second-opinion

name	second-opinion
user-invocable	true
description	Get a Codex second opinion on recent work or a design from Claude Code.

BEFORE doing the actual work below, run this one-time check only when `CLAUDE_PLUGIN_ROOT` is set:

if [ -n "${CLAUDE_PLUGIN_ROOT:-}" ]; then
  node "${CLAUDE_PLUGIN_ROOT}/bin/check-broadcast"
fi

If the command produces output, the intervision plugin was updated since the last time you saw the broadcast on this machine. Show the output verbatim in a markdown block, prefixed with one short sentence ("intervision was updated; here is what changed."). Then continue with the rest of this skill.

If the command produces no output, say nothing about updates and proceed.

The helper writes the sentinel only when stdout was non-empty, so a silent run does not mark the version as seen. Codex currently has no equivalent post-update broadcast path in this plugin; skip this block silently there.

Second opinion

Intervision is peer consultation: equals looking at each other's work, not a supervisor looking down. Etymology says it plainly, inter- (between, among, together) against super- (from above). This skill brings a second coding agent in as that peer for an independent read. You hand it the work just done or just discussed, it looks with fresh eyes and a different training, and the two of you talk it through.

The peer here is Codex, reached through its codex exec command. It runs from the same repository, on its own login, with its own model behind it. That independence is the whole point; a peer trained the same way as you would only echo you.

Start on the cheap coding model returned by ${CLAUDE_PLUGIN_ROOT}/bin/codex-fast-coding-model. The helper reads codex debug models, prefers the visible Codex Spark or ultra-fast coding model, falls back to a visible mini coding model, and only uses the legacy Spark slug when the model catalog cannot be read. This keeps routine second opinions off the frontier session model without tying the skill to one OpenAI model slug. Escalate by rerunning the same handoff on the configured Codex default (omit --model, or name the stronger model explicitly) only when the cheap pass says the context is too large or uncertain, misses a concrete concern you can point to, the change is high-risk, or the operator asks for a deeper pass.

The peer has to be there

Before asking, confirm the peer exists:

command -v codex >/dev/null 2>&1 || { echo "codex CLI not found; intervision needs a peer to ask. Install and log in to Codex first."; }

If codex is missing, or codex login status shows you are not logged in, say so plainly and stop. There is no peer to ask, and pretending otherwise wastes the operator's time. This is the one hard precondition.

Then resolve the cheap first-pass model before any handoff:

: "${CLAUDE_PLUGIN_ROOT:?CLAUDE_PLUGIN_ROOT not set; intervision needs its installed plugin helper}"
CODEX_PEER_MODEL="$("${CLAUDE_PLUGIN_ROOT}/bin/codex-fast-coding-model" INTERVISION_CODEX_MODEL)" || {
  echo "no cheap Codex coding model found; stop instead of using the expensive Codex default"
  exit 1
}

INTERVISION_CODEX_MODEL can override the catalog choice for one run. Keep it to a plain model id; the helper rejects shell metacharacters.

Three ways to get the second opinion

Pick by what just happened. All three run through codex exec, and they combine: review a diff first, then go back and forth on whatever the review leaves open.

1. Check work just done, when there is a diff. Codex's review path reads the repository's changes directly, so point it at the change set that matches "what we just did":

DEFAULT=$(git symbolic-ref --quiet --short refs/remotes/origin/HEAD 2>/dev/null | sed 's#^origin/##')
if [ -z "$DEFAULT" ]; then
  CONFIGURED_DEFAULT=$(git config --get init.defaultBranch 2>/dev/null || true)
  if [ -n "$CONFIGURED_DEFAULT" ] && git rev-parse --verify "refs/heads/$CONFIGURED_DEFAULT" >/dev/null 2>&1; then
    DEFAULT=$CONFIGURED_DEFAULT
  fi
fi
[ -n "$DEFAULT" ] || { echo "cannot determine default branch from origin/HEAD or init.defaultBranch; pass an explicit --base" >&2; exit 1; }
codex exec --model "$CODEX_PEER_MODEL" review --uncommitted     # staged, unstaged, and untracked work
codex exec --model "$CODEX_PEER_MODEL" review --base "$DEFAULT" # everything on this branch against default
codex exec --model "$CODEX_PEER_MODEL" review --commit <sha>    # the changes in one commit

2. Weigh a design just discussed, when there is no code yet. Give Codex the context on stdin and keep it read-only so it reflects rather than edits. The -s flag rides on codex exec itself, not on a subcommand: neither review nor resume accepts it (resume inherits the session's sandbox, and passing -s there fails with error: unexpected argument '-s' found). Use a quoted heredoc so nothing in the pasted text is expanded by the shell:

codex exec --model "$CODEX_PEER_MODEL" -s read-only - <<'PROMPT'
Peer review this plan before we build it.
<paste the design, the trade-off, the open question, including the parts we are unsure about>
PROMPT

3. Go back and forth. A single answer is consultation; intervision is a conversation. Resume the same session to push on a point, defend your reasoning, or ask the peer to reconsider, again through a quoted heredoc. Do not add -s here; resume inherits the read-only sandbox from the session and rejects the flag:

codex exec resume --last - <<'PROMPT'
You flagged X as a race. The lock at <file:line> already serialises that path. Does that change your read?
PROMPT

To escalate, start a fresh default-model handoff with the same original prompt and the cheap peer's answer quoted underneath. Do not resume the cheap session for the escalation; resuming keeps that consultation on the same cheap model.

Keep resuming until each disagreement is either resolved or sharpened into a question the operator should decide. If two rounds pass with no movement, stop and surface the disagreement to the operator with both positions rather than looping.

How to do it well

The round-trip only earns its cost if the handoff is honest.

• Give the peer the real work, not a summary you are proud of. Point it at the actual diff, or paste the actual design with the shaky parts left in. A flattering summary buys a flattering review.
• Read for the disagreement, not the agreement. The peer agreeing is cheap and tells you little. The signal is where its independent read diverges from yours.
• Stay a peer, not a deferrer. A second agent is not an authority. When the peer is wrong, say so and push back. When it is right, concede plainly. Equals, in both directions.
• Keep the peer reviewing, not editing. codex exec review is used here to read a change set and report on it, and -s read-only keeps the design path from touching the tree. Let the peer propose; you and the operator decide what lands. Only widen the sandbox when the operator asks for it on purpose.
• Never expand the handoff through the shell. A pasted design or follow-up is arbitrary text and may contain $(...), backticks, or quotes. Feed it on stdin through a quoted heredoc (<<'PROMPT' ... PROMPT) into codex exec ... -, never as a double-quoted argument, so the shell passes it to the peer verbatim instead of executing part of it.

Bringing findings home

The peer's output is a pile of findings, not a to-do list. Each finding gets one honest fate:

• Fix it when it is real and the change earns its weight.
• Skip it on cost versus value when the fix would add more than it lifts, with a one-line reason.
• Reject it when it is hollow, with the evidence that makes it hollow.

Then surface the exchange to the operator: what the peer raised, what you did with each point, and where the two of you still disagree. Do not smooth the disagreements away. They are the most useful thing intervision produces, because they mark the spots neither agent can settle alone.