docs: simplify MITC4 verification and drilling scope

docs/requirements/linear-static-mitc4-shell.md

@@ -6,12 +6,11 @@
 - title: `Linear Static MITC4 Shell`
 - status: `approved`
 - owner_agent: `requirement-agent`
-- date: `2026-08-11`
+- date: `2026-08-12`
 - approval_basis: 사용자와 확정한 선형 정적 범위, `S4`/`S4R` 매핑, 6자유도 외부 계약, drilling 안정화, 자동 director 생성, 결과 및 검증 계약
 - current_product_state: `requirements-approved-not-implemented`
-- formulation_alignment: `docs/formulations/mitc4-shell-formulation.md`는 선행 draft이며 이 baseline의 6자유도 및 drilling 계약에 맞춘 후속 개정이 필요함
-- declared_reference_candidate: 사용자가 `reference/shell/`에 Abaqus `S4R` 모델을 추가했다고 `2026-08-11`에 선언함
-- reference_inventory_state: 요구조건 작성 시점의 workspace에서는 `reference/shell/`이 관찰되지 않아 exact artifact inventory는 `needs-reference-artifacts`로 유지함
+- formulation_alignment: `docs/formulations/mitc4-shell-formulation.md`는 이 baseline의 6자유도 및 고정 drilling 안정화 계약과 정렬함
+- reference_inventory_state: `reference/shell/`의 S4와 `reference/shellR/`의 S4R input/displacement CSV를 기존 경로와 이름 그대로 사용함
 
 ## Purpose
 
@@ -51,7 +50,7 @@ Formulation, Numerical Review, I/O, Reference Model, Implementation Planning 및
 - Abaqus source element type `S4`와 `S4R`의 동일한 FESA MITC4 매핑
 - 절점당 전역 자유도 `[UX, UY, UZ, URX, URY, URZ]`
 - 3개 병진과 director 접평면 회전 2개로 구성된 물리 MITC4 kernel
-- 비물리 local drilling 회전 1개에 대한 작은 scale-aware 수치 안정화
+- 비물리 local drilling 회전 1개에 대한 고정 수치 안정화
 - 막, 굽힘, 횡전단 및 이들의 coupling
 - 단일층, 균질 등방성 선형 탄성
 - element set별 일정한 양의 두께와 하나의 material을 갖는 `*SHELL SECTION`
@@ -60,7 +59,7 @@ Formulation, Numerical Review, I/O, Reference Model, Implementation Planning 및
 - DOF 1~6의 nodal `*BOUNDARY`와 nodal `*CLOAD`
 - deterministic assembly와 기존 linear-static partition/factorization/substitution lifecycle
 - HDF5 nodal displacement/reaction, shell generalized strain/resultant, in-plane stress, residual 및 energy output
-- element invariant, patch, locking, distortion, curved-shell, reference 및 physics verification
+- element invariant, patch, 현재 S4/S4R displacement reference 및 physics verification
 
