feat(desktop): add GitHub Copilot CLI harness

VISION.md

@@ -219,7 +219,7 @@ Greenfield. Agent swarms build in parallel, integrating at the event store bound
 |-|------|
 | ✅ | Core relay, auth, pub/sub, search, audit |
 | ✅ | MCP server — full feature surface |
-| ✅ | ACP agent harness — goose, codex, claude code |
+| ✅ | ACP agent harness — goose, codex, claude code, GitHub Copilot CLI |
 | ✅ | Desktop client (Tauri) — Stream, Home, Forum, DMs, Agents, Workflows, Search, Settings, Profiles, Presence |
 | ✅ | Channel features — messaging, threads, reactions, canvases, media uploads, editing, deletion, typing indicators, NIP-29, soft-delete |
 | ✅ | Workflow engine — YAML-as-code, execution traces, message/reaction/schedule/webhook triggers |

desktop/src-tauri/src/commands/agent_auth.rs

@@ -12,6 +12,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::managed_agents::{
     default_agent_workdir, known_acp_runtime_exact, normalize_agent_args, resolve_command,
+    AuthStatus,
 };
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
@@ -77,6 +78,46 @@ fn discover_acp_auth_methods_blocking(runtime_id: &str) -> Result<AcpAuthMethods
         .map_err(|error| format!("failed to parse auth methods JSON: {error}"))
 }
 
+/// Probe authentication by creating an ACP session and listing its models.
+///
+/// GitHub Copilot CLI has no non-interactive status command. Its ACP
+/// `session/new` path returns models only when the stored account is usable.
+/// Only forced catalog discovery runs this process; cheap discovery reuses the
+/// in-process auth cache until the next forced refresh. The probe sends no
+/// prompt.
+pub(crate) fn probe_acp_runtime_auth(runtime_id: &str) -> AuthStatus {
+    match run_buzz_acp_auth_command(runtime_id, ["models", "--json"]) {
+        Ok(output) if output.status.success() => AuthStatus::LoggedIn,
+        Ok(output) => {
+            let stderr = String::from_utf8_lossy(&output.stderr);
+            match crate::managed_agents::readiness::cli_probe::classify_probe_output(
+                stderr.as_bytes(),
+                false,
+            ) {
+                crate::managed_agents::readiness::cli_probe::ProbeOutcome::LoggedIn => {
+                    AuthStatus::LoggedIn
+                }
+                crate::managed_agents::readiness::cli_probe::ProbeOutcome::LoggedOut => {
+                    AuthStatus::LoggedOut
+                }
+                crate::managed_agents::readiness::cli_probe::ProbeOutcome::ConfigInvalid {
+                    stderr_excerpt,
+                } => AuthStatus::ConfigInvalid {
+                    diagnostic: stderr_excerpt,
+                },
+            }
+        }
+        Err(error) => {
+            tracing::debug!(
+                runtime_id,
+                error = %error,
+                "ACP runtime auth probe could not start"
+            );
+            AuthStatus::Unknown
+        }
+    }
+}
+
 fn connect_acp_runtime_blocking(
     request: &ConnectAcpRuntimeRequest,
 ) -> Result<ConnectAcpRuntimeResult, String> {

