crossagent 0.1.0

Get a second opinion from another AI coding agent. Ask Claude, Codex, OpenCode, CommandCode, or Gemini — from inside the agent you already use.

crossagent

Get a second opinion from another AI agent — without leaving the one you're in.

crossagent lets your coding agent (Claude Code, Codex, Cursor, Cline, OpenCode, CommandCode…) pause and ask a different agent to independently evaluate a hard call — an architecture decision, a gnarly bug, a prompt rewrite — then hands you both viewpoints so you decide. One agent proposes; another one challenges. You get the disagreement, not just an echo.

crossagent --agent claude --name payments-retry-design --prompt-file /tmp/decision.md

• 🤝 Cross-agent, by design. Ask Claude, Codex, OpenCode, CommandCode, or Gemini — from inside whichever agent you already use.
• 🧠 A teammate, not an oracle. Ships a second-opinion protocol that forces an evidence-backed critique with cited files, risks, and a recommendation — then a synthesis step, so the second opinion sharpens your judgment instead of replacing it.
• 🔁 Named, resumable Claude sessions. Reuse a name to continue the same decision; fork to explore a branch. No re-explaining context every turn.
• 📡 Long-running & streamed. No default timeout, no default cost cap. It waits until the advisor finishes and streams progress as it goes.
• 🧩 Agent Skill + CLI. Installs as an Agent Skill and a standalone crossagent command. Zero runtime dependencies.
• 🔓 Local & open. Runs entirely on your machine against CLIs you already have. MIT licensed.

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Why

Coding agents are confident. That's the problem. The same model that writes the code also reviews it, so a plausible-but-wrong call sails straight through. The fix engineers already use with each other — "let me get a second pair of eyes" — works for agents too, but only if the second agent is actually different and is briefed well enough to disagree on the merits.

crossagent makes that a one-liner. Package the decision, hand it to a peer agent, get back a structured critique — Position / Evidence / Risks / Recommendation / Unresolved — and reconcile it with your own view before you commit.

Install

Install the CLI from PyPI (using pipx keeps command-line applications isolated):

pipx install crossagent
# or: pip install crossagent

crossagent --list-advisors

You also need at least one advisor CLI on your PATH — e.g. claude, codex, opencode, commandcode, or gemini.

To install both the CLI and the Agent Skill from the repository:

git clone https://github.com/datj9/crossagent.git
cd crossagent
./install.sh

The installer checks the supported agent config dirs (~/.claude, ~/.codex, ~/.config/opencode, ~/.commandcode, ~/.cursor), installs the skill into those present, and installs the CLI via pipx/pip.

Quick start

Write a compact decision brief, then ask a peer:

cat > /tmp/decision.md <<'EOF'
<decision>Should the payment retry live in the worker or the API layer?</decision>
<current_state>Retries currently inline in the API handler; p99 latency regressed 40%.</current_state>
<constraints>No new infra this quarter. Must stay idempotent.</constraints>
<evidence>src/api/payments.ts:88, worker/queue.ts:12, load test in bench/2026-07.md</evidence>
<questions>1. Which layer, and why? 2. Strongest counterargument? 3. Cheapest validation?</questions>
EOF

crossagent --agent claude --name payments-retry-design --cwd "$PWD" --prompt-file /tmp/decision.md

The advisor's answer prints to stdout; progress and session metadata go to stderr. Continue the same decision later — context is remembered:

crossagent --name payments-retry-design --prompt-file /tmp/followup.md   # auto-resumes
crossagent --name payments-retry-design --fork-session --prompt-file /tmp/alt.md  # branch it

Or let your agent do it for you — just say "ask Claude about this" / "hỏi ý với Claude" / "get a second opinion from Codex" and the skill fires.

How it works

your agent ──▶ crossagent CLI ──▶ peer agent's CLI (claude -p / codex exec / …)
     ▲              │                     │
     └── synthesis ─┴──── streamed ◀──────┘
         (you reconcile both views)       result + session id

1. You (or your agent) package the decision using the second-opinion protocol.
2. crossagent builds the right command for the chosen advisor and keeps it alive until it exits.
3. For session-capable advisors, it stores the session_id keyed by advisor:name so the next turn resumes.
4. You compare the two viewpoints and make the call.

Advisors

Advisor	Command	Status	Sessions
claude	claude -p	✅ full	resume, name, fork, streamed
codex	codex exec	🧪 experimental	text output
opencode	opencode run	🧪 experimental	text output
commandcode	commandcode -p	🧪 experimental	text output
gemini	gemini -p	🧪 experimental	text output

Experimental advisors ship best-effort default flags. If your install differs, fix them without touching code — see below.

Add or fix an advisor

Create ~/.config/crossagent/advisors.json:

{
  "advisors": {
    "codex": { "executable": "codex", "base_args": ["exec", "--full-auto"] },
    "myllm": { "executable": "myllm", "prompt_delivery": "flag:-q", "model_flag": "--model" }
  }
}

Fields layer onto the built-ins, so you only specify what differs. prompt_delivery is dashdash (prompt after --), positional (prompt as last arg), or flag:<flag> (prompt is the value of a flag).

Skill usage inside an agent

Once installed, the skill auto-triggers on phrases like "ask Claude", "debate with Claude", "ask Codex", "second opinion", "hỏi ý với Claude". The agent packages context, runs crossagent, and reports both views. See skills/crossagent/SKILL.md.

Examples

• Architecture decision
• Debugging second opinion

Security

• Secrets never belong in prompts, CLI args, logs, or copied context — the protocol says so and you should enforce it.
• Second-opinion sessions run read-only by convention; for Claude use --tools "" for pure reasoning or restrict with --allowedTools.
• Everything runs locally against CLIs you already trust. crossagent adds no network calls of its own.

Contributing

Issues and PRs welcome — especially hardening the experimental advisors against real installs. See CONTRIBUTING.md.

License

MIT © Dat Nguyen. See LICENSE.