diff --git a/.changeset/short-areas-spend.md b/.changeset/short-areas-spend.md
new file mode 100644
index 0000000..6d5faa5
--- /dev/null
+++ b/.changeset/short-areas-spend.md
@@ -0,0 +1,5 @@
+---
+"oxa-types": patch
+---
+
+Add initial node types using RFC0003 (Code, InlineCode, Subscript, Superscript, ThematicBreak).
diff --git a/docs/schema/block.md b/docs/schema/block.md
index 256ceb1..a99fba7 100644
--- a/docs/schema/block.md
+++ b/docs/schema/block.md
@@ -6,4 +6,4 @@
 Union of all block content types.
 
 
-Union of: @oxa:heading, @oxa:paragraph
+Union of: @oxa:code, @oxa:heading, @oxa:paragraph, @oxa:thematicbreak
diff --git a/docs/schema/code.md b/docs/schema/code.md
new file mode 100644
index 0000000..7676427
--- /dev/null
+++ b/docs/schema/code.md
@@ -0,0 +1,31 @@
+(oxa:code)=
+
+## Code
+
+
+A block of preformatted text, typically source code.
+
+
+__type__: _string_, ("Code")
+
+: The type discriminator for Code nodes.
+
+__id__: __string__
+
+: A unique identifier for the node.
+
+__classes__: __array__ ("string")
+
+: A list of class names for styling or semantics.
+
+__data__: __object__
+
+: Arbitrary key-value data attached to the node.
+
+__language__: __string__
+
+: The programming language of the code content.
+
+__value__: __string__
+
+: The code content.
diff --git a/docs/schema/inline.md b/docs/schema/inline.md
index 02a505d..d456fad 100644
--- a/docs/schema/inline.md
+++ b/docs/schema/inline.md
@@ -6,4 +6,4 @@
 Union of all inline content types.
 
 
-Union of: @oxa:text, @oxa:emphasis, @oxa:strong
+Union of: @oxa:text, @oxa:emphasis, @oxa:inlinecode, @oxa:strong, @oxa:subscript, @oxa:superscript
diff --git a/docs/schema/inlinecode.md b/docs/schema/inlinecode.md
new file mode 100644
index 0000000..b242d6d
--- /dev/null
+++ b/docs/schema/inlinecode.md
@@ -0,0 +1,31 @@
+(oxa:inlinecode)=
+
+## InlineCode
+
+
+Short fragments of code appearing within prose.
+
+
+__type__: _string_, ("InlineCode")
+
+: The type discriminator for InlineCode nodes.
+
+__id__: __string__
+
+: A unique identifier for the node.
+
+__classes__: __array__ ("string")
+
+: A list of class names for styling or semantics.
+
+__data__: __object__
+
+: Arbitrary key-value data attached to the node.
+
+__language__: __string__
+
+: The programming language of the code content.
+
+__value__: __string__
+
+: The code content.
diff --git a/docs/schema/subscript.md b/docs/schema/subscript.md
new file mode 100644
index 0000000..3dce0aa
--- /dev/null
+++ b/docs/schema/subscript.md
@@ -0,0 +1,28 @@
+(oxa:subscript)=
+
+## Subscript
+
+
+Content rendered below the baseline (e.g. chemical formulae, variable indices).
+
+
+__type__: _string_, ("Subscript")
+
+: The type discriminator for Subscript nodes.
+
+__id__: __string__
+
+: A unique identifier for the node.
+
+__classes__: __array__ ("string")
+
+: A list of class names for styling or semantics.
+
+__data__: __object__
+
+: Arbitrary key-value data attached to the node.
+
+__children__: __array__ ("Inline")
+
+: The inline content to render as subscript.
+: See @oxa:inline
diff --git a/docs/schema/superscript.md b/docs/schema/superscript.md
new file mode 100644
index 0000000..fd539a1
--- /dev/null
+++ b/docs/schema/superscript.md
@@ -0,0 +1,28 @@
+(oxa:superscript)=
+
+## Superscript
+
+
+Content rendered above the baseline (e.g. exponents, ordinal suffixes).
+
+
+__type__: _string_, ("Superscript")
+
+: The type discriminator for Superscript nodes.
+
+__id__: __string__
+
+: A unique identifier for the node.
+
+__classes__: __array__ ("string")
+
+: A list of class names for styling or semantics.
+
+__data__: __object__
+
+: Arbitrary key-value data attached to the node.
+
+__children__: __array__ ("Inline")
+
+: The inline content to render as superscript.
+: See @oxa:inline
diff --git a/docs/schema/thematicbreak.md b/docs/schema/thematicbreak.md
new file mode 100644
index 0000000..30df4a1
--- /dev/null
+++ b/docs/schema/thematicbreak.md
@@ -0,0 +1,23 @@
+(oxa:thematicbreak)=
+
+## ThematicBreak
+
+
+A thematic or structural division between sections of content.
+
+
+__type__: _string_, ("ThematicBreak")
+
+: The type discriminator for ThematicBreak nodes.
+
+__id__: __string__
+
+: A unique identifier for the node.
+
+__classes__: __array__ ("string")
+
+: A list of class names for styling or semantics.
+
+__data__: __object__
+
+: Arbitrary key-value data attached to the node.
diff --git a/packages/oxa-types-py/src/oxa_types/__init__.py b/packages/oxa-types-py/src/oxa_types/__init__.py
index 254ca85..1a21899 100644
--- a/packages/oxa-types-py/src/oxa_types/__init__.py
+++ b/packages/oxa-types-py/src/oxa_types/__init__.py
@@ -12,6 +12,27 @@
 from pydantic import BaseModel, ConfigDict, Field
 