desktop/src-tauri/src/managed_agents/discovery.rs

@@ -31,6 +31,7 @@ pub(crate) use runtime_metadata::KnownAcpRuntime;
 const GOOSE_AVATAR_URL: &str = "https://goose-docs.ai/img/logo_dark.png";
 const CLAUDE_CODE_AVATAR_URL: &str = "https://anthropic.gallerycdn.vsassets.io/extensions/anthropic/claude-code/2.1.77/1773707456892/Microsoft.VisualStudio.Services.Icons.Default";
 const CODEX_AVATAR_URL: &str = "https://openai.gallerycdn.vsassets.io/extensions/openai/chatgpt/26.5313.41514/1773706730621/Microsoft.VisualStudio.Services.Icons.Default";
+const COPILOT_CLI_AVATAR_URL: &str = "https://avatars.githubusercontent.com/u/9919?s=200&v=4";
 const BUZZ_AGENT_AVATAR_URL: &str =
     "https://raw.githubusercontent.com/block/buzz/refs/heads/main/crates/buzz-agent/buzz-agent.png";
 fn common_binary_paths() -> &'static [PathBuf] {
@@ -186,6 +187,39 @@ const KNOWN_ACP_RUNTIMES: &[KnownAcpRuntime] = &[
         // Verified: `codex login status` exits 0 when logged in, non-zero otherwise.
         auth_probe_args: Some(&["codex", "login", "status"]),
     },
+    KnownAcpRuntime {
+        id: "copilot",
+        label: "GitHub Copilot CLI",
+        commands: &["copilot"],
+        aliases: &["github-copilot", "gh-copilot"],
+        avatar_url: COPILOT_CLI_AVATAR_URL,
+        mcp_command: None,
+        mcp_hooks: false,
+        underlying_cli: Some("copilot"),
+        cli_install_commands: &[],
+        cli_install_commands_windows: &[],
+        adapter_install_commands: &[],
+        cli_install_instructions_url: "https://docs.github.com/en/copilot/how-tos/set-up/install-copilot-cli",
+        adapter_install_instructions_url: "",
+        cli_install_hint: "Install GitHub Copilot CLI, then sign in with your GitHub account. Buzz uses its built-in ACP server directly.",
+        adapter_install_hint: "",
+        skill_dir: None,
+        supports_acp_model_switching: true,
+        model_env_var: None,
+        provider_env_var: None,
+        provider_locked: false,
+        default_env: &[],
+        config_file_path: Some("~/.copilot/config.json"),
+        config_file_format: Some("json"),
+        supports_acp_native_config: false,
+        thinking_env_var: None,
+        max_tokens_env_var: None,
+        context_limit_env_var: None,
+        max_rounds_env_var: None,
+        required_normalized_fields: &[],
+        login_hint: Some("Run `copilot login` to authenticate."),
+        auth_probe_args: None,
+    },
     KnownAcpRuntime {
         id: "buzz-agent",
         label: "Buzz Agent",
@@ -451,19 +485,30 @@ pub fn try_record_agent_command(
 fn default_agent_args(command: &str) -> Option<Vec<String>> {
     match normalize_command_identity(command).as_str() {
         "goose" => Some(vec!["acp".to_string()]),
+        "copilot" | "github-copilot" | "gh-copilot" => Some(vec!["--acp".to_string()]),
         "codex" | "codex-acp" | "claude-agent-acp" | "claude-code-acp" | "claude-code"
         | "claudecode" | "buzz-agent" => Some(Vec::new()),
         _ => None,
     }
 }
 
 pub fn normalize_agent_args(command: &str, agent_args: Vec<String>) -> Vec<String> {
-    let normalized = agent_args
+    let mut normalized = agent_args
         .into_iter()
         .map(|arg| arg.trim().to_string())
         .filter(|arg| !arg.is_empty())
         .collect::<Vec<_>>();
 
+    if matches!(
+        normalize_command_identity(command).as_str(),
+        "copilot" | "github-copilot" | "gh-copilot"
+    ) {
+        if !normalized.iter().any(|arg| arg == "--acp") {
+            normalized.insert(0, "--acp".to_string());
+        }
+        return normalized;
+    }
+
     let Some(default_args) = default_agent_args(command) else {
         return normalized;
     };
@@ -1297,7 +1342,7 @@ pub fn discover_acp_runtimes_from(
         if partial.entry.auth_status == AuthStatus::Unknown {
             partial.entry.auth_status = if partial.entry.availability
                 == AcpAvailabilityStatus::Available
-                && partial.runtime.auth_probe_args.is_none()
+                && !auth_status_cache::runtime_is_probeable(partial.runtime)
             {
                 AuthStatus::NotApplicable
             } else {

desktop/src-tauri/src/managed_agents/discovery/auth_status_cache.rs

@@ -39,6 +39,10 @@ pub(super) fn get(runtime_id: &str) -> AuthStatus {
         .unwrap_or(AuthStatus::Unknown)
 }
 
+pub(super) fn runtime_is_probeable(runtime: &super::KnownAcpRuntime) -> bool {
+    runtime.id == "copilot" || runtime.auth_probe_args.is_some()
+}
+
 #[cfg(test)]
 pub(crate) fn len() -> usize {
     cache().lock().map(|g| g.len()).unwrap_or(0)
@@ -62,6 +66,11 @@ pub(super) fn resolve_auth_statuses(partials: &mut [super::PartialEntry], force:
                 if partial.entry.availability != AcpAvailabilityStatus::Available {
                     return None;
                 }
+                if partial.runtime.id == "copilot" {
+                    let handle =
+                        std::thread::spawn(|| crate::commands::probe_acp_runtime_auth("copilot"));
+                    return Some((idx, handle));
+                }
                 let probe_args = partial.runtime.auth_probe_args?;
                 // Need the resolved binary path for the CLI (e.g. the actual `claude` binary).
                 let binary_path = super::resolve_command(probe_args[0])?;
@@ -84,7 +93,7 @@ pub(super) fn resolve_auth_statuses(partials: &mut [super::PartialEntry], force:
     } else {
         for partial in partials.iter_mut() {
             if partial.entry.availability != AcpAvailabilityStatus::Available
-                || partial.runtime.auth_probe_args.is_none()
+                || !runtime_is_probeable(partial.runtime)
             {
                 continue;
             }

desktop/src-tauri/src/managed_agents/discovery/runtime_metadata.rs

@@ -85,7 +85,7 @@ impl KnownAcpRuntime {
 
 #[cfg(test)]
 mod tests {
-    use super::super::known_acp_runtime_exact;
+    use super::super::{auth_status_cache, known_acp_runtime_exact};
 
