jr-rails-second-opinion

name	jr-rails-second-opinion
description	Get a Rails-flavored second opinion on a branch, PR, or working tree by delegating to a locally-installed agentic CLI (claude, codex, opencode, gemini, aider, etc.). Self-contained: no MCP server required.
triggers	["/jr-rails-second-opinion","jr-rails-second-opinion","rails second opinion","rails sparring partner","review my Rails branch with codex","review my Rails branch with opencode","codex review my branch","opencode review my branch","use codex to review","use opencode to review","use gemini to review","use aider to review","use claude to review","second opinion on this branch","external Rails review","have another agent review this","get another model to review","review my Rails work with another CLI","dual-CLI review","multi-CLI review","cross-CLI sparring"]

Rails Second Opinion (Local Agentic CLI)

Delegate review of Rails work (uncommitted diff, branch, or PR) to a locally-installed agentic CLI. Wraps the CLI in a structured Self-Review → External Review → Reconcile → Synthesize loop with H/M/L severity gating, mirroring the consult-outside-expert workflow but without MCP dependence.

Read @references/guide.md and follow it. Do not proceed without it.

Invocation

• /jr-rails-second-opinion (review uncommitted changes; default)
• /jr-rails-second-opinion <branch> (review <branch> diff vs main)
• /jr-rails-second-opinion <PR#> (fetch PR with gh, review the diff)
• /jr-rails-second-opinion --multi (run review through 2+ CLIs in parallel and reconcile)

Workflow Overview

1. CLI Discovery (Required First Step)

Probe for installed agentic CLIs. Do not trust the inherited $PATH or $SHELL — Claude Code's Bash tool spawns a non-login shell that misses fish/zsh PATH entries and most version-manager shims (asdf, mise, volta, fnm, bun, pnpm). Worse, $SHELL may report /bin/zsh even when the user actually runs fish (macOS user record defaults to zsh; fish is exec'd from .zshrc). Probe every installed user shell, merge their login PATHs, then augment with common install dirs:

# Don't trust $SHELL — on macOS it often reflects the user-record default (zsh)
# even when the user actually runs fish via `exec fish` from .zshrc. Probe
# every installed user shell and merge their login PATHs.
PATHS_TO_TRY=()
for sh in fish zsh bash; do
  command -v "$sh" >/dev/null 2>&1 || continue
  case "$sh" in
    fish) p=$("$sh" -l -c 'string join : -- $PATH' 2>/dev/null) ;;
    *)    p=$("$sh" -l -c 'printf %s "$PATH"' 2>/dev/null) ;;
  esac
  [ -n "$p" ] && PATHS_TO_TRY+=("$p")
done
LOGIN_PATH=$(IFS=:; echo "${PATHS_TO_TRY[*]}")
[ -z "$LOGIN_PATH" ] && LOGIN_PATH="$PATH"

EXTRA_DIRS="$HOME/.local/bin:$HOME/.npm-global/bin:$HOME/.bun/bin:$HOME/.cargo/bin:$HOME/.deno/bin:$HOME/.asdf/shims:$HOME/.mise/shims:$HOME/Library/pnpm:/opt/homebrew/bin:/usr/local/bin"
SEARCH_PATH="$LOGIN_PATH:$EXTRA_DIRS"

for cmd in claude codex opencode gemini aider mods cursor-agent llm sgpt goose; do
  bin=$(PATH="$SEARCH_PATH" command -v "$cmd" 2>/dev/null) || continue
  echo "$cmd -> $bin"
done

Then call AskUserQuestion with the detected CLIs as options:

• If 0 found, ask the mediator before escalating to install. They may have a CLI at a non-standard path — accept an absolute path via the "Other" answer. Only suggest installing (brew install codex, npm i -g opencode-ai) after they confirm nothing is installed.
• If 1 found, still confirm it as the choice.
• If 2+ found, list them as options. Add an "all of them (multi mode)" option when --multi is passed.

Reuse the resolved $SEARCH_PATH (or the absolute path) when invoking the CLI later — the same shell-context issue applies to invocation, not just detection.

2. Scope

Determine review scope:

• Default (no arg): uncommitted changes (git diff + untracked summary).
• Branch: git diff <base>...<branch> where base is main (or current upstream).
• PR#: gh pr checkout <num> then branch flow, or fetch the PR diff via gh pr diff.

3. Brief Construction

Build the brief passed to the CLI. Force the H/M/L severity rubric and the five Rails-flavored review dimensions: architecture (skinny controllers, rich models, callback design), quality (Ruby idiom, naming, anti-patterns), performance (N+1, indexes, eager loading), testing (coverage, integration/unit balance), security (strong params, mass assignment, Brakeman class issues). Include the project's hard rule: never recommend service objects as a solution.

See references/guide.md for the full brief template.

4. Run Review

Invoke the chosen CLI with its review-style command. Per-CLI invocations live in references/cli-invocations.md. Capture stdout to the working log.

5. Self-Review + Reconcile + Synthesize

Implementer (you) does a parallel self-review, then reconciles with the CLI's findings. Produce a synthesis with Consensus / Disagreements / Actions / Gate Status. Wait for mediator approval before acting.

6. Act + Iterate

Address agreed actions. Open a Round 2 if needed (re-run CLI on the updated artifact, capture deltas only). Stop on convergence: no open H, all M either fixed or accepted.

7. Cleanup

Delete the working log (second-opinion.md) after final attestation. The improved artifact is the deliverable, not the log.

Hard Rules

Inherit from jr-rails-review: never recommend service objects (*Service, *Manager, *Handler, *Processor, *Creator, .call PORO patterns). Pass this rule into the second-opinion CLI's brief so it doesn't suggest them either. When extraction is needed, prefer domain models, form objects, query objects, concerns, DCI contexts, or callback extraction.

Never act on a CLI finding without mediator approval. The CLI is a signal generator, not a judge. Decisions stay with the human.

Do not pipe secrets to the CLI. Brief construction must scrub .env, config/credentials/*, and any file Brakeman flags as containing secrets.

File Layout

jr-rails-second-opinion/
├── SKILL.md                       # This file (entry point)
└── references/
    ├── guide.md                   # Workflow detail (load when starting a session)
    ├── cli-invocations.md             # Per-CLI invocation patterns + flags (load when picking a CLI)
    └── second-opinion-log-template.md # Working-log skeleton (copy when starting a session)

Load reference files only when you need them. Progressive disclosure keeps the entry point cheap.