core/docs/decisions/ADR-0087-rhetorical-style-axis.md

ADR-0087 — Rhetorical Style as Selection Axis (Pre-Work for Writing Curriculum)

Status: Proposed Date: 2026-05-20 Author: Shay

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Context

A writing-curriculum extension to CORE is being scoped (informal name: "PhD-level reading/writing"). Before any composer, content, or eval-lane work begins, one architectural decision must be pinned: what kind of mechanism is rhetorical style?

Two answers are plausible:

1. A motor. Style is encoded as a versor applied to the field at compose time. A "scientific" style is a different operator than a "popular" style; the operator transforms the realized state before surface emission.
2. A selection axis. Style is encoded as a pack the operator mounts at configuration time. A "scientific" deployment loads one pack; a "popular" deployment loads another. The realizer does not change behavior at compose time; it draws from a different substrate.

These look superficially similar — both can produce different surfaces for the same prompt. They are not similar at all structurally. The choice we make here propagates into every downstream design decision in the writing curriculum.

Why this is the right moment to decide

Two prior results constrain the answer:

• The φ-separation result (memory: phi-separation-falsified) established that semantic capability lives in chain composition, not in φ geometry. By extension, style capability — to the extent it is rhetorical-mode selection rather than semantic-content change — should not require a φ change either.

• ADR-0085's "fusion operator" rejection. The proposal to fuse realized template with geometric state before lexical collapse was declined on the grounds that it re-couples the realizer to field dynamics, breaks deterministic replay in a new place, and re-imports the transformer-style coupling CORE deliberately is not. A style-as-motor design has the same anti-pattern shape.

The current decoupling — geometric field → propositional plan → deterministic realizer → realized surface → register decoration — is load-bearing. Every prior ADR that improved capability did so by expanding the substrate the realizer draws from, not by reaching into the geometry. ADR-0083 added depth (transitive chains). ADR-0084 added definitions (gloss substrate). ADR-0085 added a frame for the same substrate (gloss-aware CAUSE). None of them changed the field.

Rhetorical style should follow the same pattern.

Existing axes for context

Two selection axes are already pinned by prior ADRs:

Axis	ADR	What varies	trace_hash behavior	Engagement point
Register	ADR-0070	Surface decoration (terse / convivial / formal)	CONSTANT	post-composer (decorate_surface)
Anchor lens	ADR-0073	Semantic-vocabulary tradition (Greek philosophical / Hebrew covenant)	DISTINCT	pre-realizer (substrate composer)

These are CI-pinned as orthogonal: anchor_lens_byte_identity_null_lift holds the unanchored-vs-null identity; the register tour holds the register-vs-trace invariance; the anchor-lens tour holds the lens-vs-trace distinctness. Both invariants hold simultaneously (memory: adr-0073d-anchor-lens-telemetry-tour).

Rhetorical style needs to slot into this taxonomy without breaking either axis.

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Decision

Rhetorical style is a selection axis, not a motor. It is a third substantive axis, sibling to anchor lens, orthogonal to register.

Axis definition

Property	Value
Mechanism	Pack the operator mounts at runtime configuration time. Not a geometric operator, not a φ change, not a fusion at compose time.
What it varies	The rhetorical-mode frames the realizer is permitted to emit AND the rhetorical-move requirements the composer applies (e.g., academic style requires an evidence-bearing chain for every assertion; popular style does not).
What it does NOT vary	The semantic content (that's anchor-lens territory). The surface decoration (that's register territory). The field dynamics, versor closure, vault recall, or trace machinery (those are non-negotiable invariants).
trace_hash behavior	DISTINCT across styles. Style selection is substantive: it changes which moves the composer requires and which frames the realizer emits, which changes the propositional plan that feeds the trace. (CONTRAST with register, which holds trace constant.)
Engagement point	Pre-realizer, alongside anchor lens. The composer consults the active rhetorical-style pack when assembling the proposition graph; the realizer consults it when choosing frames.
Default	A default_unstyled_v1 pack identical in effect to the absence of styling — null-lift, byte-identical traces. Mirrors ADR-0073b's default_unanchored_v1.

