diff --git a/CHANGELOG.md b/CHANGELOG.md
index 23a80751..b7d238de 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Ephemeral generated project context (#3058).** Opening CodeWhale in a
   directory with no instruction files now keeps the bounded generated project
   overview in memory instead of creating `.codewhale/instructions.md`.
+- **ACP registry auth metadata (#1447).** The ACP stdio adapter now advertises
+  terminal authentication setup in `initialize.authMethods`, matching the
+  registry's validation requirement.
 - **Cursor-style activity metadata rows (#3146).** Dense successful tool-run
   summaries now render as a single muted `Explored ...` / `Updated metadata`
   row, include short command-family labels for successful generic verifier
diff --git a/crates/tui/CHANGELOG.md b/crates/tui/CHANGELOG.md
index 1b47fea7..bf04d649 100644
--- a/crates/tui/CHANGELOG.md
+++ b/crates/tui/CHANGELOG.md
@@ -16,6 +16,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Ephemeral generated project context (#3058).** Opening CodeWhale in a
   directory with no instruction files now keeps the bounded generated project
   overview in memory instead of creating `.codewhale/instructions.md`.
+- **ACP registry auth metadata (#1447).** The ACP stdio adapter now advertises
+  terminal authentication setup in `initialize.authMethods`, matching the
+  registry's validation requirement.
 - **Cursor-style activity metadata rows (#3146).** Dense successful tool-run
   summaries now render as a single muted `Explored ...` / `Updated metadata`
   row, include short command-family labels for successful generic verifier
diff --git a/crates/tui/src/acp_server.rs b/crates/tui/src/acp_server.rs
index 72a110cf..6d28c66d 100644
--- a/crates/tui/src/acp_server.rs
+++ b/crates/tui/src/acp_server.rs
@@ -125,6 +125,7 @@ impl AcpServer {
         match method {
             "initialize" => Ok(AcpDispatch::Response(initialize_result(
                 params.get("protocolVersion").and_then(Value::as_u64),
+                &self.config,
             ))),
             "session/new" => Ok(AcpDispatch::Response(self.new_session(params)?)),
             "session/prompt" => {
@@ -265,7 +266,7 @@ impl AcpError {
     }
 }
 
-fn initialize_result(client_protocol_version: Option<u64>) -> Value {
+fn initialize_result(client_protocol_version: Option<u64>, config: &Config) -> Value {
     json!({
         "protocolVersion": client_protocol_version
             .map(|version| version.min(ACP_PROTOCOL_VERSION))
@@ -288,10 +289,24 @@ fn initialize_result(client_protocol_version: Option<u64>) -> Value {
             "title": "codewhale",
             "version": env!("CARGO_PKG_VERSION")
         },
-        "authMethods": []
+        "authMethods": acp_auth_methods(config)
     })
 }
 
+fn acp_auth_methods(config: &Config) -> Value {
+    let provider = config.api_provider().as_str();
+    json!([
+        {
+            "id": "codewhale-terminal-auth",
+            "name": "Set CodeWhale API key",
+            "description": format!("Run CodeWhale's terminal credential setup for the {provider} provider."),
+            "type": "terminal",
+            "args": ["auth", "set", "--provider", provider],
+            "env": {}
+        }
+    ])
+}
+
 fn extract_prompt_text(prompt: Option<&Value>) -> Option<String> {
     match prompt? {
         Value::String(text) => Some(text.clone()),
@@ -420,7 +435,7 @@ mod tests {
 
     #[test]
     fn initialize_advertises_baseline_acp_agent() {
-        let result = initialize_result(Some(1));
+        let result = initialize_result(Some(1), &Config::default());
 
         assert_eq!(result["protocolVersion"], 1);
         assert_eq!(result["agentInfo"]["name"], "codewhale");
@@ -429,7 +444,11 @@ mod tests {
             result["agentCapabilities"]["promptCapabilities"]["embeddedContext"],
             true
         );
-        assert_eq!(result["authMethods"], json!([]));
+        assert_eq!(result["authMethods"][0]["type"], "terminal");
+        assert_eq!(
+            result["authMethods"][0]["args"],
+            json!(["auth", "set", "--provider", "deepseek"])
+        );
     }
 
     #[test]