 ## Out Of Scope
 
@@ -115,9 +114,9 @@ Formulation, Numerical Review, I/O, Reference Model, Implementation Planning 및
 - **FESA-REQ-LSMITC4-011** — The initial nodal director shall be a dimensionless unit vector in the positive thickness direction; scalar thickness shall remain a separate property and shall not be encoded in the director magnitude.
 - **FESA-REQ-LSMITC4-012** — The positive element normal candidate shall be derived deterministically from the source node order and midsurface covariant tangent cross product.
 - **FESA-REQ-LSMITC4-013** — At a smooth shared node, consistently oriented incident element normal candidates shall be combined by deterministic area-weighted averaging and normalized to form the common nodal director.
-- **FESA-REQ-LSMITC4-014** — Zero/near-zero normal candidates, a zero/near-zero averaged director, opposing incident orientations, and a fold sharper than the approved smooth-patch criterion shall fail model validation.
+- **FESA-REQ-LSMITC4-014** — Nonfinite or zero normal candidates, a nonfinite or zero averaged director, and opposing incident orientations shall fail model validation; this feature does not introduce a calibrated smooth-patch angle.
 - **FESA-REQ-LSMITC4-015** — A physical fold or hinge shall be represented with duplicated source nodes so each smooth shell patch owns a separate director; the solver shall not silently average a discontinuous director field.
-- **FESA-REQ-LSMITC4-016** — Element geometry validation shall reject duplicate nodes, self-intersection, nonfinite coordinates, degenerate area, and nonpositive or near-singular Jacobians at every formulation-required Gauss and tying location.
+- **FESA-REQ-LSMITC4-016** — Element geometry validation shall reject duplicate nodes, self-intersection, nonfinite coordinates, zero area, and nonpositive or nonfinite Jacobians at every formulation-required Gauss and tying location; this feature does not introduce calibrated distortion or warp thresholds.
 - **FESA-REQ-LSMITC4-017** — The solver shall support nodal `*BOUNDARY` targets resolved by source node label or node set for global DOFs 1 through 6, including existing zero and nonzero prescribed-displacement semantics.
 - **FESA-REQ-LSMITC4-018** — The solver shall support nodal `*CLOAD` forces on DOFs 1 through 3 and nodal moments on DOFs 4 through 6 after deterministic aggregation in global coordinates.
 - **FESA-REQ-LSMITC4-019** — The aggregated nodal moment component parallel to the approved nodal director shall be rejected as `unsupported-drilling-load`; a drilling-direction moment shall not be carried only by numerical stabilization.
@@ -140,10 +139,10 @@ Formulation, Numerical Review, I/O, Reference Model, Implementation Planning 및
 
 - **FESA-REQ-LSMITC4-031** — The physical MITC4 kernel shall use three translations and two director-tangent rotations per node and shall not treat the drilling rotation as a physical strain variable.
 - **FESA-REQ-LSMITC4-032** — The six-DOF element embedding shall transform global nodal rotations into two director-tangent components and one director-parallel drilling component using deterministic right-handed orthonormal frames.
-- **FESA-REQ-LSMITC4-033** — The drilling contribution shall be symmetric, positive, scale-aware, sufficiently small to remain numerical, and sufficient to remove the nonphysical drilling null modes of otherwise valid models.
-- **FESA-REQ-LSMITC4-034** — The drilling scale shall be derived from dimensionally compatible physical rotational stiffness; the implementation shall not apply `10^-3 * min(all Kii)` across mixed translational and rotational diagonal entries without an approved dimensional derivation.
-- **FESA-REQ-LSMITC4-035** — Drilling stabilization shall not contribute to physical membrane, bending or transverse-shear generalized strain/resultant or section-point stress; its energy shall be recovered separately.
-- **FESA-REQ-LSMITC4-036** — Exact drilling reference scale, dimensionless coefficient and acceptable artificial-energy ratio shall be approved through Research and Numerical Review before Implementation Planning; no implementation-selected default may close this decision silently.
+- **FESA-REQ-LSMITC4-033** — The drilling contribution shall be a symmetric positive numerical stabilization of the four director-parallel coordinates and shall not define a physical drilling strain or load channel.
+- **FESA-REQ-LSMITC4-034** — Let `R+` be the finite strictly positive diagonal entries of the physical local stiffness belonging only to the eight director-tangent rotational DOFs. The element shall use `k_ref=min(R+)`, `k_d=10^-3*k_ref`, `K_drill_local=k_d I4`, and the documented drilling transformation `T_d`; translational diagonals shall never enter `R+`.
+- **FESA-REQ-LSMITC4-035** — Drilling stabilization shall not contribute to physical membrane, bending or transverse-shear generalized strain/resultant, section-point stress, or separately reported result quantities.
+- **FESA-REQ-LSMITC4-036** — An otherwise accepted element with no finite strictly positive entry in `R+` shall fail numerical validation deterministically; coefficient sweeps, plateau selection, conditioning calibration, artificial-energy ratios, and drilling-specific result datasets are outside this feature.
 - **FESA-REQ-LSMITC4-037** — Source `S4R` shall not select reduced integration or Abaqus hourglass control; all accepted `S4` and `S4R` inputs shall use the single quadrature and MITC tying contract approved by the FESA formulation.
 - **FESA-REQ-LSMITC4-038** — The stabilized element shall retain exactly six physical rigid-body modes within the approved normalized tolerance, preserve stiffness symmetry and coordinate-transformation energy, and have positive energy for every accepted non-rigid physical deformation mode.
 
