feat: Add v0 detection, improve cursor detection

.github/workflows/ci.yml

@@ -0,0 +1,35 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+jobs:
+  lint:
+    name: lint
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@d4b2f3b6ecc6e67c4457f6d3e41ec42d3d0fcb86 # v5.4.2
+        with:
+          version: "0.10.2"
+
+      - name: Install dependencies
+        run: uv sync --extra dev
+
+      - name: Check formatting
+        run: uv run ruff format --check .
+
+      - name: Lint
+        run: uv run ruff check .
+
+      - name: Type check
+        run: uv run mypy detect_agent
+
+      - name: Run tests
+        run: uv run pytest

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.2.1
+
+- Add support for v0 via `AI_AGENT=v0`
+- Sync Cursor detection with upstream: `CURSOR_TRACE_ID` detects Cursor IDE agent-terminal sessions, and `CURSOR_AGENT` detects cursor-cli commands
+
 ## 0.2.0
 
 - Improve detection for cursor agents

README.md

@@ -34,6 +34,7 @@ This package can detect the following AI agents and development environments:
 - **Antigravity** (Google DeepMind)
 - **GitHub Copilot** (via `AI_AGENT=github-copilot|github-copilot-cli`, `COPILOT_MODEL`, `COPILOT_ALLOW_ALL`, or `COPILOT_GITHUB_TOKEN`)
 - **Replit** (online IDE)
+- **v0** (Vercel's AI assistant, via `AI_AGENT=v0`)
 
 ## The AI_AGENT Standard
 

detect_agent/__init__.py

@@ -17,6 +17,7 @@
 OPENCODE: Literal["opencode"] = "opencode"
 GITHUB_COPILOT: Literal["github-copilot"] = "github-copilot"
 GITHUB_COPILOT_CLI: Literal["github-copilot-cli"] = "github-copilot-cli"
+V0: Literal["v0"] = "v0"
 PI: Literal["pi"] = "pi"
 
 KnownAgentNames = Literal[
@@ -32,6 +33,7 @@
     "augment-cli",
     "opencode",
     "github-copilot",
+    "v0",
     "pi",
 ]
 
@@ -66,6 +68,7 @@ class AgentResultNone(TypedDict):
     "AUGMENT_CLI": AUGMENT_CLI,
     "OPENCODE": OPENCODE,
     "GITHUB_COPILOT": GITHUB_COPILOT,
+    "V0": V0,
 }
 
 
@@ -76,16 +79,20 @@ def determine_agent() -> AgentResult:
         if name:
             if name in (GITHUB_COPILOT, GITHUB_COPILOT_CLI):
                 return {"is_agent": True, "agent": {"name": GITHUB_COPILOT}}
-            return {"is_agent": True, "agent": {"name": name}}  # type: ignore[return-value]
+            if name == V0:
+                return {"is_agent": True, "agent": {"name": V0}}
+            return {"is_agent": True, "agent": {"name": name}}  # type: ignore[return-value, misc]
 
     if os.environ.get("PI_CODING_AGENT"):
         return {"is_agent": True, "agent": {"name": PI}}
 
-    if os.environ.get("CURSOR_AGENT"):
+    # Cursor IDE agent-terminal sessions expose CURSOR_TRACE_ID; the
+    # cursor-agent CLI sets CURSOR_AGENT for commands it executes.
+    if os.environ.get("CURSOR_TRACE_ID"):
         return {"is_agent": True, "agent": {"name": CURSOR}}
 
     if (
-        os.environ.get("CURSOR_INVOKED_AS") == "agent"
+        os.environ.get("CURSOR_AGENT")
         or os.environ.get("CURSOR_EXTENSION_HOST_ROLE") == "agent-exec"
     ):
         return {"is_agent": True, "agent": {"name": CURSOR_CLI}}

pyproject.toml

@@ -7,15 +7,15 @@ packages = ["detect_agent"]
 
 [project]
 name = "detect_agent"
-version = "0.2.0"
+version = "0.2.1"
 description = "Detect if code is running in an AI agent or automated development environment"
 readme = "README.md"
 requires-python = ">=3.9"
 dependencies = []
 packages = ["detect_agent"]
 
 [project.optional-dependencies]
-dev = ["pytest>=7.0", "ruff>=0.8.0"]
+dev = ["mypy>=1.0", "pytest>=7.0", "ruff>=0.8.0"]
 
 [project.urls]
 Homepage = "https://github.com/togethercomputer/detect_agent"
@@ -39,3 +39,8 @@ ignore = []
 
 [tool.ruff.lint.per-file-ignores]
 "tests/**/*.py" = ["S101"]  # allow assert in tests
+
+[tool.mypy]
+python_version = "3.9"
+strict = true
+packages = ["detect_agent"]

tests/test_detect_agent.py

@@ -15,6 +15,7 @@
 _AGENT_ENV_VARS = (
     "AI_AGENT",
     "PI_CODING_AGENT",
+    "CURSOR_TRACE_ID",
     "CURSOR_AGENT",
     "CURSOR_EXTENSION_HOST_ROLE",
     "GEMINI_CLI",
@@ -90,11 +91,20 @@ def test_from_copilot_github_token(self, monkeypatch):
         assert result == {"is_agent": True, "agent": {"name": KNOWN_AGENTS["GITHUB_COPILOT"]}}
 
 
+class TestV0Detection:
+    """v0 detection."""
+
+    def test_from_ai_agent_v0(self, monkeypatch):
+        monkeypatch.setenv("AI_AGENT", "v0")
+        result = determine_agent()
+        assert result == {"is_agent": True, "agent": {"name": KNOWN_AGENTS["V0"]}}
+
+
 class TestCursorDetection:
     """Cursor detection."""
 
