diff --git a/contracts/multisig-account/src/lib.rs b/contracts/multisig-account/src/lib.rs
index 50b0a48..1e0f19d 100644
--- a/contracts/multisig-account/src/lib.rs
+++ b/contracts/multisig-account/src/lib.rs
@@ -15,23 +15,34 @@ enum DataKey {
     SignerCount,
 }
 
+/// A single ed25519 signature from one signer in the multisig set.
 #[contracttype]
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct Signature {
+    /// The public key of the signer who created this signature.
     pub public_key: BytesN<32>,
+    /// The ed25519 signature bytes.
     pub signature: BytesN<64>,
 }
 
+/// Errors returned by the multisig-account contract's public entry points.
 #[contracterror]
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 #[repr(u32)]
 pub enum Error {
+    /// The configured threshold is zero or exceeds the signer count.
     InvalidThreshold = 1,
+    /// The signer configuration contains duplicate public keys.
     DuplicateSigner = 2,
+    /// The supplied signature count is below the configured threshold.
     NotEnoughSigners = 3,
+    /// Signatures are not strictly ordered by ascending public key.
     BadSignatureOrder = 4,
+    /// A signature corresponds to a public key that is not a configured signer.
     UnknownSigner = 5,
+    /// The contract has not been initialized; threshold or signer count is unavailable.
     NotInitialized = 6,
+    /// The supplied signature count exceeds the configured signer count.
     TooManySigners = 7,
 }
 
@@ -46,6 +57,11 @@ pub struct MultisigAccount;
 
 #[contractimpl]
 impl MultisigAccount {
+    /// Initialize the multisig account with a set of authorized signers and a signature threshold.
+    ///
+    /// # Arguments
+    /// * `signers` — A vector of ed25519 public keys (32 bytes each) authorized to sign transactions.
+    /// * `threshold` — The minimum number of signatures required to authorize a transaction; must be > 0 and ≤ the signer count.
     pub fn __constructor(env: Env, signers: Vec<BytesN<32>>, threshold: u32) {
         if threshold == 0 || threshold > signers.len() {
             panic_with_error!(&env, Error::InvalidThreshold);
@@ -73,6 +89,15 @@ impl CustomAccountInterface for MultisigAccount {
     type Signature = Vec<Signature>;
     type Error = Error;
 
+    /// Verify the authorization of a transaction by checking N-of-M ed25519 signatures.
+    ///
+    /// Verifies that the supplied signatures meet the configured threshold and each belongs to
+    /// an authorized signer, with signatures ordered in ascending public-key order.
+    ///
+    /// # Arguments
+    /// * `signature_payload` — A 32-byte hash of the transaction to authorize.
+    /// * `signatures` — A vector of ed25519 signatures, each with a public key and signature bytes, ordered by ascending public key.
+    /// * `_auth_contexts` — Intentionally unused; see [ADR-0007](../adr/0007-unscoped-multisig-authorization.md) for why this account does not scope authorization to specific contracts or functions during pre-alpha.
     fn __check_auth(
         env: Env,
         signature_payload: Hash<32>,
diff --git a/contracts/multisig-account/src/test.rs b/contracts/multisig-account/src/test.rs
index 638e820..e4a26ee 100644
--- a/contracts/multisig-account/src/test.rs
+++ b/contracts/multisig-account/src/test.rs
@@ -179,3 +179,22 @@ fn too_many_signatures_is_rejected() {
         Err(Ok(Error::TooManySigners))
     );
 }
+
+#[test]
+fn three_of_five_signers_authorize() {
+    let env = Env::default();
+    let mut keys = std::vec![
+        SigningKey::from_bytes(&[1; 32]),
+        SigningKey::from_bytes(&[2; 32]),
+        SigningKey::from_bytes(&[3; 32]),
+        SigningKey::from_bytes(&[4; 32]),
+        SigningKey::from_bytes(&[5; 32]),
+    ];
+    keys.sort_by_key(|key| key.verifying_key().to_bytes());
+    let account = register_account(&env, &keys, 3);
+    let payload = BytesN::from_array(&env, &[7; 32]);
+    // Supply exactly 3 signatures from the 5 signers in correct order
+    let signatures = signatures_for(&env, &keys[..3], &payload.to_array());
+
+    assert_eq!(check_auth(&env, &account, &payload, signatures), Ok(()));
+}