GPT-5.5 / Codex parity maintainer notes

This note explains how to review the GPT-5.5 / Codex parity program as four merge units without losing the original six-contract architecture.

Merge units

PR A: strict-agentic execution

Owns:

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  executionContract
• GPT-5-first same-turn follow-through
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  update_plan
  as non-terminal progress tracking
• explicit blocked states instead of plan-only silent stops

Does not own:

• auth/runtime failure classification
• permission truthfulness
• replay/continuation redesign
• parity benchmarking

PR B: runtime truthfulness

Owns:

• Codex OAuth scope correctness
• typed provider/runtime failure classification
• truthful
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  /elevated full
  availability and blocked reasons

Does not own:

• tool schema normalization
• replay/liveness state
• benchmark gating

PR C: execution correctness

Owns:

• provider-owned OpenAI/Codex tool compatibility
• parameter-free strict schema handling
• replay-invalid surfacing
• paused, blocked, and abandoned long-task state visibility

Does not own:

• self-elected continuation
• generic Codex dialect behavior outside provider hooks
• benchmark gating

PR D: parity harness

Owns:

• first-wave GPT-5.5 vs Opus 4.6 scenario pack
• parity documentation
• parity report and release-gate mechanics

Does not own:

• runtime behavior changes outside QA-lab
• auth/proxy/DNS simulation inside the harness

Mapping back to the original six contracts

Review order

1. PR A
2. PR B
3. PR C
4. PR D

PR D is the proof layer. It should not be the reason runtime-correctness PRs are delayed.

What to look for

PR A

• GPT-5 runs act or fail closed instead of stopping at commentary
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  update_plan
  no longer looks like progress by itself
• behavior stays GPT-5-first and embedded-Pi scoped

PR B

• auth/proxy/runtime failures stop collapsing into generic “model failed” handling
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  /elevated full
  is only described as available when it is actually available
• blocked reasons are visible to both the model and the user-facing runtime

PR C

• strict OpenAI/Codex tool registration behaves predictably
• parameter-free tools do not fail strict schema checks
• replay and compaction outcomes preserve truthful liveness state

PR D

• the scenario pack is understandable and reproducible
• the pack includes a mutating replay-safety lane, not only read-only flows
• reports are readable by humans and automation
• parity claims are evidence-backed, not anecdotal

Expected artifacts from PR D:

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  qa-suite-report.md
  /
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  qa-suite-summary.json
  for each model run
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  qa-agentic-parity-report.md
  with aggregate and scenario-level comparison
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  qa-agentic-parity-summary.json
  with a machine-readable verdict

Release gate

Do not claim GPT-5.5 parity or superiority over Opus 4.6 until:

• PR A, PR B, and PR C are merged
• PR D runs the first-wave parity pack cleanly
• runtime-truthfulness regression suites remain green
• the parity report shows no fake-success cases and no regression in stop behavior

mermaid
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flowchart LR
    A["PR A-C merged"] --> B["Run GPT-5.5 parity pack"]
    A --> C["Run Opus 4.6 parity pack"]
    B --> D["qa-suite-summary.json"]
    C --> E["qa-suite-summary.json"]
    D --> F["qa parity-report"]
    E --> F
    F --> G["Markdown report + JSON verdict"]
    G --> H{"Pass?"}
    H -- "yes" --> I["Parity claim allowed"]
    H -- "no" --> J["Keep runtime fixes / review loop open"]

The parity harness is not the only evidence source. Keep this split explicit in review:

• PR D owns the scenario-based GPT-5.5 vs Opus 4.6 comparison
• PR B deterministic suites still own auth/proxy/DNS and full-access truthfulness evidence

Quick maintainer merge workflow

Use this when you are ready to land a parity PR and want a repeatable, low-risk sequence.

1. Confirm evidence bar is met before merge:
   • reproducible symptom or failing test
   • verified root cause in touched code
   • fix in the implicated path
   • regression test or explicit manual verification note
2. Triage/label before merge:
   • apply any
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     r:*
     auto-close labels when the PR should not land
   • keep merge candidates free of unresolved blocker threads
3. Validate locally on the touched surface:
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     pnpm check:changed
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     pnpm test:changed
     when tests changed or bug-fix confidence depends on test coverage
4. Land with the standard maintainer flow (
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   /landpr
   process), then verify:
   • linked issues auto-close behavior
   • CI and post-merge status on
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     main
5. After landing, run duplicate search for related open PRs/issues and close only with a canonical reference.

If any one of the evidence bar items is missing, request changes instead of merging.

Goal-to-evidence map

Reviewer shorthand: before vs after

Related

• GPT-5.5 / Codex agentic parity