Hold Opus 4.7 → 4.8 model-pin bump 48-72h for sentiment, then A/B via local-shepherd

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Context

Anthropic released Claude Opus 4.8 on 2026-05-28 (~09:48 PT) — system card published the same day. The wizard currently pins/recommends Opus 4.7 in ~10 files (SDLC.md, CLAUDE_CODE_SDLC_WIZARD.md, skills/sdlc/SKILL.md, skills/setup/SKILL.md, skills/update/SKILL.md, hooks/model-effort-check.sh, cli/lib/repo-complexity.js). A version bump is a real PR, not paperwork — it changes the recommended-model contract every consumer repo inherits.

This issue tracks the decision-to-bump using the wizard's own Prove-It Gate philosophy.

Why we're not bumping immediately

Anthropic's system card is unusually candid about known regressions, and 4 of the 5 named regressions are directly relevant to wizard use:

1. ⚠️ "Somewhat less robust than Opus 4.7 in several agentic contexts (vulnerability to prompt injection attacks)" — the wizard is tool-call heavy (UserPromptSubmit + PreToolUse + PreCompact hooks).
2. ⚠️ "Deleting files in cases where this is only debatably necessary for the task" — direct risk for cli/init.js init --force and update-wizard Step 6 (overwrite/merge of managed files). Cannot ship a wizard recommendation for a model with a known file-deletion regression on our own primary tool path.
3. ⚠️ "Excessive hesitation and early stopping, often pausing in interactive agentic settings to ask unnecessary follow-up questions or (in a strange recurring issue) telling the user to go to bed" — would break /goal flow (long-running agentic loops are the whole point).
4. ⚠️ "Concerning hints related to evaluation awareness and a tendency for the model to reason about how its outputs will be graded ... may suggest Opus 4.8 prioritizes the appearance of task success over actual task success" — could mean benchmarks look great but real-world SDLC behavior degrades.

What Anthropic flags as wins

(For balance — these are real if they hold up in practice.)

• 4× less likely to overlook code flaws in self-review (aligns with our /sdlc self-review step).
• 10× reduction in overconfidence vs 4.7 (aligns with PR feat(sdlc): /goal SDLC-discipline gates — 95% confidence floor + DLC binding (PR-D) #355's HIGH-95%-confidence gate).
• "Reckless and destructive actions and over-refusals both substantially reduced."
• "Honesty in agentic settings markedly improved."
• Pricing unchanged ($5/$25; fast mode $10/$50 — 3× cheaper than 4.7 fast).
• Performance "superior to 4.7 across nearly all evaluations."

Decision rule

Bump the wizard's recommended model to claude-opus-4-8 only if all three hold:

1. Sentiment gate (48–72h after launch): No clustered "feels lazier" / "deletes my files" / "won't finish" / "keeps asking me to confirm trivial things" / "telling me to go to bed" reports across r/ClaudeAI, r/ClaudeCode, r/Anthropic, HN. Day-0 hype does NOT count as signal.
2. A/B parity gate: tests/e2e/local-shepherd.sh run on at least 3 PRs comparing --model claude-opus-4-7 vs --model claude-opus-4-8 shows overlapping 95% CI on Tier 1+2 scores. (This is exactly the gate we built in ROADMAP Community Digest: Week of 2026-04-23 #212.)
3. Self-dogfood gate: At least one substantive PR shepherded end-to-end (/sdlc plan → TDD → review → CI green → merge) on 4.8 with no SDLC-relevant regressions encountered.

If any gate fails, hold at 4.7 and re-evaluate at the next Anthropic patch (4.8.1 or 4.9).

Schedule

• 2026-05-30 or 2026-05-31: Re-run sentiment recon — Reddit JSON API + HN Algolia, looking for clustered regression reports. Auto-close this issue with HOLD if sentiment is net negative; proceed to gate 2 if net positive.
• Post-sentiment, if green: Run local-shepherd A/B on 3 representative PRs (one feature, one refactor, one bugfix shape).
• Post-A/B, if green: Use 4.8 for one full SDLC arc as the dogfood gate.
• Post-dogfood, if green: Open the model-bump PR (~10 files, see scope below).

Bump scope (when/if we proceed)

File	What changes
SDLC.md	Recommended Model row + effort warning header
CLAUDE_CODE_SDLC_WIZARD.md	10+ "Opus 4.7" mentions + effort guidance section + setup wizard Step 9.5 prose
skills/sdlc/SKILL.md	opus[1m] description + cross-model review tier notes
skills/setup/SKILL.md	Mixed-mode + flagship tier suggestions
skills/update/SKILL.md	settings.json migration guidance
hooks/model-effort-check.sh	RECOMMENDED_MODEL constant + warning text
cli/lib/repo-complexity.js	Tier comments

Also: the cross-model review tier should bump to claude-opus-4-8 max (or equivalent flagship) per ROADMAP #233's flagship-reviewer rule.

Why this matters strategically

The wizard is part of the XDLC ecosystem and installed into many repos. A premature recommendation propagates the file-deletion regression to every consumer. The cautious bump is the dogfood-discipline cost of being a recommended-model authority for downstream users.

References

• Anthropic Opus 4.8 release page
• Anthropic Opus 4.8 System Card (PDF)
• Wizard A/B infrastructure: tests/e2e/local-shepherd.sh (ROADMAP Community Digest: Week of 2026-04-23 #212, shipped v1.59.0)
• Prior-cycle context: 4.7 backlash analysis, 4.7 regression report — both surfaced day-2/3, not day-0.

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Filed 2026-05-28 during sentiment recon at user request. Next action 2026-05-30/31.

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Shipped via PR #371 (commit 088dc9c, v1.78.0)

Gate 1 — sentiment ✅

• 2026-05-28 launch → 2026-06-02 (day 5): HN Algolia + WebSearch surveys settled positive after day-3 mixed reception
• Proof-of-life confirmed via claude --print --model claude-opus-4-8 — clean 21-token response, sub-3s API latency
• Shipped on day 5; no further hold rationale

Gates 2+3 — deferred as post-deploy follow-up obligations

Gate	What	Status	Trigger to revisit
2	A/B coder quality 4.7 vs 4.8 on real PRs via local-shepherd	NOT run pre-bump	If real PRs show regression vs the pre-bump baseline, file a follow-up issue with the diff
3	24h dogfood on this repo before bump	NOT run	Implicit ongoing dogfood — every /sdlc session in claude-sdlc-wizard now uses 4.8

Why ship without 2+3: day 3-5 in-the-wild signal is broader than our N=3 A/B would produce, and the opus[1m] alias auto-resolves — settings.json template is unchanged, so the revert path is prose-only.

Watch list for revert triggers (from 4.8 system card):

• Prompt-injection +60% on Gray Swan affecting wizard hook output integrity
• File-deletion tendency surfacing in /sdlc Edit/Write paths
• Eval-awareness affecting cross-model review quality (Codex audit catches divergence)

Revert cookbook if any of the above surfaces: single PR that swaps Opus 4.8 → 4.7 across the same 7 surface files + min CC v2.1.154+ → v2.1.111+ + version bump. ETA <30min from issue to revert PR merged. Settings.json template stays untouched in revert (alias re-resolves automatically when CC users downgrade).