     #[test]
     fn vendor_metadata_distinguishes_cli_and_adapter_guidance() {
@@ -122,5 +122,19 @@ mod tests {
         );
         assert!(codex.adapter_install_instructions_url.contains("codex-acp"));
         assert!(codex.cli_install_hint.contains("Codex CLI"));
+
+        let copilot = known_acp_runtime_exact("copilot").unwrap();
+        assert_eq!(copilot.commands, &["copilot"]);
+        assert_eq!(
+            copilot.avatar_url,
+            "https://avatars.githubusercontent.com/u/9919?s=200&v=4"
+        );
+        assert!(copilot.adapter_install_commands.is_empty());
+        assert!(copilot.cli_install_hint.contains("built-in ACP server"));
+        assert!(copilot
+            .cli_install_instructions_url
+            .contains("docs.github.com"));
+        assert!(copilot.supports_acp_model_switching);
+        assert!(auth_status_cache::runtime_is_probeable(copilot));
     }
 }

desktop/src-tauri/src/managed_agents/discovery/tests.rs

@@ -7,7 +7,8 @@ use super::{
     effective_agent_command, find_nvm_default_bin, is_login_shell_path_uninit, is_safe_nvm_tag,
     managed_agent_avatar_url, normalize_agent_args, parse_semver_tag, probe_codex_acp_version,
     record_agent_command, refresh_login_shell_path, try_record_agent_command,
-    BUZZ_AGENT_AVATAR_URL, CLAUDE_CODE_AVATAR_URL, CODEX_AVATAR_URL, GOOSE_AVATAR_URL,
+    BUZZ_AGENT_AVATAR_URL, CLAUDE_CODE_AVATAR_URL, CODEX_AVATAR_URL, COPILOT_CLI_AVATAR_URL,
+    GOOSE_AVATAR_URL,
 };
 use crate::managed_agents::AcpAvailabilityStatus;
 
@@ -69,6 +70,51 @@ fn normalizes_claude_and_codex_args_to_empty() {
     );
 }
 
+#[test]
+fn normalizes_copilot_args_to_native_stdio_acp_mode() {
+    let expected = vec!["--acp".to_string()];
+    assert_eq!(normalize_agent_args("copilot", Vec::new()), expected);
+    assert_eq!(
+        normalize_agent_args(r"C:\Tools\copilot.exe", Vec::new()),
+        vec!["--acp".to_string()]
+    );
+    assert_eq!(
+        normalize_agent_args("gh-copilot", Vec::new()),
+        vec!["--acp".to_string()]
+    );
+    assert_eq!(
+        normalize_agent_args("copilot", vec!["--allow-all-tools".to_string()]),
+        vec!["--acp".to_string(), "--allow-all-tools".to_string()]
+    );
+    assert_eq!(
+        normalize_agent_args(
+            "copilot",
+            vec![
+                "--acp".to_string(),
+                "--model".to_string(),
+                "gpt-5.4".to_string()
+            ]
+        ),
+        vec![
+            "--acp".to_string(),
+            "--model".to_string(),
+            "gpt-5.4".to_string()
+        ]
+    );
+}
+
+#[test]
+fn resolves_copilot_avatar_for_command_and_alias() {
+    assert_eq!(
+        managed_agent_avatar_url("copilot"),
+        Some(COPILOT_CLI_AVATAR_URL.to_string())
+    );
+    assert_eq!(
+        managed_agent_avatar_url("GitHub Copilot"),
+        Some(COPILOT_CLI_AVATAR_URL.to_string())
+    );
+}
+
 #[test]
 fn resolves_buzz_agent_avatar() {
     assert_eq!(

desktop/src/features/agents/AGENTS.md

@@ -301,3 +301,7 @@ matches the code is worse than no rule; a new pattern that isn't written down
 here will be broken by the next agent that never learns it existed. Reviewers:
 treat a config-behavior diff without a matching AGENTS.md diff (or an explicit
 "no rules changed" note) as incomplete.
+
+GitHub Copilot CLI follows the existing catalog-owned capability model. Its
+provider submission classification only extends the pre-catalog fallback for
+CLI-login runtimes; no configuration rule changes.