@@ -156,7 +155,7 @@ Formulation, Numerical Review, I/O, Reference Model, Implementation Planning 및
 - **FESA-REQ-LSMITC4-043** — The same shell locations shall output local section resultant components `[N11,N22,N12,M11,M22,M12,Q13,Q23]`, where `N` and `Q` have dimension `force/length` and `M` has dimension `force` as moment resultant per unit edge length.
 - **FESA-REQ-LSMITC4-044** — Each required shell location shall output local in-plane stress `[S11,S22,S12]` at bottom, middle and top section positions with dimension `force/length^2`; `S33` shall be documented as the plane-stress assumption and `S13/S23` point stress shall not be emitted.
 - **FESA-REQ-LSMITC4-045** — Result rows shall identify source element, integration/tying or recovery location, natural coordinates, section position, local frame/director and component order without averaging mismatched locations.
-- **FESA-REQ-LSMITC4-046** — The output shall include free-DOF residual evidence, total force/moment equilibrium metrics, physical strain energy and drilling stabilization energy with dimension `force*length` and deterministic aggregation order.
+- **FESA-REQ-LSMITC4-046** — The output shall include free-DOF residual evidence, total force/moment equilibrium metrics and physical shell strain energy with dimension `force*length` and deterministic aggregation order; no drilling-specific stiffness, ratio or energy dataset is required.
 - **FESA-REQ-LSMITC4-047** — Abaqus output requests shall neither suppress nor expand the mandatory HDF5 quantity inventory; any deterministic FESA CSV projection shall remain a debugging/review view rather than official solver output.
 - **FESA-REQ-LSMITC4-048** — Nonfinite recovery values, inconsistent component/location inventory or failure to finalize required HDF5 rows shall fail the analysis without committing a partial successful state.
 
@@ -166,10 +165,10 @@ Formulation, Numerical Review, I/O, Reference Model, Implementation Planning 및
 - **FESA-REQ-LSMITC4-050** — Element invariant tests shall cover frame orthonormality/handedness, Jacobian sign, stiffness symmetry, coordinate-transformation energy invariance, six physical rigid modes, deformation-mode positivity and deterministic repeatability.
 - **FESA-REQ-LSMITC4-051** — Normalized algebraic acceptance shall use `1e-12` for symmetry, frame orthonormality and transformation-energy invariance and `1e-10` for rigid-mode action, linear-system residual and global equilibrium unless Numerical Review approves and documents an evidence-backed scale-aware replacement before Implementation Planning.
 - **FESA-REQ-LSMITC4-052** — Patch verification shall independently cover constant membrane strain/stress, pure bending, transverse shear and twist, including sign and component-order checks for generalized strain, resultant and recovered in-plane stress.
-- **FESA-REQ-LSMITC4-053** — Locking/convergence verification shall include thin- and thick-shell or plate sequences over documented thickness ratios and mesh refinements and shall demonstrate the approved MITC4 transverse-shear behavior rather than judge one displacement on one mesh.
-- **FESA-REQ-LSMITC4-054** — Geometry verification shall include planar, smoothly curved, distorted and warped valid elements plus negative tests for degenerate, inverted, self-intersecting, opposing-normal and sharp-fold topologies.
-- **FESA-REQ-LSMITC4-055** — Curved-shell verification shall include at least one nodal-load-compatible pinched-cylinder, hemispherical-shell or equivalently justified benchmark; Scordelis-Lo may be included only with documented equivalent nodal loading inside the approved input subset.
-- **FESA-REQ-LSMITC4-056** — Drilling verification shall vary the approved stabilization coefficient around its nominal value, confirm stable equation rank, report physical displacement/resultant sensitivity and enforce the approved drilling-to-physical energy warning criterion.
+- **FESA-REQ-LSMITC4-053** — The implementation shall pass the formulation-defined element invariants and patch/manufactured tests plus the two declared S4/S4R displacement reference cases; an expanded locking, distortion or curved-shell benchmark portfolio is not an implementation-completion gate for this feature.
+- **FESA-REQ-LSMITC4-054** — Geometry validation tests shall cover the exact accepted/rejected conditions defined by the formulation and I/O contract; `NR-O03` smooth-director calibration and `NR-O04` distortion/warp threshold sweeps are not required tests.
+- **FESA-REQ-LSMITC4-055** — Additional pinched-cylinder, hemispherical-shell, Scordelis-Lo or mesh-convergence studies may be added later as nonblocking research or release evidence, but are not required for Implementation Planning or feature completion.
+- **FESA-REQ-LSMITC4-056** — Drilling verification shall check the fixed formula in Requirement 034, symmetry, positivity, deterministic assembly, removal of the four nonphysical local drilling null modes, and exclusion from physical recovery; coefficient sweeps and drilling-energy checks are not required.
 - **FESA-REQ-LSMITC4-057** — Physics verification shall check load/reaction balance, global moment balance, displacement direction, symmetry, energy positivity, result sign and consistency between assembled residual and recovered shell resultants.
 
