diff --git a/packages/format/src/types/program/context.test.ts b/packages/format/src/types/program/context.test.ts
index 47185c7ca..4470a322d 100644
--- a/packages/format/src/types/program/context.test.ts
+++ b/packages/format/src/types/program/context.test.ts
@@ -30,4 +30,20 @@ testSchemaGuards("ethdebug/format/program/context", [
     schema: "schema:ethdebug/format/program/context/frame",
     guard: Context.isFrame,
   },
+  {
+    schema: "schema:ethdebug/format/program/context/function",
+    guard: Context.Function.isIdentity,
+  },
+  {
+    schema: "schema:ethdebug/format/program/context/function/invoke",
+    guard: Context.isInvoke,
+  },
+  {
+    schema: "schema:ethdebug/format/program/context/function/return",
+    guard: Context.isReturn,
+  },
+  {
+    schema: "schema:ethdebug/format/program/context/function/revert",
+    guard: Context.isRevert,
+  },
 ] as const);
diff --git a/packages/format/src/types/program/context.ts b/packages/format/src/types/program/context.ts
index 6a552734a..9388fea7b 100644
--- a/packages/format/src/types/program/context.ts
+++ b/packages/format/src/types/program/context.ts
@@ -1,5 +1,5 @@
 import { Materials } from "#types/materials";
-import { Type, isType } from "#types/type";
+import { Type } from "#types/type";
 import { Pointer, isPointer } from "#types/pointer";
 
 export type Context =
@@ -8,7 +8,10 @@ export type Context =
   | Context.Remark
   | Context.Pick
   | Context.Gather
-  | Context.Frame;
+  | Context.Frame
+  | Context.Invoke
+  | Context.Return
+  | Context.Revert;
 
 export const isContext = (value: unknown): value is Context =>
   [
@@ -18,6 +21,9 @@ export const isContext = (value: unknown): value is Context =>
     Context.isPick,
     Context.isFrame,
     Context.isGather,
+    Context.isInvoke,
+    Context.isReturn,
+    Context.isRevert,
   ].some((guard) => guard(value));
 
 export namespace Context {
@@ -47,7 +53,7 @@ export namespace Context {
     export interface Variable {
       identifier?: string;
       declaration?: Materials.SourceRange;
-      type?: Type;
+      type?: Type.Specifier;
       pointer?: Pointer;
     }
 
@@ -66,7 +72,7 @@ export namespace Context {
       (!("identifier" in value) || typeof value.identifier === "string") &&
       (!("declaration" in value) ||
         Materials.isSourceRange(value.declaration)) &&
-      (!("type" in value) || isType(value.type)) &&
+      (!("type" in value) || Type.isSpecifier(value.type)) &&
       (!("pointer" in value) || isPointer(value.pointer));
   }
 
