Antigravity harness crashes on startup when thinking level is set (wrong agy flag)

[ptone]

Bug

Any antigravity agent with a thinking level set crashes immediately on startup. The provisioner generates a wrapper script that passes --thinking-level <tier> to agy, but agy 1.1.25 does not have a --thinking-level flag. The correct flag is --effort.

The wrapper script has set -e, so the flag parse failure kills the container instantly.

Severity: High — every antigravity agent with any thinking level is broken.

Root cause

harnesses/antigravity/provision.py:494:

exec agy --dangerously-skip-permissions{f' --thinking-level {thinking_tier}' if thinking_tier else ''} "$@"

Should be --effort not --thinking-level.

Secondary: tier count mismatch

_resolve_thinking_tier() (lines 38-47) maps to 4 tiers including "Minimal", but agy --effort only accepts 3 values: low|medium|high. A thinking_level of 0-24 produces "Minimal" which agy doesn't recognize.

Tertiary: case mismatch

The mapper produces capitalized values (High, Medium, Low) while agy documents lowercase (high, medium, low). agy is case-insensitive so this doesn't crash, but it's inconsistent.

Fix

Two changes in harnesses/antigravity/provision.py:

1. Fix _resolve_thinking_tier() (lines 38-47) — collapse to 3 tiers, lowercase:

def _resolve_thinking_tier(level: int) -> str:
    level = max(0, min(100, level))
    if level >= 75:
        return "high"
    if level >= 50:
        return "medium"
    return "low"

2. Fix wrapper template (line 494) — --thinking-level → --effort:

exec agy --dangerously-skip-permissions{f' --effort {thinking_tier}' if thinking_tier else ''} "$@"

Confirmed by testing

Inside container image scion-antigravity:latest (agy 1.1.25):

• agy --thinking-level High → "flags provided but not defined: -thinking-level" (FAILS)
• agy --effort high → flag accepted (WORKS)
• agy --help shows: --effort Reasoning effort for the current CLI session (low|medium|high)

Files

• harnesses/antigravity/provision.py:494 — wrong flag name in wrapper template
• harnesses/antigravity/provision.py:38-47 — tier mapper with 4 tiers (agy only has 3)

Reported by instance-investigator on scion-sagan (agent ag32).