 
+class Code(BaseModel):
+    """A block of preformatted text, typically source code."""
+
+    model_config = ConfigDict(strict=True)
+
+    type: Literal["Code"] = "Code"
+    id: str | None = Field(
+        default=None, description="A unique identifier for the node."
+    )
+    classes: list[str] | None = Field(
+        default=None, description="A list of class names for styling or semantics."
+    )
+    data: dict[str, Any] | None = Field(
+        default=None, description="Arbitrary key-value data attached to the node."
+    )
+    language: str | None = Field(
+        default=None, description="The programming language of the code content."
+    )
+    value: str = Field(description="The code content.")
+
+
 class Document(BaseModel):
     """A document with metadata, title, and block content."""
 
@@ -73,6 +94,27 @@ class Heading(BaseModel):
     children: list["Inline"] = Field(description="The inline content of the heading.")
 
 
+class InlineCode(BaseModel):
+    """Short fragments of code appearing within prose."""
+
+    model_config = ConfigDict(strict=True)
+
+    type: Literal["InlineCode"] = "InlineCode"
+    id: str | None = Field(
+        default=None, description="A unique identifier for the node."
+    )
+    classes: list[str] | None = Field(
+        default=None, description="A list of class names for styling or semantics."
+    )
+    data: dict[str, Any] | None = Field(
+        default=None, description="Arbitrary key-value data attached to the node."
+    )
+    language: str | None = Field(
+        default=None, description="The programming language of the code content."
+    )
+    value: str = Field(description="The code content.")
+
+
 class Paragraph(BaseModel):
     """A paragraph of inline content."""
 
@@ -109,6 +151,46 @@ class Strong(BaseModel):
     children: list["Inline"] = Field(description="The inline content to emphasize.")
 
 
+class Subscript(BaseModel):
+    """Content rendered below the baseline (e.g. chemical formulae, variable indices)."""
+
+    model_config = ConfigDict(strict=True)
+
+    type: Literal["Subscript"] = "Subscript"
+    id: str | None = Field(
+        default=None, description="A unique identifier for the node."
+    )
+    classes: list[str] | None = Field(
+        default=None, description="A list of class names for styling or semantics."
+    )
+    data: dict[str, Any] | None = Field(
+        default=None, description="Arbitrary key-value data attached to the node."
+    )
+    children: list["Inline"] = Field(
+        description="The inline content to render as subscript."
+    )
+
+
+class Superscript(BaseModel):
+    """Content rendered above the baseline (e.g. exponents, ordinal suffixes)."""
+
+    model_config = ConfigDict(strict=True)
+
+    type: Literal["Superscript"] = "Superscript"
+    id: str | None = Field(
+        default=None, description="A unique identifier for the node."
+    )
+    classes: list[str] | None = Field(
+        default=None, description="A list of class names for styling or semantics."
+    )
+    data: dict[str, Any] | None = Field(
+        default=None, description="Arbitrary key-value data attached to the node."
+    )
+    children: list["Inline"] = Field(
+        description="The inline content to render as superscript."
+    )
+
+
 class Text(BaseModel):
     """A text node containing a string value."""
 
