feat: Add v0 detection, improve cursor detection

[cursor]

Summary

• Add upstream v0 detection via AI_AGENT=v0
• Align Cursor detection with upstream: CURSOR_TRACE_ID detects Cursor and CURSOR_AGENT detects cursor-cli
• Update tests, docs, changelog, version, and lock metadata

Verification

• python3 -m pytest
• python3 -m ruff check . && python3 -m ruff format --check .

  

[blainekasten]

@cursoragent can you do some web searching to see if these changes for the cursor agent detection are accurate? I think these changes are actually wrong based on my experience

[cursor]

Verdict: the Cursor detection change is accurate. No functional revert needed.

What I found:

• Upstream @vercel/detect-agent maps:
  • CURSOR_TRACE_ID -> cursor
  • CURSOR_AGENT or CURSOR_EXTENSION_HOST_ROLE=agent-exec -> cursor-cli
• Public Cursor Agent troubleshooting references use CURSOR_TRACE_ID to detect Cursor Agent terminal sessions.
• Current Cursor Agent CLI artifact sets CURSOR_AGENT=1 for commands it executes and does not reference CURSOR_TRACE_ID.
• The old CURSOR_INVOKED_AS == "agent" check looks weaker; Cursor CLI uses CURSOR_INVOKED_AS mainly to infer command name/binary, not as the runtime agent signal.

Action taken:

• Added a code comment clarifying the two signals.
• Clarified the changelog wording.
• Committed/pushed: 329cb19 Clarify Cursor agent detection signals

Verification:

• 48 passed
• ruff check . passed
• ruff format --check . passed

Env note: this cloud image lacked uv and python3.12-venv; I installed python3.12-venv to verify. For future agents, env setup prompt: “Install uv and Python venv support for this repo so uv sync --extra dev, pytest, and ruff work out of the box.”

Sources:

• https://raw.githubusercontent.com/vercel/vercel/main/packages/detect-agent/src/index.ts
• vercel/vercel@5e02289
• https://forum.cursor.com/t/how-to-fix-cursor-agent-not-using-default-zsh-shell-on-macos/37734