-    def test_cursor_agent_set_detects_cursor(self, monkeypatch):
-        monkeypatch.setenv("CURSOR_AGENT", "1")
+    def test_cursor_trace_id_set_detects_cursor(self, monkeypatch):
+        monkeypatch.setenv("CURSOR_TRACE_ID", "some-uuid")
         result = determine_agent()
         assert result == {"is_agent": True, "agent": {"name": KNOWN_AGENTS["CURSOR"]}}
 
@@ -109,7 +119,7 @@ def test_cursor_agent_not_set_returns_no_agent(self):
     def test_cursor_agent_set_detects_cursor_cli(self, monkeypatch):
         monkeypatch.setenv("CURSOR_AGENT", "1")
         result = determine_agent()
-        assert result == {"is_agent": True, "agent": {"name": KNOWN_AGENTS["CURSOR"]}}
+        assert result == {"is_agent": True, "agent": {"name": KNOWN_AGENTS["CURSOR_CLI"]}}
 
     def test_cursor_extension_host_role_agent_exec_detects_cursor_cli(self, monkeypatch):
         monkeypatch.setenv("CURSOR_EXTENSION_HOST_ROLE", "agent-exec")
@@ -275,6 +285,8 @@ class TestPriorityOrderDetection:
 
     def test_ai_agent_takes_highest_priority(self, monkeypatch):
         monkeypatch.setenv("AI_AGENT", "custom-priority")
+        monkeypatch.setenv("PI_CODING_AGENT", "1")
+        monkeypatch.setenv("CURSOR_TRACE_ID", "some-uuid")
         monkeypatch.setenv("CURSOR_AGENT", "1")
         monkeypatch.setenv("GEMINI_CLI", "1")
         monkeypatch.setenv("CODEX_SANDBOX", "seatbelt")
@@ -291,7 +303,8 @@ def test_ai_agent_takes_highest_priority(self, monkeypatch):
             result = determine_agent()
         assert result == {"is_agent": True, "agent": {"name": "custom-priority"}}
 
-    def test_cursor_agent_takes_priority_over_remaining_agents(self, monkeypatch):
+    def test_cursor_trace_id_takes_priority_over_remaining_agents(self, monkeypatch):
+        monkeypatch.setenv("CURSOR_TRACE_ID", "some-uuid")
         monkeypatch.setenv("CURSOR_AGENT", "1")
         monkeypatch.setenv("GEMINI_CLI", "1")
         monkeypatch.setenv("CODEX_SANDBOX", "seatbelt")
@@ -308,12 +321,30 @@ def test_cursor_agent_takes_priority_over_remaining_agents(self, monkeypatch):
             result = determine_agent()
         assert result == {"is_agent": True, "agent": {"name": KNOWN_AGENTS["CURSOR"]}}
 
+    def test_cursor_agent_takes_priority_over_remaining_agents(self, monkeypatch):
+        monkeypatch.setenv("CURSOR_AGENT", "1")
+        monkeypatch.setenv("GEMINI_CLI", "1")
+        monkeypatch.setenv("CODEX_SANDBOX", "seatbelt")
+        monkeypatch.setenv("ANTIGRAVITY_AGENT", "1")
+        monkeypatch.setenv("AUGMENT_AGENT", "1")
+        monkeypatch.setenv("OPENCODE_CLIENT", "opencode")
+        monkeypatch.setenv("CLAUDE_CODE", "1")
+        monkeypatch.setenv("REPL_ID", "1")
+        monkeypatch.setenv("COPILOT_MODEL", "gpt-5")
+        monkeypatch.setenv("COPILOT_ALLOW_ALL", "true")
+        monkeypatch.setenv("COPILOT_GITHUB_TOKEN", "ghp_xxx")
+        with patch.object(Path, "exists") as mock_exists:
+            mock_exists.side_effect = lambda self: str(self) == DEVIN_LOCAL_PATH
+            result = determine_agent()
+        assert result == {"is_agent": True, "agent": {"name": KNOWN_AGENTS["CURSOR_CLI"]}}
+
 
 class TestEdgeCases:
     """Edge cases."""
 
     def test_empty_string_env_vars(self, monkeypatch):
         monkeypatch.setenv("AI_AGENT", "")
+        monkeypatch.setenv("CURSOR_TRACE_ID", "")
         result = determine_agent()
         assert result == {"is_agent": False, "agent": None}
 
@@ -347,7 +378,7 @@ def test_is_agent_boolean(self, monkeypatch):
         assert result["is_agent"] is True
 
     def test_agent_details_when_detected(self, monkeypatch):
-        monkeypatch.setenv("CURSOR_AGENT", "1")
+        monkeypatch.setenv("CURSOR_TRACE_ID", "some-id")
         result = determine_agent()
         assert result["is_agent"] is True
         assert result.get("agent") is not None