feat(acp): enforce deterministic agent git commit identity

Cargo.toml

@@ -24,6 +24,7 @@ members = [
     "crates/buzz-persona",
     "crates/git-credential-nostr",
     "crates/git-sign-nostr",
+    "crates/buzz-git-identity",
     "crates/buzz-pair-relay",
     "crates/buzz-relay-mesh",
     "crates/buzz-dev-mcp",

crates/buzz-acp/Cargo.toml

@@ -53,6 +53,10 @@ url = { workspace = true }
 sha2 = { workspace = true }
 base64 = "0.22"
 hex = { workspace = true }
+buzz-git-identity = { path = "../buzz-git-identity" }
+git-credential-nostr = { path = "../git-credential-nostr" }
+git-sign-nostr = { path = "../git-sign-nostr" }
+tempfile = "3"
 
 # Logging
 tracing = { workspace = true }

crates/buzz-acp/src/base_prompt.md

@@ -144,7 +144,7 @@ These are guidelines, not a fixed procedure — apply judgment to the task in fr
 - After selecting a repository or worktree, read its root `AGENTS.md` and any path-local `AGENTS.md` files that apply before planning or editing. The workspace-level file is team context; it does not replace repository-owned instructions.
 - Treat repository-owned product, architecture, and vision documents as design constraints, not optional background. Read the relevant documents before making non-trivial plans, and surface any intentional conflict with them.
 - Make file changes in a worktree, not on the default branch. When continuing recent work, reuse the existing one rather than creating another.
-- Before committing, read the repo-local git `user.name` / `user.email`; if email is empty, stop and ask. Include the trailers the repo requires.
+- Your commit author identity is machine-managed: every commit is automatically authored and signed as your agent identity (`<pubkey>@<relay-host>`). Never set `user.name`/`user.email`, and never pass `-c user.*`, `--author`, or `--reset-author` — the managed `git` rejects those. Credit the human operator with the `Co-authored-by` and `Signed-off-by` trailers the repo requires (add them to the commit message body); if you cannot determine the operator's email for those trailers, stop and ask. (When the operator sets `BUZZ_GIT_IDENTITY=user`, commits instead carry their own git identity and these trailers are redundant.)
 
 ## Autonomy
 

crates/buzz-acp/src/lib.rs

@@ -1895,10 +1895,47 @@ mod idle_pool_sleep_tests {
 }
 
 pub fn run() -> Result<()> {
+    // Multicall git-helper personalities — when the harness binary is invoked
+    // under one of these names (via the symlinks it installs on the
+    // agent-runtime child's PATH; see `AcpClient::install_git_identity`), it
+    // dispatches to that personality and exits before any harness setup. This
+    // makes buzz-acp self-contained for deterministic agent git identity: the
+    // enforcement wrapper AND the nostr signer/credential helper it configures
+    // are all reachable from a single binary, with no dependency on a separately
+    // resolvable buzz-dev-mcp. Mirrors buzz-dev-mcp's own shim dispatch so the
+    // native shells of every runtime hit the same identity-enforcing git.
+    match git_multicall_personality() {
+        Some(GitPersonality::Git) => std::process::exit(buzz_git_identity::git_wrapper::run()),
+        Some(GitPersonality::SignNostr) => std::process::exit(git_sign_nostr::run()),
+        Some(GitPersonality::CredentialNostr) => std::process::exit(git_credential_nostr::run()),
+        None => {}
+    }
     config::propagate_legacy_env_vars();
     tokio_main()
 }
 
+/// A git-helper multicall personality this binary can assume based on argv[0].
+enum GitPersonality {
+    Git,
+    SignNostr,
+    CredentialNostr,
+}
+
+/// The multicall personality implied by argv[0]'s file stem, or `None` when the
+/// binary was launched normally as `buzz-acp`.
+fn git_multicall_personality() -> Option<GitPersonality> {
+    let stem = std::env::args_os()
+        .next()
+        .map(std::path::PathBuf::from)
+        .and_then(|p| p.file_stem().map(|s| s.to_ascii_lowercase()))?;
+    match stem.to_str()? {
+        "git" => Some(GitPersonality::Git),
+        "git-sign-nostr" => Some(GitPersonality::SignNostr),
+        "git-credential-nostr" => Some(GitPersonality::CredentialNostr),
+        _ => None,
+    }
+}
+
 #[tokio::main]
 async fn tokio_main() -> Result<()> {
     // Install the ring crypto provider for rustls (required for wss:// connections).
@@ -4826,6 +4863,18 @@ fn extract_auth_methods(init_result: &serde_json::Value) -> Vec<serde_json::Valu
         .unwrap_or_default()
 }
 
