diff --git a/docs/reference/assignments.js b/docs/reference/assignments.js
index f774df29..a56d16a0 100644
--- a/docs/reference/assignments.js
+++ b/docs/reference/assignments.js
@@ -52,7 +52,7 @@ export const assignments = {
     ],
     fails: [
       {
-        keyword: '"NatAssign"',
+        keyword: '"NAT_NEG_ASSIGN"',
         desc: <div>when <code>a</code> (typed <code>nat</code>)is less than <code>b</code> (typed <code>nat</code>).</div>
       },
       {
diff --git a/docs/reference/declarations/entrypoint.md b/docs/reference/declarations/entrypoint.md
index e70cc32b..b60bf1ab 100644
--- a/docs/reference/declarations/entrypoint.md
+++ b/docs/reference/declarations/entrypoint.md
@@ -31,7 +31,7 @@ The body of the transaction is made of the following *sections*:
 
 ### `from`
 
-The `from` section, followed by a state value, specifies the required state of the contract to transition from. It fails with `"InvalidState"` if the transition is called while the contract is in another state.
+The `from` section, followed by a state value, specifies the required state of the contract to transition from. It fails with `"INVALID_STATE"` if the transition is called while the contract is in another state.
 
 For example:
 ```archetype
@@ -361,7 +361,7 @@ If the effect section is the only section in entry point body, the `effect` keyw
 
 ```archetype
 entry set_owner_candidate(oc : address) {
-  if caller = owner then fail("InvalidCaller");
+  if caller = owner then fail("INVALID_CALLER");
   owner_candidate := some(oc)
 }
 ```
diff --git a/docs/reference/expressions/operators/access.md b/docs/reference/expressions/operators/access.md
index 7a329b54..baf886b1 100644
--- a/docs/reference/expressions/operators/access.md
+++ b/docs/reference/expressions/operators/access.md
@@ -21,7 +21,7 @@ const b = t[2]; /* 0xbc       */
 
 Accesses value associated with key `b` in [map](/docs/language-basics/container#map) `a` (also [`big_map`](/docs/reference/types#big_map<K,%20V>) and [`iterable_big_map`](/docs/reference/types#iterable_big_map<K,%20V>)).
 
-It fails with `"NotFound"` if `b` is not found in `a`.
+It fails with `"NOT_FOUND"` if `b` is not found in `a`.
 
 For example:
 ```archetype
diff --git a/docs/reference/expressions/operators/operators.js b/docs/reference/expressions/operators/operators.js
index 4ff4a917..e9a91b98 100644
--- a/docs/reference/expressions/operators/operators.js
+++ b/docs/reference/expressions/operators/operators.js
@@ -169,6 +169,7 @@ export const operators = {
       { typa: 'int',          typb : 'int',          typr: 'rational' },
       { typa: 'duration',     typb : 'duration',     typr: 'rational' },
       { typa: 'rational',     typb : 'rational',     typr: 'rational' },
+      { typa: 'tez',          typb : 'tez',          typr: 'rational' },
     ],
     promotions: [
       { typa: 'nat',          typb : 'int',          typr: 'rational' },
diff --git a/src/components/desc/get_desc.md b/src/components/desc/get_desc.md
index 232dc53c..0c8b2ca7 100644
--- a/src/components/desc/get_desc.md
+++ b/src/components/desc/get_desc.md
@@ -18,6 +18,6 @@ It is equivalent to:
 const h =
   match ledger.get(caller) with
   | some av -> av
-  | none    -> fail(("ledger","AssetNotFound"))
+  | none    -> fail(("ledger","ASSET_NOT_FOUND"))
   end
 ```
\ No newline at end of file
diff --git a/src/components/desc/opt_get_desc.md b/src/components/desc/opt_get_desc.md
index a209d6df..27cbc4c3 100644
--- a/src/components/desc/opt_get_desc.md
+++ b/src/components/desc/opt_get_desc.md
@@ -2,6 +2,6 @@ Extracts some value from optional value `o`. It is equivalent to the following e
 ```archetype
 match o with
 | some(v) -> v
-| none -> fail("NotFound")
+| none -> fail("NOT_FOUND")
 end
 ```
\ No newline at end of file
diff --git a/src/theme/prism-archetype.js b/src/theme/prism-archetype.js
index b2c70111..f21bc46f 100644
--- a/src/theme/prism-archetype.js
+++ b/src/theme/prism-archetype.js
@@ -47,7 +47,7 @@
     	'verif': /\b(?:invariant|specification)\b/,
     	'type': /\b(?:lambda|contract|big_map|map|set|option|list|int|nat|tez|string|rational|bytes|key|key_hash|address|sapling|signature|date|duration|bool|operation|aggregate|partition|asset_view|asset_key|asset_value|iterable_big_map)\b/,
     	'constant': /\b(?:now|balance|transferred|self|caller|source|self_address|state|operations)\b/,
-		'control': /\b(?:assert|iter|begin|end|do|done|else|return|before|for|if|in|match|in|forall|added|removed|exists|then|the|from|to|while|with|InvalidCondition|InvalidCaller|NotFound|NatAssign|SliceError|DivByZero|OutOfBound)\b/,
+		'control': /\b(?:assert|iter|begin|end|do|done|else|return|before|for|if|in|match|in|forall|added|removed|exists|then|the|from|to|while|with|InvalidCondition|InvalidCaller|NotFound|NatAssign|SliceError|DIV_BY_ZERO|OUT_OF_BOUND)\b/,
 		'decl': /\b(?:const|var|let some|let)\b/,
 		'boolean': /\b(?:false|true)\b/,
     	'logic': /\b(?:and|or|=|not|asr|land|lor|lsl|lsr|lxor)\b/,