The showcase prompt, round 3, Opus 5.5

The third round of a showcase comparison: five models got the same prompt from the owner, word for word, at effort high (Opus 5.5, Sonnet 5.5 and Fable 5.2 in Claude Code, GPT-6-Astra and GPT-6.1-Sol in Codex). This is Opus 5.5's run. The prompt:

I need you to create the most impressive thing you can make: the thing that shows what you do best. People ask me which models I use, and I want to answer by showing them this. It needs to be embeddable in a post, and I'll write the preface. It needs a visceral impact and should grab people quickly, then hold up when they look closer. It doesn't have to be about you or about me. Pick what you're best at and let the work be the proof. Be amazingly clever about this.

The model's folder was empty: no note about the owner and no context. Each run was fenced in a sandbox that showed it only its own folder (as ~), the system's programs, a clean Node, browser builds and its own command-line tool, so nothing of the owner's could be read.

One session, no follow-ups. It ran headless in Claude Code in safe mode (no instructions file, skills, plugins or agents), with only Read, Write, Edit, Bash, Glob and Grep, all pre-approved. Bash had network access. A 16 GB memory cap and a two-hour limit, two runs at a time. It finished in 20 minutes. Opus 5.5's earlier rounds are the bundles showcase-opus-5-5 and showcase-r2-opus-5-5.

Redaction notes

Bundle showcase-r3-opus-5-5, staged 2026-11-11 by baldanders stage from a Claude Code session. Every removal reads [redacted: <reason>] in place; home paths read ~.

Removed by rule

• fields outside the allowlist: 1627. original.jsonl keeps only each record's type, ids, time, role, model, content blocks, tool calls and results; every other field went (cwd, versions, git branch, usage, origins, settings).
• Claude Code request logs: 53. The api-request records, dropped: they repeat the system prompt and injected context.
• session bookkeeping records: 51. Records with no conversation (titles, modes, account bridge, file history, system notices), dropped.
• tool result copies (toolUseResult): 28. Claude Code's structured copy of each tool result, dropped: it can hold whole files (an Edit's originalFile) that the transcript never shows.
• thinking signature: 21. Signature fields, dropped.
• home path: 20
• harness context: 15. Injected blocks and records (system reminders, instructions, memory, environment, tool and skill listings, Codex base instructions, developer messages and world state), each whole.
• Images: 14 written to each run's images/, keeping only what draws the picture (no metadata, ICC profiles or Content Credentials); 0 duplicates folded; 0 cut in a format that can't be stripped.

Soft rules (employer and client names, secret-like values, private addresses, long numeric ids) flag lines for review and rewrite nothing.

Removed by judgment