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Research decisions

Every design claim on this site carries a decision id. The improver/ prompts cite them too. The papers behind each source and the Harness² prompts are in research provenance.

# Decision in the v2 spec Evidence Source
D1 No proposal without an execution trace Editing the harness directly, without reference executions or probes, degraded performance: WB-code 73.4 → 63.2, WB-web 69.9 → 65.0 Harness² §4, Fig. 7 left
D2 Skills and scripts first; hooks and prompts last (lint form order) Removing skills from the improved harness cost 5.3 points, scripts 3.7, all prompt text 1.5 (Gemini 3.5 Flash, OpenCode, k=5). Skills and scripts were ~half of all edits Harness² Table 6, Fig. 10
D3 All eight surfaces editable Harness² exposes system prompt, guardrails, memory, tool guidance, subagents, skills, scripts, plugin; AHE’s seven file-typed components; the plugin/hook slot is “the only lever that can enforce something the model cannot skip” Harness² §2.1, Table 5; AHE
D4 Compiled hooks for recurring corrections, not prose The same user-correction rules in context: 55.0% compliance; compiled into applicability check + instruction + verifier hooks: 70.1% Trace (arXiv 2606.13174)
D5 One scoped editor in interactive mode; invariant vs domain scope Scoping ablation was Harness²’s largest: without it −2.9 (WorkBuddy) and −3.7 (JobBench) Harness² Table 3
D6 Composer only in batch mode, where probes exist Composition ablation −1.6/−1.9; but a composer choosing between untested texts is blind selection, and blind selection produced Harness²’s worst regressions (−41, −30, −28) Harness² Table 3, Fig. 14; reviewer finding 4
D7 Verifier picks in batch mode; no LLM selector Three of nine Harness² regressions were the selector choosing a worse candidate (55 over 95, 70 over 100, 26 over 54) Harness² Fig. 14
D8 Provisional by default; “kept”, never “verified” Edits written by a frontier model without validation were net negative: 21 of 39 valid patches lowered batch success; an untrained Gemini editor reduced ALFWorld 41.6 → 35.4 Harness-R1 (arXiv 2608.02276)
D9 Failure-only reflection; no self-judged positives Self-generated feedback scored 27.96/61.67, below no-evolution, in Evo-Harness; sparse pass/fail feedback (67.33) ≈ verbose (67.00) Evo-Harness (arXiv 2608.15071)
D10 Counters measure recurrence of the motivating redirect class Free signals vary tenfold by task (tokens, errors); recurrence of a specific redirect is the one signal that is specific and hard to fake; user corrections define misalignment in the 20k-session study Reviewer finding 7; How Coding Agents Fail Their Users (arXiv 2605.29442)
D11 No on/off withholding arm in Phase 1 Withholding a fix the user asked for both harms them and inflates the comparison; and pi’s before_agent_start cannot hide one skill Reviewer findings 1, 8 (verified against pi 0.80.9 docs/extensions.md)
D12 Deterministic trigger predicate per entry Counters are meaningless unless “matched” is computed identically for every session Reviewer finding 2
D13 Caps forcing merges; retirement; archive never delete Every unbounded library peaked then declined: Recuris added 51 skills, retired 0, kept 17 near-duplicates; Adaptive Auto-Harness prompt 2 KB → 68 KB then decline; Evo-Harness caps 5 general + 5 per topic Recuris (2608.24876); Adaptive Auto-Harness (2606.01770); Evo-Harness
D14 Append itemized units with counters; never let a model rewrite the library Dynamic Cheatsheet’s monolithic rewrite collapsed 18,282 tokens @ 66.7 to 122 tokens @ 57.1, below the 63.7 baseline ACE (arXiv 2510.04618)
D15 Lint: no task ids, no string-match branches, applicability clause required HarnessCompass’s generalization gate: seed 51.8 → 61.0 total with held-out 51.6 → 60.4, vs AHE 55.5 in 20 turns; gate alone 58.8 in 2 turns HarnessCompass (arXiv 2608.01918)
D16 Per-edit manifest with predicted fixes and predicted regressions AHE’s change manifests, scored next round; fix precision/recall 33.7%/51.4% vs regression 11.8%/11.1% shows regression blindness is the risk AHE (arXiv 2604.25850)
D17 Batch winners provisional until the next real run passes Single-rollout acceptance has no noise floor; an unchanged harness scored 43.4–55.4 across 10 runs on ARC-AGI-3; Recuris measured a 25.9% A/A flip floor arXiv 2610.30499; Recuris
D18 Kill criterion for the project; no benchmark harness as prerequisite 54% of reported harness gains were overfitting and validation did not prevent it; offline evolution generalized +0.0 on disjoint TB2.1 splits Harness-Delta Attribution (2610.22466); Wang et al. (2607.12227)
D19 Expect low single digits for strong models, more for weak ones Deployed-static evidence: library without probing +0.9/+4.4/+5.1; cross-benchmark transfer +0.5 to +2.9; GLM-5 gained 17.3 from a transferred harness, Opus 4.8 +2.6/+1.1 Harness² Fig. 7, Fig. 12
D20 Record model family, don’t gate on it; editor = strongest configured Same-model editing worked for all five models tested (Opus 5 +3.3/+5.5/+3.0); strong builder for weak target: ToM 0.488 → 0.912 Harness² Fig. 8; AI4AI (2608.12307)
D21 Scripts offload reasoning into code; track deterministic fraction Deterministic fraction vs accuracy r = 0.72; 94% of BigToM answered by code with no model call AI4AI
D22 Skill packages: short router, units, facts with as_of, harness-driven retrieval A loaded skill body costs ~50% more episode tokens; on-demand loading keeps ~51% of the gain; adding a checkable rule +0.41 compliance (2,608 SKILL.md revisions). Call-time retrieval of skills beat model-controlled invocation of the same skills 83.6 vs 65.6 (+18.0); recall tools were never invoked in 56.3% of settings when left to the model Agent Skill Evolution (2610.04832); Recuris; Fan et al. (2609.20804)
D23 Context truncation and stuck detector are entries, not always-on changes Age-based tool-output truncation + stuck detector: F2PF 28% → 49% at 20k tokens, converging at 262k; cheap rule-based elision before any LLM summarization Lewis (2608.26218); Fan et al.
D24 Trust boundary by record types; proposals carry no score; receipts need certificates Bellwether ADR 009/004/005: “the boundary is enforced by the record types, not by a prompt” bellwether docs/evolve.md, README
D25 Experience library read by editors; improver prompts not self-amended Library ablation −3.1/−1.8 (reading experience helps); a self-editing meta-level “may evolve far more rapidly than humans can audit” Harness² Table 3; Hyperagents (2603.19461); reviewer finding 18
D26 Verifiers never evolve by agent score Verifier selected without anchors collapsed to always-pass while downstream scores still rose; self-evolution without execution-based verification scored 31.79 < blank harness 33.95 Who Verifies the Verifier? (NeurIPS 2026 WS); VERSE (2610.02616)
D27 Redirect classification needs recurrence thresholds DSAT detection agreed with humans at κ = 0.50; 42% of invalid misalignment extractions were “normative prior bias”; users leave text feedback ~2× more when dissatisfied WildFeedback (2408.15549); How Coding Agents Fail Their Users
D28 Session outcome records with exact signature, MinHash, facets Research-log of tested hypotheses prevents retesting; “stop at 6 queries” overfit (95% one batch, 15% next) Adaptive Auto-Harness