diff --git a/.config/dictionaries/project.dic b/.config/dictionaries/project.dic
index 7463a94cb..48c35afe0 100644
--- a/.config/dictionaries/project.dic
+++ b/.config/dictionaries/project.dic
@@ -259,6 +259,8 @@ upnp
 ureq
 userid
 utimensat
+uuidv4
+uuidv7
 UTXO
 vitss
 Vkey
diff --git a/rust/signed_doc/Cargo.toml b/rust/signed_doc/Cargo.toml
index b1c2b8430..db525033e 100644
--- a/rust/signed_doc/Cargo.toml
+++ b/rust/signed_doc/Cargo.toml
@@ -11,9 +11,6 @@ license.workspace = true
 workspace = true
 
 [dependencies]
-
-[dev-dependencies]
-clap = { version = "4.5.19",  features = ["derive", "env"] }
 anyhow = "1.0.89"
 serde = { version = "1.0.210", features = ["derive"] }
 serde_json = "1.0"
@@ -22,3 +19,6 @@ coset = "0.3.7"
 brotli = "7.0.0"
 ed25519-dalek = { version = "2.1.1", features = ["pem"] }
 uuid = { version = "1.10.0", features = ["v4", "v7", "serde"] }
+
+[dev-dependencies]
+clap = { version = "4.5.19",  features = ["derive", "env"] }
diff --git a/rust/signed_doc/examples/mk_signed_doc.rs b/rust/signed_doc/examples/mk_signed_doc.rs
index 1ed47ed04..c891fac3e 100644
--- a/rust/signed_doc/examples/mk_signed_doc.rs
+++ b/rust/signed_doc/examples/mk_signed_doc.rs
@@ -14,6 +14,7 @@ use ed25519_dalek::{
     ed25519::signature::Signer,
     pkcs8::{DecodePrivateKey, DecodePublicKey},
 };
+use signed_doc::{DocumentRef, Metadata};
 
 fn main() {
     if let Err(err) = Cli::parse().exec() {
@@ -60,26 +61,6 @@ const CONTENT_ENCODING_KEY: &str = "content encoding";
 const CONTENT_ENCODING_VALUE: &str = "br";
 const UUID_CBOR_TAG: u64 = 37;
 
-#[derive(Debug, serde::Deserialize)]
-struct Metadata {
-    r#type: uuid::Uuid,
-    id: uuid::Uuid,
-    ver: uuid::Uuid,
-    r#ref: Option<DocumentRef>,
-    template: Option<DocumentRef>,
-    reply: Option<DocumentRef>,
-    section: Option<String>,
-}
-
-#[derive(Debug, serde::Deserialize)]
-#[serde(untagged)]
-enum DocumentRef {
-    /// Reference to the latest document
-    Latest { id: uuid::Uuid },
-    /// Reference to the specific document version
-    WithVer { id: uuid::Uuid, ver: uuid::Uuid },
-}
-
 fn encode_cbor_uuid(uuid: &uuid::Uuid) -> coset::cbor::Value {
     coset::cbor::Value::Tag(
         UUID_CBOR_TAG,
diff --git a/rust/signed_doc/src/lib.rs b/rust/signed_doc/src/lib.rs
index 8ed8e7868..34330464e 100644
--- a/rust/signed_doc/src/lib.rs
+++ b/rust/signed_doc/src/lib.rs
@@ -1 +1,89 @@
 //! Catalyst documents signing crate
+use std::{convert::TryFrom, sync::Arc};
+
+/// Keep all the contents private.
+/// Better even to use a structure like this.  Wrapping in an Arc means we don't have to
+/// manage the Arc anywhere else. These are likely to be large, best to have the Arc be
+/// non-optional.
+pub struct CatalystSignedDocument {
+    /// Catalyst Signed Document metadata, raw doc, with content errors.
+    inner: Arc<InnerCatalystSignedDocument>,
+    /// Content Errors found when parsing the Document
+    content_errors: Vec<String>,
+}
+
+/// Inner type that holds the Catalyst Signed Document with parsing errors.
+struct InnerCatalystSignedDocument {
+    /// Document Metadata
+    _metadata: Metadata,
+    /// Raw payload
+    _raw_doc: Vec<u8>,
+}
+
+/// Document Metadata.
+#[derive(Debug, serde::Deserialize)]
+pub struct Metadata {
+    /// Document Type `UUIDv7`.
+    pub r#type: uuid::Uuid,
+    /// Document ID `UUIDv7`.
+    pub id: uuid::Uuid,
+    /// Document Version `UUIDv7`.
+    pub ver: uuid::Uuid,
+    /// Reference to the latest document.
+    pub r#ref: Option<DocumentRef>,
+    /// Reference to the document template.
+    pub template: Option<DocumentRef>,
+    /// Reference to the document reply.
+    pub reply: Option<DocumentRef>,
+    /// Reference to the document section.
+    pub section: Option<String>,
+}
+
+/// Reference to a Document.
+#[derive(Debug, serde::Deserialize)]
+#[serde(untagged)]
+pub enum DocumentRef {
+    /// Reference to the latest document
+    Latest {
+        /// Document ID UUID
+        id: uuid::Uuid,
+    },
+    /// Reference to the specific document version
+    WithVer {
+        /// Document ID UUID
+        id: uuid::Uuid,
+        /// Document Version UUID
+        ver: uuid::Uuid,
+    },
+}
+
+// Do this instead of `new`  if we are converting a single parameter into a struct/type we
+// should use either `From` or `TryFrom` and reserve `new` for cases where we need
+// multiple parameters to actually create the type.  This is much more elegant to use this
+// way, in code.
+impl TryFrom<Vec<u8>> for CatalystSignedDocument {
+    type Error = &'static str;
+
+    fn try_from(value: Vec<u8>) -> Result<Self, Self::Error> {
+        todo!();
+    }
+}
+
+impl CatalystSignedDocument {
+    /// Invalid Doc Type UUID
+    const INVALID_UUID: uuid::Uuid = uuid::Uuid::from_bytes([0x00; 16]);
+
+    // A bunch of getters to access the contents, or reason through the document, such as.
+
+    /// Are there any validation errors (as opposed to structural errors.
+    #[must_use]
+    pub fn has_error(&self) -> bool {
+        !self.content_errors.is_empty()
+    }
+
+    /// Return Document Type UUID.
+    #[must_use]
+    pub fn doc_type(&self) -> uuid::Uuid {
+        INVALID_UUID
+    } // Can compare it against INVALID_DOC_TYPE to see if its valid or not.
+}