 ## Verification Quantities
@@ -180,31 +179,29 @@ Formulation, Numerical Review, I/O, Reference Model, Implementation Planning 및
 - shell_section_resultant: required, local `N/M/Q` eight components at documented locations
 - stress: required, local bottom/middle/top `[S11,S22,S12]`; Abaqus equality comparison N/A
 - residual: required, free-DOF and normalized global equilibrium evidence
-- energy: required, separate physical strain and drilling stabilization energies
+- energy: required for the physical shell strain energy; drilling-specific energy output is not required
 - modes_and_invariants: required, six physical rigid modes, symmetry, transformation invariance and positive deformation energy
 
 ## Tolerance Policy
 
-- **FESA-REQ-LSMITC4-058** — Abaqus reference pass/fail shall apply only to matched global `U1/U2/U3` rows using `tolerance_c = absolute_floor_c + relative_coefficient_c * reference_scale_c`.
+- **FESA-REQ-LSMITC4-058** — Abaqus reference pass/fail shall apply only to matched global `U1/U2/U3` rows using `tolerance_c = 1e-9 + 1e-6 * reference_scale_c`, exactly reusing the approved B33 displacement rule.
 - **FESA-REQ-LSMITC4-059** — `reference_scale_c` shall be computed only from finite Abaqus values in the same model, step/frame, quantity and component group; reference values shall not be zero-clamped and row-specific relative denominators shall not replace the group scale.
-- **FESA-REQ-LSMITC4-060** — MITC4 displacement absolute floors and relative coefficients shall not silently inherit the B33 numerical values; Reference Model shall propose dimensioned floors and coefficients from benchmark evidence and Numerical Review shall approve them before reference comparison implementation.
-- **FESA-REQ-LSMITC4-061** — Global `UR1/UR2/UR3` rows shall be compared and fully reported but shall not affect pass/fail; errors beyond the approved large-error threshold shall emit deterministic nonblocking warnings and remain visible in known limitations.
-- **FESA-REQ-LSMITC4-062** — The UR large-error threshold and drilling-energy warning ratio are `needs-downstream-decision` owned jointly by Reference Model and Numerical Review and shall be fixed before Implementation Planning.
+- **FESA-REQ-LSMITC4-060** — The `1e-9` absolute floor is expressed in the model's user-consistent length unit for U; no additional MITC4 tolerance calibration is required.
+- **FESA-REQ-LSMITC4-061** — Global `UR1/UR2/UR3` rows shall use the same component-scale formula as Requirement 058 and shall be fully reported; an exceedance emits a deterministic nonblocking warning and never changes pass/fail.
+- **FESA-REQ-LSMITC4-062** — The `1e-9` UR floor is dimensionless. No separate UR large-error or drilling-energy threshold is required.
 - **FESA-REQ-LSMITC4-063** — Missing, extra, duplicate, nonfinite, schema-mismatched or source-identity-mismatched rows shall fail artifact/schema validation before numeric tolerance evaluation for both U and UR inventories.
 - **FESA-REQ-LSMITC4-064** — The comparison report shall record each U/UR row decision, maximum absolute error, component-scale normalized error, RMS error, vector-norm error and worst source row/component; nonblocking UR warnings shall not be omitted from an otherwise passing report.
 
