Antigravity Payload Capture and Cross-Harness Validation

Context As part of the structural fix for the 24KB truncation limit (Epic #11411), we must empirically verify that the new loading paths and substrate sizes survive across all supported LLM provider harnesses.

The Problem We need a durable public record of the raw Antigravity payload to prove exactly how it truncates the files, and we must ensure our Progressive Disclosure pivot doesn't negatively impact Claude Code or Codex memory loading.

The Architectural Reality We need empirical proof before closing the Epic.

The Fix Execute a manual or automated payload capture on the Antigravity harness and validate the context loading on Codex/Claude.

Acceptance Criteria

• Raw Antigravity payload is captured and documented, definitively proving the 24KB truncation boundary and injection order.
• The reason for ANTIGRAVITY_RULES.md silently dropping is investigated and documented.
• Cross-harness non-regression is validated: verify that Codex and Claude still properly load the shrunk AGENTS.md and trigger the new Atlas files correctly.

Out of Scope

• Implementing the CI guard (handled in Sub 1).
• Editing AGENTS.md (handled in Sub 2).

Related

• Parent Epic: #11411

Origin Session ID: 188acb85-b41e-435c-94ee-0cc9944d4c97