+/// Shut down the client and exit with `code` after printing `msg` to stderr.
+///
+/// `std::process::exit` runs no destructors, so error/timeout paths must call
+/// `shutdown().await` — which reaps the child AND deletes the git-identity
+/// keyfile tempdir — before exiting. Taking the client by value guarantees no
+/// caller can exit while still holding a live client (and thus a live keyfile).
+async fn shutdown_and_exit(mut client: AcpClient, msg: &str, code: i32) -> ! {
+    client.shutdown().await;
+    eprintln!("{msg}");
+    std::process::exit(code)
+}
+
 /// `buzz-acp auth-methods` — spawn an adapter, initialize it, print authMethods.
 async fn run_auth_methods(args: AuthMethodsArgs) -> Result<()> {
     let mut client = match spawn_auth_client(&args.agent).await {
@@ -4839,14 +4888,15 @@ async fn run_auth_methods(args: AuthMethodsArgs) -> Result<()> {
     let init_result = match tokio::time::timeout(MODELS_TIMEOUT, client.initialize()).await {
         Ok(Ok(result)) => result,
         Ok(Err(e)) => {
-            client.shutdown().await;
-            eprintln!("error: agent initialize failed: {e}");
-            std::process::exit(1);
+            shutdown_and_exit(client, &format!("error: agent initialize failed: {e}"), 1).await;
         }
         Err(_) => {
-            client.shutdown().await;
-            eprintln!("error: agent timed out ({MODELS_TIMEOUT:?})");
-            std::process::exit(1);
+            shutdown_and_exit(
+                client,
+                &format!("error: agent timed out ({MODELS_TIMEOUT:?})"),
+                1,
+            )
+            .await;
         }
     };
 
@@ -4887,27 +4937,31 @@ async fn run_authenticate(args: AuthenticateArgs) -> Result<()> {
     let init_result = match tokio::time::timeout(MODELS_TIMEOUT, client.initialize()).await {
         Ok(Ok(result)) => result,
         Ok(Err(e)) => {
-            client.shutdown().await;
-            eprintln!("error: agent initialize failed: {e}");
-            std::process::exit(1);
+            shutdown_and_exit(client, &format!("error: agent initialize failed: {e}"), 1).await;
         }
         Err(_) => {
-            client.shutdown().await;
-            eprintln!("error: agent initialize timed out ({MODELS_TIMEOUT:?})");
-            std::process::exit(1);
+            shutdown_and_exit(
+                client,
+                &format!("error: agent initialize timed out ({MODELS_TIMEOUT:?})"),
+                1,
+            )
+            .await;
         }
     };
 
     let supports_method = extract_auth_methods(&init_result)
         .iter()
         .any(|method| method.get("id").and_then(|id| id.as_str()) == Some(args.method_id.as_str()));
     if !supports_method {
-        client.shutdown().await;
-        eprintln!(
-            "error: auth method '{}' is not advertised by this adapter",
-            args.method_id
-        );
-        std::process::exit(1);
+        shutdown_and_exit(
+            client,
+            &format!(
+                "error: auth method '{}' is not advertised by this adapter",
+                args.method_id
+            ),
+            1,
+        )
+        .await;
     }
 
     let result =
@@ -4919,14 +4973,15 @@ async fn run_authenticate(args: AuthenticateArgs) -> Result<()> {
             Ok(())
         }
         Ok(Err(e)) => {
-            client.shutdown().await;
-            eprintln!("error: authenticate failed: {e}");
-            std::process::exit(1);
+            shutdown_and_exit(client, &format!("error: authenticate failed: {e}"), 1).await;
         }
         Err(_) => {
-            client.shutdown().await;
-            eprintln!("error: authenticate timed out ({AUTHENTICATE_TIMEOUT:?})");
-            std::process::exit(1);
+            shutdown_and_exit(
+                client,
+                &format!("error: authenticate timed out ({AUTHENTICATE_TIMEOUT:?})"),
+                1,
+            )
+            .await;
         }
     }
 }
@@ -4962,14 +5017,20 @@ async fn run_models(args: ModelsArgs) -> Result<()> {
     let (init_result, session_resp) = match protocol_result {
         Ok(Ok(tuple)) => tuple,
         Ok(Err(e)) => {
-            client.shutdown().await;
-            eprintln!("error: agent communication failed: {e}");
-            std::process::exit(1);
+            shutdown_and_exit(
+                client,
+                &format!("error: agent communication failed: {e}"),
+                1,
+            )
+            .await;
         }
         Err(_) => {
-            client.shutdown().await;
-            eprintln!("error: agent timed out ({MODELS_TIMEOUT:?})");
-            std::process::exit(1);
+            shutdown_and_exit(
+                client,
+                &format!("error: agent timed out ({MODELS_TIMEOUT:?})"),
+                1,
+            )
+            .await;
         }
     };