 ## Reference Artifact Requirements
 
-The user-declared first candidate is `reference/shell/` and is said to contain an Abaqus
-`S4R` model. At requirements-authoring time that directory was not visible in the shared
-workspace, so no exact filename, schema, units, generator, step/frame or row inventory is
-asserted here. The bundle shall remain read-only when it becomes observable.
+The approved lightweight inventory uses the existing S4 and S4R paths below. These files
+remain read-only; their names are identities, not canonical/legacy-policy decisions.
 
-- **FESA-REQ-LSMITC4-065** — Reference Model shall inventory `reference/shell/` without creating, renaming, rewriting or repairing files and shall classify a missing/unobservable candidate as `needs-reference-artifacts` rather than fabricate its content.
-- **FESA-REQ-LSMITC4-066** — A usable new reference bundle shall contain `model.inp` and `<model-id>_displacements.csv`, or shall receive an explicitly approved legacy-alias contract that records its exact existing filenames without rename; `metadata.json` is optional and its absence shall not make the bundle unusable.
-- **FESA-REQ-LSMITC4-067** — The approved Reference Model Contract shall record Abaqus generator/version, creation provenance, source element type, model/step/frame identity, user unit system, global coordinate convention, section/material/thickness data, CSV schema and tolerance policy; if `metadata.json` exists, it shall be inventoried read-only and checked against that contract and the stored artifacts.
-- **FESA-REQ-LSMITC4-068** — Artifact validation shall confirm an approved single `*STEP, *STATIC` model, expected `S4` or `S4R` source type, supported keyword subset, unique finite displacement rows and exact source-node/component identity before comparison.
-- **FESA-REQ-LSMITC4-069** — End-to-end mapping evidence shall cover at least one `S4` input and at least one `S4R` input; the declared `reference/shell/` S4R model may satisfy only the S4R side after inventory validation, so separate S4 evidence remains required.
+- **FESA-REQ-LSMITC4-065** — The S4 case shall use `reference/shell/shell.inp` and `reference/shell/shell displacements.csv` without creating, renaming, rewriting or repairing either file.
+- **FESA-REQ-LSMITC4-066** — The S4R case shall use `reference/shellR/shellR.inp` and `reference/shellR/shellR displacements.csv` without creating, renaming, rewriting or repairing either file.
+- **FESA-REQ-LSMITC4-067** — Reference readiness requires only the declared input and required displacement CSV, FESA `results.h5`, deterministic source-node/component mapping, and Requirements 058-063 tolerance/precheck rules. README, `metadata.json`, canonical naming, provenance, Abaqus version, duplicated model semantics, and a schema version are not required gates; a present `metadata.json` is optional read-only context.
+- **FESA-REQ-LSMITC4-068** — Artifact validation shall require unique finite displacement rows and deterministic source-node/component identity before comparison; it shall not attempt to establish Abaqus internal formulation equivalence.
+- **FESA-REQ-LSMITC4-069** — The two declared cases satisfy the required source-label coverage: `reference/shell/` covers S4 and `reference/shellR/` covers S4R. No expanded reference portfolio is required for this feature.
 - **FESA-REQ-LSMITC4-070** — Reference verification shall compare FESA HDF5 global nodal displacement rows directly against Abaqus displacement CSV rows by model, step/frame, source node and component identity; a FESA-generated CSV view shall not become the authoritative comparison source.
 - **FESA-REQ-LSMITC4-071** — Abaqus reaction, stress, strain and shell force/moment output may be retained as review evidence if present but shall not change the approved `U1/U2/U3` pass/fail boundary or become an undeclared equality gate.
 - **FESA-REQ-LSMITC4-072** — FESA agents shall not execute Abaqus or another reference solver and shall not generate, modify, restore or normalize reference artifacts during requirements, research, formulation, implementation or verification unless a later phase explicitly authorizes that operation.
@@ -221,72 +218,61 @@ without gaps or overlap.