@@ -127,30 +209,62 @@ class Text(BaseModel):
     value: str = Field(description="The text content.")
 
 
+class ThematicBreak(BaseModel):
+    """A thematic or structural division between sections of content."""
+
+    model_config = ConfigDict(strict=True)
+
+    type: Literal["ThematicBreak"] = "ThematicBreak"
+    id: str | None = Field(
+        default=None, description="A unique identifier for the node."
+    )
+    classes: list[str] | None = Field(
+        default=None, description="A list of class names for styling or semantics."
+    )
+    data: dict[str, Any] | None = Field(
+        default=None, description="Arbitrary key-value data attached to the node."
+    )
+
+
 # Union of all block content types.
-Block = Annotated[Union[Heading, Paragraph], Field(discriminator="type")]
+Block = Annotated[
+    Union[Code, Heading, Paragraph, ThematicBreak], Field(discriminator="type")
+]
 
 
 # Union of all inline content types.
-Inline = Annotated[Union[Text, Emphasis, Strong], Field(discriminator="type")]
+Inline = Annotated[
+    Union[Text, Emphasis, InlineCode, Strong, Subscript, Superscript],
+    Field(discriminator="type"),
+]
 
 
 # Rebuild models to resolve forward references
+Code.model_rebuild()
 Document.model_rebuild()
 Emphasis.model_rebuild()
 Heading.model_rebuild()
+InlineCode.model_rebuild()
 Paragraph.model_rebuild()
 Strong.model_rebuild()
+Subscript.model_rebuild()
+Superscript.model_rebuild()
 Text.model_rebuild()
+ThematicBreak.model_rebuild()
 
 
 __all__ = [
     "Block",
+    "Code",
     "Document",
     "Emphasis",
     "Heading",
     "Inline",
+    "InlineCode",
     "Paragraph",
     "Strong",
+    "Subscript",
+    "Superscript",
     "Text",
+    "ThematicBreak",
 ]
diff --git a/packages/oxa-types-rs/src/lib.rs b/packages/oxa-types-rs/src/lib.rs
index ca3d749..8baaa4f 100644
--- a/packages/oxa-types-rs/src/lib.rs
+++ b/packages/oxa-types-rs/src/lib.rs
@@ -9,6 +9,27 @@
 use monostate::MustBe;
 use serde::{Deserialize, Serialize};
 
+/// A block of preformatted text, typically source code.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Code {
+    /// The type discriminator for Code nodes.
+    pub r#type: MustBe!("Code"),
+    /// A unique identifier for the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<String>,
+    /// A list of class names for styling or semantics.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub classes: Option<Vec<String>>,
+    /// Arbitrary key-value data attached to the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub data: Option<serde_json::Value>,
+    /// The programming language of the code content.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub language: Option<String>,
+    /// The code content.
+    pub value: String,
+}
+
 /// A document with metadata, title, and block content.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct Document {
@@ -71,6 +92,27 @@ pub struct Heading {
     pub children: Vec<Inline>,
 }
 
+/// Short fragments of code appearing within prose.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct InlineCode {
+    /// The type discriminator for InlineCode nodes.
+    pub r#type: MustBe!("InlineCode"),
+    /// A unique identifier for the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<String>,
+    /// A list of class names for styling or semantics.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub classes: Option<Vec<String>>,
+    /// Arbitrary key-value data attached to the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub data: Option<serde_json::Value>,
+    /// The programming language of the code content.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub language: Option<String>,
+    /// The code content.
+    pub value: String,
+}
+
 /// A paragraph of inline content.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct Paragraph {
@@ -107,6 +149,42 @@ pub struct Strong {
     pub children: Vec<Inline>,
 }
 