@@ -111,4 +117,162 @@ export namespace Context {
     !!value &&
     "frame" in value &&
     typeof value.frame === "string";
+
+  export namespace Function {
+    export interface Identity {
+      identifier?: string;
+      declaration?: Materials.SourceRange;
+      type?: Type.Specifier;
+    }
+
+    export const isIdentity = (value: unknown): value is Identity =>
+      typeof value === "object" &&
+      !!value &&
+      (!("identifier" in value) || typeof value.identifier === "string") &&
+      (!("declaration" in value) ||
+        Materials.isSourceRange(value.declaration)) &&
+      (!("type" in value) || Type.isSpecifier(value.type));
+
+    export interface PointerRef {
+      pointer: Pointer;
+    }
+
+    export const isPointerRef = (value: unknown): value is PointerRef =>
+      typeof value === "object" &&
+      !!value &&
+      "pointer" in value &&
+      isPointer(value.pointer);
+  }
+
+  export interface Invoke {
+    invoke: Invoke.Invocation;
+  }
+
+  export const isInvoke = (value: unknown): value is Invoke =>
+    typeof value === "object" &&
+    !!value &&
+    "invoke" in value &&
+    Invoke.isInvocation(value.invoke);
+
+  export namespace Invoke {
+    export type Invocation = Function.Identity &
+      (
+        | Invocation.InternalCall
+        | Invocation.ExternalCall
+        | Invocation.ContractCreation
+      );
+
+    export const isInvocation = (value: unknown): value is Invocation =>
+      Function.isIdentity(value) &&
+      (Invocation.isInternalCall(value) ||
+        Invocation.isExternalCall(value) ||
+        Invocation.isContractCreation(value));
+
+    export namespace Invocation {
+      export interface InternalCall extends Function.Identity {
+        jump: true;
+        target: Function.PointerRef;
+        arguments?: Function.PointerRef;
+      }
+
+      export const isInternalCall = (value: unknown): value is InternalCall =>
+        typeof value === "object" &&
+        !!value &&
+        "jump" in value &&
+        value.jump === true &&
+        "target" in value &&
+        Function.isPointerRef(value.target) &&
+        (!("arguments" in value) || Function.isPointerRef(value.arguments));
+
+      export interface ExternalCall extends Function.Identity {
+        message: true;
+        target: Function.PointerRef;
+        gas?: Function.PointerRef;
+        value?: Function.PointerRef;
+        input?: Function.PointerRef;
+        delegate?: true;
+        static?: true;
+      }
+
+      export const isExternalCall = (value: unknown): value is ExternalCall =>
+        typeof value === "object" &&
+        !!value &&
+        "message" in value &&
+        value.message === true &&
+        "target" in value &&
+        Function.isPointerRef(value.target) &&
+        (!("gas" in value) || Function.isPointerRef(value.gas)) &&
+        (!("value" in value) || Function.isPointerRef(value.value)) &&
+        (!("input" in value) || Function.isPointerRef(value.input)) &&
+        (!("delegate" in value) || value.delegate === true) &&
+        (!("static" in value) || value.static === true);
+
+      export interface ContractCreation extends Function.Identity {
+        create: true;
+        value?: Function.PointerRef;
+        salt?: Function.PointerRef;
+        input?: Function.PointerRef;
+      }
+
+      export const isContractCreation = (
+        value: unknown,
+      ): value is ContractCreation =>
+        typeof value === "object" &&
+        !!value &&
+        "create" in value &&
+        value.create === true &&
+        (!("value" in value) || Function.isPointerRef(value.value)) &&
+        (!("salt" in value) || Function.isPointerRef(value.salt)) &&
+        (!("input" in value) || Function.isPointerRef(value.input));
+    }
+  }
+
+  export interface Return {
+    return: Return.Info;
+  }
+
+  export const isReturn = (value: unknown): value is Return =>
+    typeof value === "object" &&
+    !!value &&
+    "return" in value &&
+    Return.isInfo(value.return);
+
+  export namespace Return {
+    export interface Info extends Function.Identity {
+      data: Function.PointerRef;
+      success?: Function.PointerRef;
+    }
+
+    export const isInfo = (value: unknown): value is Info =>
+      Function.isIdentity(value) &&
+      typeof value === "object" &&
+      !!value &&
+      "data" in value &&
+      Function.isPointerRef(value.data) &&
+      (!("success" in value) || Function.isPointerRef(value.success));
+  }
+
+  export interface Revert {
+    revert: Revert.Info;
+  }
+
+  export const isRevert = (value: unknown): value is Revert =>
+    typeof value === "object" &&
+    !!value &&
+    "revert" in value &&
+    Revert.isInfo(value.revert);
+
+  export namespace Revert {
+    export interface Info extends Function.Identity {
+      reason?: Function.PointerRef;
+      panic?: number;
+    }
+
+    export const isInfo = (value: unknown): value is Info =>
+      Function.isIdentity(value) &&
+      typeof value === "object" &&
+      !!value &&
+      (!("reason" in value) || Function.isPointerRef(value.reason)) &&
+      (!("panic" in value) || typeof value.panic === "number");
+  }
 }
diff --git a/packages/format/src/types/type/index.test.ts b/packages/format/src/types/type/index.test.ts
index 61a5349c3..cc461540a 100644
--- a/packages/format/src/types/type/index.test.ts
+++ b/packages/format/src/types/type/index.test.ts
@@ -80,4 +80,19 @@ testSchemaGuards("ethdebug/format/type", [
     schema: "schema:ethdebug/format/type/complex/struct",
     guard: Type.Complex.isStruct,
   },
+
+  // type reference and specifier
+
+  {
+    schema: "schema:ethdebug/format/type/reference",
+    guard: Type.isReference,
+  },
+  {
+    schema: "schema:ethdebug/format/type/specifier",
+    guard: Type.isSpecifier,
+  },
+  {
+    schema: "schema:ethdebug/format/type/wrapper",
+    guard: Type.isWrapper,
+  },
 ] as const);
diff --git a/packages/format/src/types/type/index.ts b/packages/format/src/types/type/index.ts
index c53d0230b..066f3a6d5 100644
--- a/packages/format/src/types/type/index.ts
+++ b/packages/format/src/types/type/index.ts
@@ -32,16 +32,30 @@ export namespace Type {
       (typeof value.contains === "object" &&
         Object.values(value.contains).every(Type.isWrapper)));
 
+  export interface Reference {
+    id: string | number;
+  }
+
+  export const isReference = (value: unknown): value is Reference =>
+    typeof value === "object" &&
+    !!value &&
+    "id" in value &&
+    (typeof value.id === "string" || typeof value.id === "number");
+
+  export type Specifier = Type | Reference;
+
+  export const isSpecifier = (value: unknown): value is Specifier =>
+    isType(value) || isReference(value);
+
   export interface Wrapper {
-    type: Type | { id: any };
+    type: Specifier;
   }
 
   export const isWrapper = (value: unknown): value is Wrapper =>
     typeof value === "object" &&
     !!value &&
     "type" in value &&
-    (isType(value.type) ||
-      (typeof value.type === "object" && !!value.type && "id" in value.type));
+    isSpecifier(value.type);
 
   export type Elementary =
     | Elementary.Uint