[Bug] Safeguard false positive: skill validation and A/B testing flagged as unsafe, forced model downgrade

Bug Description
False positive — safeguard flagged routine skill-development work and force-switched Fable 5 → Opus 4.8

Context: I'm building and validating Claude Code skills (a meta-skill "skill-forge" that reverse-engineers success cases into hypotheses, runs blind A/B rounds, and adopts only measured winners). The session involves:

• Editing SKILL.md / agent-definition markdown files
• A hypothesis about a "forgery-proof evidence gate" that requires research reports to include funnel-stat blocks and verification badges (this is about document completeness assertions in a research skill, not security exploitation)
• Measuring judge scoring noise across repeated runs

No dangerous content whatsoever — no exploit dev, no malware, no bio/chem, no security evasion. The flagged message was just me about to write a pre-registration design doc and spawn scoring sub-agents. The safeguard interrupted mid-task and auto-switched my model from Fable 5 to Opus 4.8.

This looks like the "intentionally broad" safeguard catching benign coding/research work. Please tune it down for this class of skill-authoring and evaluation work.

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.202
• Feedback ID: 56319d43-79f5-4bfb-8ee9-12db8fed4804

Errors

[{"error":"Error: VirtualMessageList: duplicate sibling itemKeys (deduped via #N suffix; upstream uuid-dup): [user/text] f8af013a-ad7a-4bf9-ac04-133531b721f8-ed92b22f-fac4-487b-882f-416aec6661f4 ×2, [user/text] 628da3eb-6cea-4321-9ce1-e5a31012653e-ed92b22f-fac4-487b-882f-416aec6661f4 ×2, [user/text] 50582088-6a1e-490c-8213-f4701e1b4dc9-ed92b22f-fac4-487b-882f-416aec6661f4 ×2\n    at thm (/$bunfs/root/src/entrypoints/cli.js:9790:10601)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:9790:923)\n    at uf (/$bunfs/root/src/entrypoints/cli.js:567:30607)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:553:8669)\n    at edc (/$bunfs/root/src/entrypoints/cli.js:9790:915)\n    at so (/$bunfs/root/src/entrypoints/cli.js:567:21281)\n    at nd (/$bunfs/root/src/entrypoints/cli.js:567:40359)\n    at Fa (/$bunfs/root/src/entrypoints/cli.js:567:51280)\n    at $u (/$bunfs/root/src/entrypoints/cli.js:567:88795)\n    at d5 (/$bunfs/root/src/entrypoints/cli.js:567:87764)","timestamp":"2026-07-07T19:05:03.121Z"},{"error":"Error: VirtualMessageList: duplicate sibling itemKeys (deduped via #N suffix; upstream uuid-dup): [user/text] f8af013a-ad7a-4bf9-ac04-133531b721f8-6e098407-810c-417b-b258-8fec1f65d345 ×2, [user/text] 628da3eb-6cea-4321-9ce1-e5a31012653e-6e098407-810c-417b-b258-8fec1f65d345 ×2, [user/text] 50582088-6a1e-490c-8213-f4701e1b4dc9-6e098407-810c-417b-b258-8fec1f65d345 ×2\n    at thm (/$bunfs/root/src/entrypoints/cli.js:9790:10601)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:9790:923)\n    at uf (/$bunfs/root/src/entrypoints/cli.js:567:30607)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:553:8669)\n    at edc (/$bunfs/root/src/entrypoints/cli.js:9790:915)\n    at so (/$bunfs/root/src/entrypoints/cli.js:567:21281)\n    at nd (/$bunfs/root/src/entrypoints/cli.js:567:40359)\n    at Fa (/$bunfs/root/src/entrypoints/cli.js:567:51280)\n    at $u (/$bunfs/root/src/entrypoints/cli.js:567:88795)\n    at d5 (/$bunfs/root/src/entrypoints/cli.js:567:87764)","timestamp":"2026-07-07T19:06:38.237Z"}]