+/// Content rendered below the baseline (e.g. chemical formulae, variable indices).
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Subscript {
+    /// The type discriminator for Subscript nodes.
+    pub r#type: MustBe!("Subscript"),
+    /// A unique identifier for the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<String>,
+    /// A list of class names for styling or semantics.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub classes: Option<Vec<String>>,
+    /// Arbitrary key-value data attached to the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub data: Option<serde_json::Value>,
+    /// The inline content to render as subscript.
+    pub children: Vec<Inline>,
+}
+
+/// Content rendered above the baseline (e.g. exponents, ordinal suffixes).
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Superscript {
+    /// The type discriminator for Superscript nodes.
+    pub r#type: MustBe!("Superscript"),
+    /// A unique identifier for the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<String>,
+    /// A list of class names for styling or semantics.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub classes: Option<Vec<String>>,
+    /// Arbitrary key-value data attached to the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub data: Option<serde_json::Value>,
+    /// The inline content to render as superscript.
+    pub children: Vec<Inline>,
+}
+
 /// A text node containing a string value.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct Text {
@@ -125,12 +203,30 @@ pub struct Text {
     pub value: String,
 }
 
+/// A thematic or structural division between sections of content.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct ThematicBreak {
+    /// The type discriminator for ThematicBreak nodes.
+    pub r#type: MustBe!("ThematicBreak"),
+    /// A unique identifier for the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<String>,
+    /// A list of class names for styling or semantics.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub classes: Option<Vec<String>>,
+    /// Arbitrary key-value data attached to the node.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub data: Option<serde_json::Value>,
+}
+
 /// Union of all block content types.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(untagged)]
 pub enum Block {
+    Code(Code),
     Heading(Heading),
     Paragraph(Paragraph),
+    ThematicBreak(ThematicBreak),
 }
 
 /// Union of all inline content types.
@@ -139,5 +235,8 @@ pub enum Block {
 pub enum Inline {
     Text(Text),
     Emphasis(Emphasis),
+    InlineCode(InlineCode),
     Strong(Strong),
+    Subscript(Subscript),
+    Superscript(Superscript),
 }
diff --git a/packages/oxa-types-ts/src/index.ts b/packages/oxa-types-ts/src/index.ts
index e2f2b80..ec47e2d 100644
--- a/packages/oxa-types-ts/src/index.ts
+++ b/packages/oxa-types-ts/src/index.ts
@@ -5,6 +5,36 @@
  * in the schema/ directory and run `pnpm codegen ts`.
  */
 
+/**
+ * A block of preformatted text, typically source code.
+ */
+export interface Code {
+  /**
+   * The type discriminator for Code nodes.
+   */
+  type: "Code";
+  /**
+   * A unique identifier for the node.
+   */
+  id?: string;
+  /**
+   * A list of class names for styling or semantics.
+   */
+  classes?: string[];
+  /**
+   * Arbitrary key-value data attached to the node.
+   */
+  data?: Record<string, unknown>;
+  /**
+   * The programming language of the code content.
+   */
+  language?: string;
+  /**
+   * The code content.
+   */
+  value: string;
+}
+
 /**
  * A document with metadata, title, and block content.
  */
@@ -95,6 +125,36 @@ export interface Heading {
   children: Inline[];
 }
 
+/**
+ * Short fragments of code appearing within prose.
+ */
+export interface InlineCode {
+  /**
+   * The type discriminator for InlineCode nodes.
+   */
+  type: "InlineCode";
+  /**
+   * A unique identifier for the node.
+   */
+  id?: string;
+  /**
+   * A list of class names for styling or semantics.
+   */
+  classes?: string[];
+  /**
+   * Arbitrary key-value data attached to the node.
+   */
+  data?: Record<string, unknown>;
+  /**
+   * The programming language of the code content.
+   */
+  language?: string;
+  /**
+   * The code content.
+   */
+  value: string;
+}
+
 /**
  * A paragraph of inline content.
  */
@@ -147,6 +207,58 @@ export interface Strong {
   children: Inline[];
 }
 
