Audit PRs #52 #53 #54 code exec harness changes

[cbusillo]

Current Status

Created from parent audit plan #63.

Scope

Review the code exec behavior harness and GitHub auth isolation changes for intent, quality, and whether they affect runtime agent behavior. Parent: #63. PRs: #52 #53 #54

Review Checklist

• Intent: why did this PR/group exist?
• Surface: what files and runtime paths changed?
• Risk: compaction, token pressure, agent behavior, auth, repo workflow, or other?
• Verdict: keep as-is, keep with rewrite, defer, or drop.
• Validation evidence recorded.

[cbusillo]

Harness Restore Update - 2026-05-13

Restored the code exec behavior harness onto the known-good v0.6.98 stabilization branch as original cherry-picked commits:

• PR Add code exec behavior harness #52 / 99cff8cc18e93108c28290d887e91004edec27ee - add tools/code-exec-harness
• PR Fix code exec harness auth isolation #53 / c3e69d9626ca19da6c6a6a6f22efc1d1a147162e - fix harness GitHub auth isolation
• PR Clear inherited gh config in code exec harness #54 / 4625fc0f15b4688de532411e298b69e7bcd68eac - clear inherited GH_CONFIG_DIR

Local branch now includes these commits after the v0.6.98 baseline metadata commit.

Validation run:

python3 -m py_compile tools/code-exec-harness/harness.py
python3 tools/code-exec-harness/harness.py tools/code-exec-harness/scenarios/github-plan-smoke.json --dry-run --skill-root /Users/cbusillo/Developer/codex-skills --inherit-auth

Dry-run output directory:

/Users/cbusillo/Developer/code/.tmp/code-exec-harness/20260513-142714-github-plan-smoke

Not restored yet:

• stashed harness-only additions for command-start/order assertions
• token scanner PRs Add session token efficiency scanner #55/Filter token scan usage by account #57
• image-heavy history compaction PR Compact image-heavy history before reuse #56
• skill trigger PRs Enforce binding skill trigger guidance #58/Enforce independent skill trigger handling #59/Allow grouped skill prefix commands #60
• compaction WIP stash

Next step: design or restore the smallest harness scenario that reproduces the image-heavy history/token-burn problem before auditing PR #56.