 | `002-004` | `S4`/`S4R` mapping and identity | input/model | User approval | must | Parser/semantic/HDF5 metadata tests | Both source types map to one MITC4 path and preserve distinct source metadata and four-node identity | Exact element/type identity | I/O Definition; Implementation Planning | approved |
 | `005` | Six global nodal DOFs | model | User approval; project DOF convention | must | DofManager and HDF5 schema tests | Exact component order and no distributed equation ownership | Exact ordering | Formulation; I/O Definition; Implementation Planning | approved |
 | `006-010` | Isotropic material and single-layer section | input/model | User approval | must | Parser, mapping and validation tests | Valid `E,nu,t` resolve once per element; excluded section/material meanings fail | Exact inequalities; finite values | Research; I/O Definition; Implementation Planning | approved |
-| `011-016` | Initial director and geometry validity | geometry | User approval; MITC director kinematics | must | Geometry/unit/property-based tests | Deterministic unit directors for smooth valid meshes; every invalid topology fails | Smooth-angle and scale-aware Jacobian thresholds: Research + Numerical Review | Research; Formulation; Numerical Review; I/O Definition | approved-with-downstream-decision |
-| `017-020` | Boundary and nodal-load subset | input/load | User approval | must | Parser/semantic/load tests | Global BC/CLOAD works; director-parallel moment and distributed loads fail | Drilling projection threshold: Numerical Review + I/O Definition | Formulation; I/O Definition; Implementation Planning | approved-with-downstream-decision |
+| `011-016` | Initial director and geometry validity | geometry | User approval; MITC director kinematics | must | Geometry/unit/property-based tests | Deterministic unit directors for supported valid meshes; explicitly invalid mappings fail | Exact formulation/I/O predicates; no `NR-O03`/`NR-O04` calibration gate | Formulation; I/O Definition; Implementation Planning | approved |
+| `017-020` | Boundary and nodal-load subset | input/load | User approval | must | Parser/semantic/load tests | Global BC/CLOAD works; director-parallel moment and distributed loads fail | Exact-zero/projection rule from Formulation and I/O | Formulation; I/O Definition; Implementation Planning | approved |
 | `021-023` | Parser subset, wrappers and no-op policy | input | User approval; ADR-003/013/018 | must | Parser diagnostic and semantic identity tests | Only approved meanings affect Domain; excluded meanings fail closed | Exact keyword/diagnostic inventory | I/O Definition; Implementation Planning | approved |
 | `024-030` | Ownership, deterministic assembly and linear-static execution | architecture/execution | PRD; ADR-004/007/008/009/016/017 | must | Unit, orchestration and repeated-thread-count tests | Ownership boundaries, event order, residual reaction and deterministic bytes/rows match | `1e-12` deterministic numeric target where applicable | Numerical Review; Implementation Planning | approved |
-| `031-038` | 5-DOF physics embedded in 6-DOF with drilling stabilization | numerical boundary | User approval; MITC literature and thesis 6-DOF discussion | must | Formulation review, element invariant, rank and energy tests | Physical outputs exclude drilling; stable system retains six physical rigid modes | Scale/coefficient/energy ratio: Research + Numerical Review | Research; Formulation; Numerical Review | approved-with-downstream-decision |
+| `031-038` | 5-DOF physics embedded in 6-DOF with fixed drilling stabilization | numerical boundary | User approval; MITC literature and thesis 6-DOF discussion | must | Formulation review, invariant and rank tests | Exact `10^-3` positive rotational-diagonal rule; physical outputs exclude drilling | Fixed by Requirements 033-036 | Formulation; Numerical Review; Implementation Planning | approved |
 | `039-048` | Mandatory HDF5 output and failure atomicity | output | User approval; ADR-005/016/018 | must | Recovery, schema, identity, nonfinite and atomicity tests | Every quantity/location/unit/identity exists; failure commits no partial success | Exact component/location inventory; I/O Definition owns schema | Formulation; I/O Definition; Implementation Planning | approved |
