diff --git a/json/src/spec/spec.rs b/json/src/spec/spec.rs
index e48134270..b8597987a 100644
--- a/json/src/spec/spec.rs
+++ b/json/src/spec/spec.rs
@@ -24,17 +24,29 @@ use serde_json::Error;
 /// Fork spec definition
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Deserialize)]
 pub enum ForkSpec {
+	/// EIP 150 Tangerine Whistle: Gas cost changes for IO-heavy operations (#2,463,000, 2016-10-18)
 	EIP150,
+	/// EIP 158/EIP 161 Spurious Dragon: State trie clearing (#2,675,000, 2016-11-22)
 	EIP158,
+	/// Frontier (#1, 2015-07-30)
 	Frontier,
+	/// Homestead (#1,150,000, 2016-03-14)
 	Homestead,
+	/// Byzantium Metropolis phase 1 (#4,370,000, 2017-10-16)
 	Byzantium,
+	/// Constantinople Metropolis phase 2 (#7,280,000, 2019-02-28)
 	Constantinople,
+	/// Constantinople transition test-net
 	ConstantinopleFix,
+	/// Istanbul (To be announced)
 	Istanbul,
+	/// Byzantium transition test-net
 	EIP158ToByzantiumAt5,
+	/// Homestead transition test-net
 	FrontierToHomesteadAt5,
+	/// Homestead transition test-net
 	HomesteadToDaoAt5,
+	/// EIP158/EIP161 transition test-net
 	HomesteadToEIP150At5,
 }