Pack shape (substrate, not consumer)

Analogous to packs/anchor_lens/<id>/:

packs/rhetorical_style/<id>/
  manifest.json              — pack identity, version, mastery_report seal
  rhetorical_style.json      — the pack content (see schema below)
  <id>.mastery_report.json   — companion self-seal, verified at load

rhetorical_style.json schema (proposed v1):

{
  "pack_id": "en_academic_v1",
  "version": 1,
  "issued_at": "2026-05-21T00:00:00Z",
  "default_unstyled": false,            // true only for the no-op pack
  "permitted_frames": [                 // realizer frame allow-list
    "warrant",                          //   "Therefore X, because Y."
    "concession",                       //   "While X, Y."
    "hedge",                            //   "This suggests X, though Q."
    "definitional_move"                 //   "By X we mean {gloss}."
  ],
  "required_moves_per_claim": [         // composer must include
    "evidence",                         //   every assertion needs evidence
    "warrant"                           //   bridging the evidence-claim gap
  ],
  "forbidden_moves": [                  // moves the style refuses
    "bare_assertion"                    //   no claims without warrant
  ],
  "provenance": "adr-0087:reviewed:2026-05-21"
}

Three named frames in the v0 vocabulary (warrant, concession, hedge, definitional_move) are the minimum set the realizer needs to express the claim-evidence-warrant triad. More frames are added as the writing curriculum proves their necessity, not preemptively.

Composer & realizer contract

This ADR pins the contract; it does not implement the consumers. The consumer ADR (call it ADR-0089 in the writing sequence) will add:

• A RuntimeConfig.rhetorical_style_id: str | None = None field (default → default_unstyled_v1 per mounting discipline).
• A chat/runtime.py plumb to make the active style pack available to the composer and realizer.
• Realizer extensions that read permitted_frames and refuse to emit frames outside the allow-list.
• Composer extensions that read required_moves_per_claim and refuse to ratify a surface that omits a required move.

The substrate lands first (this ADR + pack schema + loader + default_unstyled_v1 pack). The consumer lands second after the substrate ratifies. This is the same sequencing discipline as ADR-0084 → 0085.

Forbidden alternatives

These are explicitly not the design, named here so future PRs recognize them as anti-patterns:

Anti-pattern	Why rejected
Style as motor. A versor applied to the field at compose time.	Re-couples realizer to geometry. Breaks deterministic replay (trace_hash now depends on compose-time field state). Same shape as the rejected ADR-0085 fusion proposal.
Style as register. Treating "academic" as a register-pack variant.	Conflates substantive (what moves must appear) with stylistic (how to decorate the surface). Would either bloat register packs with rhetorical-mode logic or silently broaden the trace-constant invariant.
Style as identity axis. A precision: high axis under IdentityPack.	Identity should be load-bearing and falsifiable (memory: identity-doctrine), not a place to encode per-deployment preferences. Adding "is academic style" as an identity axis is the bloat that doctrine refuses.
Style detected from user input. Auto-routing prompts to "scientific" vs "popular" lens based on heuristics.	Substantive variation should be operator-chosen, not auto-detected. The system shouldn't decide that this user "wants science"; the deployment decides what the system is.

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Verification

Required tests for the substrate

• Pack loader:
  • default_unstyled_v1 ratifies with the same mastery-report self-seal discipline as default_unanchored_v1.
  • Missing pack → RhetoricalStylePackError (fail-closed, sister to SafetyPackError).
  • permitted_frames keys validated against a known-frame allow-list.
• Schema validation:
  • Unknown keys inside the rhetorical-style block → ratification failure.
  • default_unstyled: true only valid when permitted_frames, required_moves_per_claim, and forbidden_moves are all empty.
• Null-lift invariant (CI-pinned):
  • rhetorical_style_null_lift: under rhetorical_style_id=None (resolves to default_unstyled_v1), every cognition lane case produces a byte-identical surface + trace_hash to today's no-style baseline.
• Three-axis orthogonality (CI-pinned):
  • With register + anchor lens + rhetorical style all selectable independently, the orthogonality tour must show:
    • Register varies → trace_hash CONSTANT (existing invariant).
    • Anchor lens varies → trace_hash DISTINCT (existing invariant).
    • Rhetorical style varies → trace_hash DISTINCT (new invariant).
    • All three axes vary simultaneously without breaking either style or lens axis.

