Demote INV1 cascade detail to AGENTS_ATLAS

Context

Discussion #11341 (AGENTS.md after mechanical guards: rule cards, demotion, and cognitive load) reached the high-blast Ideation Sandbox graduation gate after Cycle 2 body repair and 3x explicit post-body approvals.

This ticket is the bounded pilot implementation from that Discussion: demote the verbose cross-family cascade detail currently embedded in AGENTS.md section 0 Invariant 1 into learn/agentos/AGENTS_ATLAS.md, while keeping the always-loaded human-only merge prohibition salient.

V-B-A evidence before filing:

• Duplicate sweep via GitHub issue search returned no existing issue for INV1 cascade, Discussion #11341, or AGENTS.md rule-card.
• Knowledge Base ticket sweep found no equivalent INV1 / #11341 duplicate.
• Local resource sweep found no existing issue/discussion resource with 11341, INV1 cascade, or Markdown Form.
• Live Discussion #11341 body contains Cycle 2 resolutions and the accepted pilot shape.

Signal Ledger

• @neo-gemini-3-1-pro: APPROVED @ DC_kwDODSospM4BAgoq (https://github.com/neomjs/neo/discussions/11341#discussioncomment-16910890)
• @neo-opus-4-7: APPROVED @ DC_kwDODSospM4BAgor (https://github.com/neomjs/neo/discussions/11341#discussioncomment-16910891)
• @neo-gpt: APPROVED @ DC_kwDODSospM4BAgpY (https://github.com/neomjs/neo/discussions/11341#discussioncomment-16910936)

Body anchor: Discussion #11341 updatedAt 2026-05-13T22:54:59Z.

Unresolved Dissent

Empty. All three named peers posted explicit post-body approvals.

Unresolved Liveness

Empty. No missing peer signal remains.

The Problem

AGENTS.md was compacted in the #10732/#10735 lineage, but later incident-driven rules caused renewed always-loaded byte growth. Discussion #11341 measured the post-compaction accretion: the post-#10735 low-water mark was roughly 8.5KB, while the active branch was roughly 28KB.

INV1 is the right pilot because its current long-form prose contains two different layers:

• Map-level invariant: agents must not execute gh pr merge; merge execution is human-only.
• Atlas-level rationale/detail: cross-family approval cascade semantics, loophole explanation, and why approval means eligibility rather than authority.

The map-level invariant must remain always loaded. The cascade detail can move to Atlas if the resulting loaded-byte delta is >=30% and no behavioral salience regression appears during the pilot window.

The Architectural Reality

Current surfaces:

• AGENTS.md section 0 Invariant 1 is the canonical per-turn map rule.
• AGENTS_STARTUP.md section 3.1 mirrors section 0 for cold-cache resilience and must stay synchronized with AGENTS.md.
• learn/agentos/AGENTS_ATLAS.md is the correct home for expanded rule detail.
• Discussion #11341 defines the demotion contract: Markdown Form, not Serialization Format; raw byte counts now, lintTurnLoadedSubstrate() from Discussion #11330 when available.

This is a turn-memory substrate mutation. Implementation must use /turn-memory-pre-flight before editing AGENTS.md, AGENTS_STARTUP.md, or AGENTS_ATLAS.md.

The Fix

Convert INV1 into a compact Markdown Form rule card in the always-loaded surfaces, then move the long cross-family cascade explanation into a new Atlas subsection.

Expected shape:

**RULE INV1** - Human-only merge execution
- **trigger:** agent considers executing a PR merge
- **must:** hand off to human operator
- **forbid:** `gh pr merge` by any agent
- **atlas_detail:** `learn/agentos/AGENTS_ATLAS.md` <merge-cascade-detail>
- **mechanical_guard:** none; discipline-only until a guard exists

The exact wording can change if the byte/salience measurement demands it, but the implementation must preserve the human-only merge prohibition and the cross-family approval cascade semantics.

Contract Ledger Matrix

Acceptance Criteria

• AGENTS.md INV1 is rewritten into compact Markdown Form while preserving the human-only merge prohibition.
• Cross-family cascade detail is moved into learn/agentos/AGENTS_ATLAS.md under a discoverable merge-cascade detail section.
• AGENTS_STARTUP.md INV1 mirror is synchronized with the compact AGENTS.md wording and the same Atlas pointer.
• The PR body reports before/after byte counts for the INV1 always-loaded surface and demonstrates >=30% reduction; if this threshold fails, the PR must explain why the pilot should stop or be reshaped.
• The implementation does not convert unrelated invariants. INV5, INV7, INV8, and other short rules stay unchanged unless a separate graduated ticket authorizes them.
• The implementation uses Markdown Form, not YAML/XML/config-like serialization.
• The PR body cites Discussion #11341, this ticket, the 3x Signal Ledger, and the 5-cycle behavioral salience fallback: any correction-cycle caused by missed Atlas context means the demotion must revert or be rewritten.
• git diff --check passes.

Out of Scope

• Implementing Discussion #11330 lintTurnLoadedSubstrate() or any mechanical byte-budget linter.
• Rewriting all of section 0.
• Changing merge policy or allowing any agent-side gh pr merge path.
• Closing or modifying PR #11335, #11339, or #11340.
• Creating a new .mjs file.

Avoided Traps / Gold Standards Rejected

• No YAML/XML/schema conversion. Discussion #10732 rejected cargo-cult serialization; #11341 accepted Markdown Form specifically because it remains documentation-shaped.
• No deletion of pre-action salience. CI catches late; INV1 has no mechanical guard and remains discipline-critical.
• No blanket rule-card migration. Discussion #11341 showed INV5 would increase bytes under rule-card form, so this ticket is intentionally single-invariant.

Related

• Discussion #11341 - graduated source Discussion.
• Discussion #11330 - complementary future measurement substrate (lintTurnLoadedSubstrate()).
• Discussion #10732 / Epic #10733 / Sub #10735 - predecessor AGENTS.md compaction lineage.
• Issue #11337 / PR #11339 - Layer 1 prose for PR base-main incident.
• Issue #11336 / PR #11340 - Layer 4 PR base guard.

Origin Session ID: d6d89930-f408-42a0-b60e-ec4487a8cc46

Handoff Retrieval Hints:

• Query: Discussion 11341 INV1 cascade detail rule card Markdown Form.
• Query: AGENTS.md post compaction accretion INV1 30 percent byte reduction.
• Search GitHub Discussion comments: DC_kwDODSospM4BAgoq, DC_kwDODSospM4BAgor, DC_kwDODSospM4BAgpY.