+/**
+ * Content rendered below the baseline (e.g. chemical formulae, variable indices).
+ */
+export interface Subscript {
+  /**
+   * The type discriminator for Subscript nodes.
+   */
+  type: "Subscript";
+  /**
+   * A unique identifier for the node.
+   */
+  id?: string;
+  /**
+   * A list of class names for styling or semantics.
+   */
+  classes?: string[];
+  /**
+   * Arbitrary key-value data attached to the node.
+   */
+  data?: Record<string, unknown>;
+  /**
+   * The inline content to render as subscript.
+   */
+  children: Inline[];
+}
+
+/**
+ * Content rendered above the baseline (e.g. exponents, ordinal suffixes).
+ */
+export interface Superscript {
+  /**
+   * The type discriminator for Superscript nodes.
+   */
+  type: "Superscript";
+  /**
+   * A unique identifier for the node.
+   */
+  id?: string;
+  /**
+   * A list of class names for styling or semantics.
+   */
+  classes?: string[];
+  /**
+   * Arbitrary key-value data attached to the node.
+   */
+  data?: Record<string, unknown>;
+  /**
+   * The inline content to render as superscript.
+   */
+  children: Inline[];
+}
+
 /**
  * A text node containing a string value.
  */
@@ -173,12 +285,40 @@ export interface Text {
   value: string;
 }
 
+/**
+ * A thematic or structural division between sections of content.
+ */
+export interface ThematicBreak {
+  /**
+   * The type discriminator for ThematicBreak nodes.
+   */
+  type: "ThematicBreak";
+  /**
+   * A unique identifier for the node.
+   */
+  id?: string;
+  /**
+   * A list of class names for styling or semantics.
+   */
+  classes?: string[];
+  /**
+   * Arbitrary key-value data attached to the node.
+   */
+  data?: Record<string, unknown>;
+}
+
 /**
  * Union of all block content types.
  */
-export type Block = Heading | Paragraph;
+export type Block = Code | Heading | Paragraph | ThematicBreak;
 