Lanes (regression check)

core test --suite smoke -q
core test --suite cognition -q
core test --suite packs -q
core test --suite teaching -q
core test --suite runtime -q
core eval cognition          (byte-identical at default config)

What this ADR does NOT verify

• Realizer frame-emission correctness — that's the consumer ADR.
• required_moves_per_claim enforcement — that's the consumer ADR.
• The harvester (Layer 0 of the writing curriculum) — separate spec.
• Genre-specific gloss content for any style other than default_unstyled_v1 — separate content effort.

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Consequences

What changes

• New packs/rhetorical_style/<id>/ directory layout, sister to packs/anchor_lens/ and packs/safety/.
• New packs/rhetorical_style/loader.py with RhetoricalStylePack dataclass and ratification gates.
• New default_unstyled_v1 pack that produces the null-lift baseline.
• docs/runtime_contracts.md updated to declare rhetorical style as the third substantive axis with its trace_hash invariant.

What does not change

• Composer or realizer behavior. Substrate-only ADR; consumers are a follow-up.
• Register or anchor-lens axes. Both remain operational with their current invariants.
• Versor / vault / recall / field dynamics. Untouched.
• The non-negotiable versor_condition(F) < 1e-6 invariant.
• Identity / safety / ethics packs. Style is a fourth pack family (identity | safety | ethics | rhetorical_style), not a modification to any of them.

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Scope limits

• No consumer code. Realizer + composer integration is the next ADR's job.
• No genre packs. Only default_unstyled_v1 ships in this ADR. en_academic_v1, en_technical_v1, etc., are content efforts that follow once the substrate ratifies and the consumer ADR lands.
• No prompt-routing. Style selection is operator-set at RuntimeConfig time only. Auto-detection is explicitly out of scope.
• No retroactive renaming of anchor lens. Anchor lens stays substantive-vocabulary; rhetorical style is the substantive-frame axis. They are siblings, not subsets.
• No motor variant accepted. Future PRs proposing style-as-motor must rebut this ADR; the burden of proof is on the proposer.

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Why now

A writing curriculum is being scoped. Before any composer extension, content harvest, or eval lane lands for that curriculum, the mechanism of rhetorical style needs to be fixed in writing. Without this ADR, every downstream PR will face the same question ("should this be a motor?") and the temptation to reach for the geometry will recur every time the realizer produces a stilted surface. Pinning the axis up front prevents that recurrence.

ADR-0087 is also the smallest possible commitment: pack schema + loader + one null-lift pack + invariants. No consumer code, no content, no realizer change. It's the most reversible-yet- load-bearing step in the writing-curriculum sequence.

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Cross-References

• ADR-0070 — register axis (stylistic, trace CONSTANT). Rhetorical style is the substantive sibling.
• ADR-0073 — anchor lens axis (substantive vocabulary, trace DISTINCT). Rhetorical style adopts the same substrate-pack discipline.
• ADR-0084 — substrate-then- consumer sequencing pattern. Reused here verbatim.
• ADR-0085 — frame-swap-not-fusion precedent. The "fusion operator" rejection is the load-bearing prior art for this ADR's "motor rejection."
• Memory: phi-separation-falsified — semantic capability lives in chain composition, not φ geometry. Style capability is the natural next case of the same principle.
• Memory: identity-doctrine — why style does not belong on the identity axis.
• Future ADR-0088: rhetorical-style consumer (composer + realizer integration).
• Future ADR-0089: writing-chain harvester (Layer 0 of the writing curriculum, separately specified).
• Future spec: docs/curriculum/writing-chain-harvester-spec.md — the harvester specification this ADR's substrate ultimately serves.