"
 
 ### Helper functions
 proc test(name: string, defaultLang = "c") =
diff --git a/beacon_chain/validator_keygen.nim b/beacon_chain/validator_keygen.nim
index e314e1f54..1558408c5 100644
--- a/beacon_chain/validator_keygen.nim
+++ b/beacon_chain/validator_keygen.nim
@@ -1,6 +1,6 @@
 import
   os, ospaths, strutils, strformat,
-  asyncdispatch2, milagro_crypto, nimcrypto, json_serialization,
+  asyncdispatch2, milagro_crypto, nimcrypto, json_serialization, confutils,
   spec/[datatypes, digest, crypto], conf, randao, time, ssz,
   ../tests/testutil
 
@@ -20,9 +20,6 @@ proc genSingleValidator(path: string): (ValidatorPubKey,
 
   return (v.privKey.pubKey(), v.privKey, v.randao.initialCommitment)
 
-proc printUsage() =
-  echo "Usage: validator_keygen <number-of-validators> <out-path>"
-
 # TODO: Make these more comprehensive and find them a new home
 type
   Ether* = distinct int64
@@ -31,24 +28,20 @@ type
 template eth*(x: SomeInteger): Ether = Ether(x)
 template gwei*(x: Ether): Gwei = Gwei(int(x) * 1000000000)
 
-proc main() =
-  if paramCount() != 2:
-    printUsage()
-    return
+cli do (validators: int,
+        outputDir: string,
+        startupDelay = 0):
 
-  let totalValidators = parseInt paramStr(1)
-  if totalValidators < 64:
+  if validators < 64:
     echo "The number of validators must be higher than ", EPOCH_LENGTH, " (EPOCH_LENGTH)"
     echo "There must be at least one validator assigned per slot."
     quit 1
 
-  let outPath = paramStr(2)
-
   var startupData: ChainStartupData
 
-  for i in 1 .. totalValidators:
+  for i in 1 .. validators:
     let (pubKey, privKey, randaoCommitment) =
-      genSingleValidator(outPath / &"validator-{i:02}.json")
+      genSingleValidator(outputDir / &"validator-{i:02}.json")
 
     let
       withdrawalCredentials = makeFakeHash(i)
@@ -71,10 +64,7 @@ proc main() =
           withdrawal_credentials: withdrawalCredentials,
           randao_commitment: randaoCommitment)))
 
-  startupData.genesisTime = (now() div 1000)
+  startupData.genesisTime = uint64(int(now() div 1000) + startupDelay)
 
-  writeFile(outPath / "startup.json", startupData)
-
-when isMainModule:
-  main()
+  writeFile(outputDir / "startup.json", startupData)
 
diff --git a/research/serialized_sizes.nim b/research/serialized_sizes.nim
index 033cd3a73..c879b10b9 100644
--- a/research/serialized_sizes.nim
+++ b/research/serialized_sizes.nim
@@ -1,8 +1,8 @@
 import
+  confutils,
   ../beacon_chain/[extras, ssz],
   ../beacon_chain/spec/[beaconstate, datatypes, digest],
-  ../tests/testutil,
-  cligen
+  ../tests/testutil
 
 proc stateSize(deposits: int, maxContent = false) =
   var state = get_initial_beacon_state(
diff --git a/research/state_sim.nim b/research/state_sim.nim
index f4a4dd947..71016721f 100644
--- a/research/state_sim.nim
+++ b/research/state_sim.nim
@@ -1,5 +1,5 @@
 import
-  cligen,
+  confutils,
   json, strformat,
   options, sequtils, random,
   milagro_crypto,
@@ -17,13 +17,12 @@ proc writeJson*(prefix, slot, v: auto) =
   discard open(f, fmt"{prefix:04}-{slot:08}.json", fmWrite)
   write(f, pretty(%*(v)))
 
-proc transition(
-    slots = 1945,
-    validators = EPOCH_LENGTH, # One per shard is minimum
-    json_interval = EPOCH_LENGTH,
-    prefix = 0,
-    attesterRatio = 0.0,
-    validate = false) =
+cli do(slots = 1945,
+       validators = EPOCH_LENGTH, # One per shard is minimum
+       json_interval = EPOCH_LENGTH,
+       prefix = 0,
+       attesterRatio {.desc: "ratio of validators that attest in each round"} = 0.0,
+       validate = false):
   let
     flags = if validate: {} else: {skipValidation}
     genesisState = get_initial_beacon_state(
@@ -84,7 +83,3 @@ proc transition(
 
   echo "done!"
 
-dispatch(
-  transition,
-  help = { "attesterRatio": "ratio of validators that attest in each round" }
-)
diff --git a/tests/simulation/start.sh b/tests/simulation/start.sh
index 9742b4e8f..482743947 100755
--- a/tests/simulation/start.sh
+++ b/tests/simulation/start.sh
@@ -29,7 +29,7 @@ if [[ -z "$SKIP_BUILDS" ]]; then
 fi
 
 if [ ! -f $STARTUP_FILE ]; then
-  $VALIDATOR_KEYGEN_BIN $NUMBER_OF_VALIDATORS "$SIMULATION_DIR"
+  $VALIDATOR_KEYGEN_BIN --validators=$NUMBER_OF_VALIDATORS --outputDir="$SIMULATION_DIR"
 fi
 
 if [ ! -f $SNAPSHOT_FILE ]; then