 /**
  * Union of all inline content types.
  */
-export type Inline = Text | Emphasis | Strong;
+export type Inline =
+  | Text
+  | Emphasis
+  | InlineCode
+  | Strong
+  | Subscript
+  | Superscript;
diff --git a/schema/Block.yaml b/schema/Block.yaml
index 90468b0..7b0250f 100644
--- a/schema/Block.yaml
+++ b/schema/Block.yaml
@@ -3,5 +3,7 @@ $id: Block
 title: Block
 description: Union of all block content types.
 anyOf:
+  - $ref: "./Code.yaml"
   - $ref: "./Heading.yaml"
   - $ref: "./Paragraph.yaml"
+  - $ref: "./ThematicBreak.yaml"
diff --git a/schema/Code.yaml b/schema/Code.yaml
new file mode 100644
index 0000000..09fa6b6
--- /dev/null
+++ b/schema/Code.yaml
@@ -0,0 +1,30 @@
+$schema: "http://json-schema.org/draft-07/schema#"
+$id: Code
+title: Code
+description: A block of preformatted text, typically source code.
+type: object
+properties:
+  type:
+    description: The type discriminator for Code nodes.
+    enum: [Code]
+  id:
+    description: A unique identifier for the node.
+    type: string
+  classes:
+    description: A list of class names for styling or semantics.
+    type: array
+    items:
+      type: string
+  data:
+    description: Arbitrary key-value data attached to the node.
+    type: object
+    additionalProperties: true
+  language:
+    description: The programming language of the code content.
+    type: string
+  value:
+    description: The code content.
+    type: string
+required:
+  - type
+  - value
diff --git a/schema/Inline.yaml b/schema/Inline.yaml
index b2bb034..8fbc330 100644
--- a/schema/Inline.yaml
+++ b/schema/Inline.yaml
@@ -5,4 +5,7 @@ description: Union of all inline content types.
 anyOf:
   - $ref: "./Text.yaml"
   - $ref: "./Emphasis.yaml"
+  - $ref: "./InlineCode.yaml"
   - $ref: "./Strong.yaml"
+  - $ref: "./Subscript.yaml"
+  - $ref: "./Superscript.yaml"
diff --git a/schema/InlineCode.yaml b/schema/InlineCode.yaml
new file mode 100644
index 0000000..52b9583
--- /dev/null
+++ b/schema/InlineCode.yaml
@@ -0,0 +1,30 @@
+$schema: "http://json-schema.org/draft-07/schema#"
+$id: InlineCode
+title: InlineCode
+description: Short fragments of code appearing within prose.
+type: object
+properties:
+  type:
+    description: The type discriminator for InlineCode nodes.
+    enum: [InlineCode]
+  id:
+    description: A unique identifier for the node.
+    type: string
+  classes:
+    description: A list of class names for styling or semantics.
+    type: array
+    items:
+      type: string
+  data:
+    description: Arbitrary key-value data attached to the node.
+    type: object
+    additionalProperties: true
+  language:
+    description: The programming language of the code content.
+    type: string
+  value:
+    description: The code content.
+    type: string
+required:
+  - type
+  - value
diff --git a/schema/Subscript.yaml b/schema/Subscript.yaml
new file mode 100644
index 0000000..f202750
--- /dev/null
+++ b/schema/Subscript.yaml
@@ -0,0 +1,29 @@
+$schema: "http://json-schema.org/draft-07/schema#"
+$id: Subscript
+title: Subscript
+description: Content rendered below the baseline (e.g. chemical formulae, variable indices).
+type: object
+properties:
+  type:
+    description: The type discriminator for Subscript nodes.
+    enum: [Subscript]
+  id:
+    description: A unique identifier for the node.
+    type: string
+  classes:
+    description: A list of class names for styling or semantics.
+    type: array
+    items:
+      type: string
+  data:
+    description: Arbitrary key-value data attached to the node.
+    type: object
+    additionalProperties: true
+  children:
+    description: The inline content to render as subscript.
+    type: array
+    items:
+      $ref: "./Inline.yaml"
+required:
+  - type
+  - children
diff --git a/schema/Superscript.yaml b/schema/Superscript.yaml
new file mode 100644
index 0000000..2fbe2d0
--- /dev/null
+++ b/schema/Superscript.yaml
@@ -0,0 +1,29 @@
+$schema: "http://json-schema.org/draft-07/schema#"
+$id: Superscript
+title: Superscript
+description: Content rendered above the baseline (e.g. exponents, ordinal suffixes).
+type: object
+properties:
+  type:
+    description: The type discriminator for Superscript nodes.
+    enum: [Superscript]
+  id:
+    description: A unique identifier for the node.
+    type: string
+  classes:
+    description: A list of class names for styling or semantics.
+    type: array
+    items:
+      type: string
+  data:
+    description: Arbitrary key-value data attached to the node.
+    type: object
+    additionalProperties: true
+  children:
+    description: The inline content to render as superscript.
+    type: array
+    items:
+      $ref: "./Inline.yaml"
+required:
+  - type
+  - children
diff --git a/schema/ThematicBreak.yaml b/schema/ThematicBreak.yaml
new file mode 100644
index 0000000..4c3891a
--- /dev/null
+++ b/schema/ThematicBreak.yaml
@@ -0,0 +1,23 @@
+$schema: "http://json-schema.org/draft-07/schema#"
+$id: ThematicBreak
+title: ThematicBreak
+description: A thematic or structural division between sections of content.
+type: object
+properties:
+  type:
+    description: The type discriminator for ThematicBreak nodes.
+    enum: [ThematicBreak]
+  id:
+    description: A unique identifier for the node.
+    type: string
+  classes:
+    description: A list of class names for styling or semantics.
+    type: array
+    items:
+      type: string
+  data:
+    description: Arbitrary key-value data attached to the node.
+    type: object
+    additionalProperties: true
+required:
+  - type
diff --git a/schema/schema.json b/schema/schema.json
index db84d07..97a723d 100644
--- a/schema/schema.json
+++ b/schema/schema.json
@@ -9,14 +9,56 @@
       "title": "Block",
       "description": "Union of all block content types.",
       "anyOf": [
+        {
+          "$ref": "#/definitions/Code"
+        },
         {
           "$ref": "#/definitions/Heading"
         },
         {
           "$ref": "#/definitions/Paragraph"
