diff --git a/schemas/pointer/region/calldata.schema.yaml b/schemas/pointer/region/calldata.schema.yaml
index 25925bd2..32d6bfa7 100644
--- a/schemas/pointer/region/calldata.schema.yaml
+++ b/schemas/pointer/region/calldata.schema.yaml
@@ -20,6 +20,8 @@ allOf:
   - $ref: "schema:ethdebug/format/pointer/region/base"
   - $ref: "schema:ethdebug/format/pointer/scheme/slice"
 
+unevaluatedProperties: false
+
 examples:
   - location: calldata
     offset: "0x04"
diff --git a/schemas/pointer/region/code.schema.yaml b/schemas/pointer/region/code.schema.yaml
index bb500138..8c9723df 100644
--- a/schemas/pointer/region/code.schema.yaml
+++ b/schemas/pointer/region/code.schema.yaml
@@ -20,6 +20,8 @@ allOf:
   - $ref: "schema:ethdebug/format/pointer/region/base"
   - $ref: "schema:ethdebug/format/pointer/scheme/slice"
 
+unevaluatedProperties: false
+
 examples:
   - location: code
     offset: "0x04"
diff --git a/schemas/pointer/region/memory.schema.yaml b/schemas/pointer/region/memory.schema.yaml
index ed3d1d8d..c4474524 100644
--- a/schemas/pointer/region/memory.schema.yaml
+++ b/schemas/pointer/region/memory.schema.yaml
@@ -21,6 +21,8 @@ allOf:
   - $ref: "schema:ethdebug/format/pointer/region/base"
   - $ref: "schema:ethdebug/format/pointer/scheme/slice"
 
+unevaluatedProperties: false
+
 examples:
   - location: memory
     offset: "0x04"
diff --git a/schemas/pointer/region/returndata.schema.yaml b/schemas/pointer/region/returndata.schema.yaml
index cd1bf9cb..864c2ec7 100644
--- a/schemas/pointer/region/returndata.schema.yaml
+++ b/schemas/pointer/region/returndata.schema.yaml
@@ -20,6 +20,8 @@ allOf:
   - $ref: "schema:ethdebug/format/pointer/region/base"
   - $ref: "schema:ethdebug/format/pointer/scheme/slice"
 
+unevaluatedProperties: false
+
 examples:
   - location: returndata
     offset: "0x04"
diff --git a/schemas/pointer/region/stack.schema.yaml b/schemas/pointer/region/stack.schema.yaml
index ab220500..fd057a6c 100644
--- a/schemas/pointer/region/stack.schema.yaml
+++ b/schemas/pointer/region/stack.schema.yaml
@@ -25,6 +25,8 @@ allOf:
   - $ref: "schema:ethdebug/format/pointer/region/base"
   - $ref: "schema:ethdebug/format/pointer/scheme/segment"
 
+unevaluatedProperties: false
+
 examples:
   - location: stack
     slot: 0
diff --git a/schemas/pointer/region/storage.schema.yaml b/schemas/pointer/region/storage.schema.yaml
index 076de2b9..ca912b56 100644
--- a/schemas/pointer/region/storage.schema.yaml
+++ b/schemas/pointer/region/storage.schema.yaml
@@ -21,6 +21,7 @@ allOf:
   - $ref: "schema:ethdebug/format/pointer/region/base"
   - $ref: "schema:ethdebug/format/pointer/scheme/segment"
 
+unevaluatedProperties: false
 
 examples:
   - location: storage
diff --git a/schemas/pointer/region/transient.schema.yaml b/schemas/pointer/region/transient.schema.yaml
index f122a634..287a854c 100644
--- a/schemas/pointer/region/transient.schema.yaml
+++ b/schemas/pointer/region/transient.schema.yaml
@@ -21,6 +21,7 @@ allOf:
   - $ref: "schema:ethdebug/format/pointer/region/base"
   - $ref: "schema:ethdebug/format/pointer/scheme/segment"
 
+unevaluatedProperties: false
 
 examples:
   - location: transient
diff --git a/schemas/pointer/scheme/slice.schema.yaml b/schemas/pointer/scheme/slice.schema.yaml
index d4a6529a..7309c690 100644
--- a/schemas/pointer/scheme/slice.schema.yaml
+++ b/schemas/pointer/scheme/slice.schema.yaml
@@ -11,8 +11,13 @@ type: object
 
 properties:
   offset:
+    description: |
+      The index of the byte (starting from zero) in the data location where
+      the slice begins.
     $ref: "schema:ethdebug/format/pointer/expression"
   length:
+    description: |
+      The length of the slice in number of bytes.
     $ref: "schema:ethdebug/format/pointer/expression"
 
 required: