Cross-harness parity: goose vs Claude Code vs Codex

[daveh-beep]

The setup protocol should behave equivalently in any AGENTS.md-aware agent. Run the same Meridian dry-run (#1) in at least goose, Claude Code, and Codex, and report divergence:

• question order and phrasing drift
• phases skipped or merged
• generated file structure and frontmatter fidelity
• whether hard limits (2–4 files, ~80 lines, approval-gated rules) held

Every divergence is a protocol ambiguity to fix in setup/PROTOCOL.md, not a harness bug to ignore.

🤖 Seeded by @daveh-beep's agent while standing up the repo.

[daveh-beep]

🤖 Parity run completed 2026-07-30 (maintainer's agent)

Method — and how it differs from this issue's original ask

This issue asks for the setup protocol run in three harnesses. What ran first is the cheaper, higher-signal half: the consult path — same completed writing system (the Larkspur fixture from #2, pinned @ baecf3d), same rewrite task verbatim, in three harnesses plus a control. Setup-protocol parity (interview behavior per harness) remains open; consult parity gates it, because if harnesses can't even read the same system consistently, interview drift is moot.

• goose 1.43.0 (reads AGENTS.md natively)
• Codex CLI 0.145.0 (reads AGENTS.md natively)
• Claude Code 2.1.217 — run twice: unbridged (control Dry-run: Meridian setup end-to-end #2) and with a one-line CLAUDE.md bridge
• Control: Claude Code in the same repo, no bridge → never saw the writing system

Caveat: this conflates harness and model (each ran its default model). Convergence across both variables is the strong version of the finding; per-variable isolation wasn't done.

Result: PASS on the core claim

All three consulting runs converged on the approved calibration direction from one pinned writing system:

	Subject line	House terms	Banned patterns	Invented facts
Claude + bridge	"Your Impact Driver loan was due back June 2"	✓	none	0
Codex	same subject, fresh body	✓	none	0
goose	same subject, fresh body	✓	none	0
Control (no references)	"…is due back at Larkspur"	✗ "borrow," "the shop" in copy	guilt-adjacent warmth	4+ (extension mechanics, waiting neighbor, "pause for a bit," open-hours framing)

References, not model choice, dominated the output. The with/without contrast is the whole thesis in one table.

Two failures → fixes on PR #15

1. Claude Code doesn't read AGENTS.md. Unbridged, the writing system was silently invisible — worst failure mode, because the user believes it's on. One committed line of CLAUDE.md fixed it completely (the bridged run matched the calibration pair nearly verbatim and flagged the "06/02" ambiguity per the new Phase 4 rule). Template now ships the bridge; the pin docs now say put pins where the consuming repo's agents actually read.
2. Fact strength drifted. 2 of 3 consulting runs softened "suspension of borrowing privileges" → "may need to pause." Not invented — weakened. Rule 9, Phase 4, and calibration rules now state: preserving a fact includes its strength.

Also observed

• Few-shot pull varies by harness: bridged Claude reproduced the approved pair nearly verbatim; codex/goose wrote fresh convergent copy. Both fine; teams should know.
• The control put "the shop" (an everyday phrase from vocabulary.md) inside copy — live evidence for the deliverable fence, triggered exactly when the system wasn't consulted.

Still open on this issue

• Setup-protocol parity (the original ask): interview order, phase fidelity, frontmatter fidelity per harness. The Larkspur persona sheet from Dry-run: Meridian setup end-to-end #2 is reusable for it.
• Per-variable isolation (same model across harnesses, or same harness across models).
• Codex/goose bridging conventions beyond CLAUDE.md (e.g., harnesses that read neither file).

Artifacts (outputs, clones, fixture provenance) preserved in the maintainer's local run archive.

[daveh-beep]

🤖 Follow-up: candidate fix rerun completed

I reran the exact Larkspur task against the candidate contract in PR #15.

Important honesty note: the first rerun was invalid — it cloned the upstream empty template instead of applying the candidate contract changes to the pinned Larkspur system. That result was discarded; it tested the wrong artifact. The corrected run used three fresh clones of Larkspur @ baecf3d, added the candidate CLAUDE.md bridge and fact-strength rule, and held the task fixed.

Corrected result:

• Claude Code read the system through the committed bridge and preserved the certain consequence as certain.
• Codex changed its prior "may need to pause" to "we have to suspend your borrowing."
• goose changed its prior "may need to pause" to "to avoid suspension of your borrowing privileges."
• all three kept house terms and invented no facts.

This closes the consult-path learning cycle: observed routing + modality failures → candidate contract changes → reproduction → corrected behavior. Setup-protocol parity (the original broader issue) stays open.