+        },
+        {
+          "$ref": "#/definitions/ThematicBreak"
         }
       ]
     },
+    "Code": {
+      "title": "Code",
+      "description": "A block of preformatted text, typically source code.",
+      "type": "object",
+      "properties": {
+        "type": {
+          "description": "The type discriminator for Code nodes.",
+          "enum": ["Code"]
+        },
+        "id": {
+          "description": "A unique identifier for the node.",
+          "type": "string"
+        },
+        "classes": {
+          "description": "A list of class names for styling or semantics.",
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "data": {
+          "description": "Arbitrary key-value data attached to the node.",
+          "type": "object",
+          "additionalProperties": true
+        },
+        "language": {
+          "description": "The programming language of the code content.",
+          "type": "string"
+        },
+        "value": {
+          "description": "The code content.",
+          "type": "string"
+        }
+      },
+      "required": ["type", "value"]
+    },
     "Document": {
       "title": "Document",
       "description": "A document with metadata, title, and block content.",
@@ -150,11 +192,56 @@
         {
           "$ref": "#/definitions/Emphasis"
         },
+        {
+          "$ref": "#/definitions/InlineCode"
+        },
         {
           "$ref": "#/definitions/Strong"
+        },
+        {
+          "$ref": "#/definitions/Subscript"
+        },
+        {
+          "$ref": "#/definitions/Superscript"
         }
       ]
     },
+    "InlineCode": {
+      "title": "InlineCode",
+      "description": "Short fragments of code appearing within prose.",
+      "type": "object",
+      "properties": {
+        "type": {
+          "description": "The type discriminator for InlineCode nodes.",
+          "enum": ["InlineCode"]
+        },
+        "id": {
+          "description": "A unique identifier for the node.",
+          "type": "string"
+        },
+        "classes": {
+          "description": "A list of class names for styling or semantics.",
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "data": {
+          "description": "Arbitrary key-value data attached to the node.",
+          "type": "object",
+          "additionalProperties": true
+        },
+        "language": {
+          "description": "The programming language of the code content.",
+          "type": "string"
+        },
+        "value": {
+          "description": "The code content.",
+          "type": "string"
+        }
+      },
+      "required": ["type", "value"]
+    },
     "Paragraph": {
       "title": "Paragraph",
       "description": "A paragraph of inline content.",
@@ -225,6 +312,76 @@
       },
       "required": ["type", "children"]
     },
+    "Subscript": {
+      "title": "Subscript",
+      "description": "Content rendered below the baseline (e.g. chemical formulae, variable indices).",
+      "type": "object",
+      "properties": {
+        "type": {
+          "description": "The type discriminator for Subscript nodes.",
+          "enum": ["Subscript"]
+        },
+        "id": {
+          "description": "A unique identifier for the node.",
+          "type": "string"
+        },
+        "classes": {
+          "description": "A list of class names for styling or semantics.",
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "data": {
+          "description": "Arbitrary key-value data attached to the node.",
+          "type": "object",
+          "additionalProperties": true
+        },
+        "children": {
+          "description": "The inline content to render as subscript.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/Inline"
+          }
+        }
+      },
+      "required": ["type", "children"]
+    },
+    "Superscript": {
+      "title": "Superscript",
+      "description": "Content rendered above the baseline (e.g. exponents, ordinal suffixes).",
+      "type": "object",
+      "properties": {
+        "type": {
+          "description": "The type discriminator for Superscript nodes.",
+          "enum": ["Superscript"]
+        },
+        "id": {
+          "description": "A unique identifier for the node.",
+          "type": "string"
+        },
+        "classes": {
+          "description": "A list of class names for styling or semantics.",
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "data": {
+          "description": "Arbitrary key-value data attached to the node.",
+          "type": "object",
+          "additionalProperties": true
+        },
+        "children": {
+          "description": "The inline content to render as superscript.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/Inline"
+          }
+        }
+      },
+      "required": ["type", "children"]
+    },
     "Text": {
       "title": "Text",
       "description": "A text node containing a string value.",
@@ -256,6 +413,34 @@
         }
       },
       "required": ["type", "value"]
+    },
+    "ThematicBreak": {
+      "title": "ThematicBreak",
+      "description": "A thematic or structural division between sections of content.",
+      "type": "object",
+      "properties": {
+        "type": {
+          "description": "The type discriminator for ThematicBreak nodes.",
+          "enum": ["ThematicBreak"]
+        },
+        "id": {
+          "description": "A unique identifier for the node.",
+          "type": "string"
+        },
+        "classes": {
+          "description": "A list of class names for styling or semantics.",
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
+        },
+        "data": {
+          "description": "Arbitrary key-value data attached to the node.",
+          "type": "object",
+          "additionalProperties": true
+        }
+      },
+      "required": ["type"]
     }
   },
   "$ref": "#/definitions/Document"