desktop/src/features/agents/ui/personaRuntimeModel.test.mjs

@@ -195,6 +195,7 @@ test("resolveRuntimeProviderCapability classifies known CLI-login runtimes as lo
   // The core fix: a not-yet-loaded catalog must not force these to "unknown".
   assert.equal(resolveRuntimeProviderCapability("claude", false), "locked");
   assert.equal(resolveRuntimeProviderCapability("codex", false), "locked");
+  assert.equal(resolveRuntimeProviderCapability("copilot", false), "locked");
   assert.equal(resolveRuntimeProviderCapability(" claude ", false), "locked");
 });
 

desktop/src/features/agents/ui/personaRuntimeModel.ts

@@ -18,7 +18,7 @@ export type ProviderRuntimeCapability = "capable" | "locked" | "unknown";
  * provider. To avoid that, we resolve capability STATICALLY for known ids:
  *
  * - buzz-agent / goose → "capable" (`isProviderCapable`, id-based).
- * - claude / codex → "locked" (CLI-login runtimes; no LLM provider selection).
+ * - claude / codex / copilot → "locked" (CLI-login runtimes; no LLM provider selection).
  * - anything else (custom, empty, genuinely unknown) → "unknown".
  *
  * `isProviderCapable` is the caller-supplied {@link
@@ -33,7 +33,7 @@ export function resolveRuntimeProviderCapability(
     return "capable";
   }
   const id = runtimeId.trim();
-  if (id === "claude" || id === "codex") {
+  if (id === "claude" || id === "codex" || id === "copilot") {
     return "locked";
   }
   return "unknown";

desktop/src/testing/e2eBridge.ts

@@ -8148,6 +8148,27 @@ async function handleDiscoverAcpRuntimes(
       source: "builtin",
       login_hint: undefined,
     },
+    {
+      id: "copilot",
+      label: "GitHub Copilot CLI",
+      avatar_url: "",
+      availability: "available",
+      command: "copilot",
+      binary_path: "/usr/local/bin/copilot",
+      default_args: ["--acp"],
+      mcp_command: null,
+      install_hint:
+        "Install GitHub Copilot CLI, then sign in with your GitHub account. Buzz uses its built-in ACP server directly.",
+      install_instructions_url:
+        "https://docs.github.com/en/copilot/how-tos/set-up/install-copilot-cli",
+      can_auto_install: false,
+      requires_external_cli: true,
+      underlying_cli_path: "/usr/local/bin/copilot",
+      node_required: false,
+      auth_status: { status: "logged_in" },
+      source: "builtin",
+      login_hint: undefined,
+    },
     {
       id: "buzz-agent",
       label: "Buzz Agent",
@@ -8163,7 +8184,7 @@ async function handleDiscoverAcpRuntimes(
       requires_external_cli: false,
       underlying_cli_path: null,
       node_required: false,
-      auth_status: { status: "not_applicable" },
+      auth_status: { status: "logged_in" },
       source: "builtin",
       login_hint: undefined,
     },

desktop/tests/e2e/harness-catalog-screenshots.spec.ts

@@ -25,7 +25,7 @@ const CATALOG = [
     can_auto_install: false,
     underlying_cli_path: null,
     node_required: false,
-    auth_status: { status: "not_applicable" },
+    auth_status: { status: "logged_in" },
   },
   {
     id: "claude",
@@ -79,6 +79,26 @@ const CATALOG = [
     auth_status: { status: "not_applicable" },
     source: "preset",
   },
+  {
+    id: "copilot",
+    label: "GitHub Copilot CLI",
+    avatar_url: "",
+    availability: "available",
+    command: "copilot",
+    binary_path: "/usr/local/bin/copilot",
+    default_args: ["--acp"],
+    mcp_command: null,
+    install_hint:
+      "Buzz uses GitHub Copilot CLI's built-in ACP server directly.",
+    install_instructions_url:
+      "https://docs.github.com/en/copilot/how-tos/set-up/install-copilot-cli",
+    can_auto_install: false,
+    requires_external_cli: true,
+    underlying_cli_path: "/usr/local/bin/copilot",
+    node_required: false,
+    auth_status: { status: "logged_in" },
+    source: "builtin",
+  },
   {
     id: "omp",
     label: "Oh My Pi",
@@ -163,7 +183,7 @@ test("after: consolidated harnesses panel + catalog dialog", async ({
   // 3. Ready entry detail (Ready state, no install action). Ready entries
   // sit in the "Installed" accordion, collapsed by default — expand it.
   await page.getByTestId("harness-catalog-section-installed").click();
-  await page.getByTestId("harness-catalog-list-item-claude").click();
+  await page.getByTestId("harness-catalog-list-item-copilot").click();
   await page.waitForTimeout(300);
   await page.getByTestId("harness-catalog-dialog").screenshot({
     path: `${SHOTS}/after-catalog-ready-detail.png`,