-| `049-057` | TDD, invariants, patch, locking, geometry, curved shell and physics | verification | User approval; shell benchmark evidence; project process | must | CTest evidence, analytical/patch/convergence reports and physics review | Every verification family has passing evidence before release | `1e-12` symmetry/frame; `1e-10` rigid/residual; convergence targets by Numerical Review | Research; Numerical Review; Reference Model; Implementation Planning | approved-with-downstream-decision |
-| `058-060` | Translational displacement pass/fail tolerance | tolerance | User approval | must | Comparator unit/integration tests and report review | Every matched U row uses the approved mixed tolerance without clamp/omission | Floors/coefficient: Reference Model + Numerical Review | Reference Model; Reference Verification | approved-with-downstream-decision |
-| `061-062` | Rotational warning and drilling-energy warning | tolerance/warning | User approval | must | Comparator/diagnostic tests and report review | UR never changes pass/fail; large error and energy ratio produce deterministic visible warnings | Thresholds: Reference Model + Numerical Review | Numerical Review; Reference Model; Reference Verification | approved-with-downstream-decision |
+| `049-057` | TDD, invariants, patch, declared references and physics | verification | User approval; shell formulation evidence; project process | must | CTest evidence, analytical/patch tests, two reference cases and physics review | Required tests pass; removed calibration/portfolio checks are not reintroduced | `1e-12` symmetry/frame; `1e-10` rigid/residual | Numerical Review; Implementation Planning | approved |
+| `058-060` | Translational displacement pass/fail tolerance | tolerance | User approval; B33 baseline | must | Comparator unit/integration tests and report review | Every matched U row uses `1e-9 + 1e-6*reference_scale_c` without clamp/omission | Fixed by Requirements 058-060 | Reference Verification | approved |
+| `061-062` | Rotational warning-only comparison | tolerance/warning | User approval; B33 baseline | must | Comparator/diagnostic tests and report review | UR never changes pass/fail; same mixed-tolerance exceedance emits a deterministic warning | Fixed by Requirements 061-062 | Reference Verification | approved |
 | `063-064` | Row/schema failure and report completeness | reference verification | User approval; ADR-005/014/018 | must | Negative comparator and report-schema tests | Invalid inventory fails before numeric comparison; all U/UR metrics remain visible | No ignored invalid rows | I/O Definition; Reference Verification | approved |
-| `065-068` | `reference/shell` inventory and artifact validity | reference | User declaration; project artifact policy | must | Read-only inventory and schema/provenance review | Candidate becomes usable only after exact files, S4R type, provenance and row schema are validated | Current state `needs-reference-artifacts` | Reference Model | needs-reference-artifacts |
-| `069-071` | S4/S4R coverage and displacement-only comparison | reference | User approval | must | Portfolio coverage and HDF5-to-CSV comparison | At least one model per source type; only U is blocking and UR is warning-only | Requirements `058-064` | Reference Model; Reference Verification; Physics Evaluation | approved-with-downstream-decision |
+| `065-068` | Exact S4/S4R reference-case inventory and row validity | reference | User declaration; ADR-019 | must | Read-only inventory and source-row/component precheck | Four declared paths exist; required rows are unique, finite and deterministically mapped | Requirements `058-063` | Reference Model; Reference Verification | approved |
+| `069-071` | S4/S4R coverage and displacement-only comparison | reference | User approval | must | HDF5-to-CSV comparison | Declared S4/S4R cases; only U blocks and UR only warns | Requirements `058-064` | Reference Verification; Physics Evaluation | approved |
 | `072` | Reference solver/artifact immutability | governance | User/project policy; ADR-010 | must | Process audit and Git diff | No unapproved execution or artifact mutation | Exact zero mutations | All downstream agents | approved |
 
 ## Open Questions and Required Downstream Decisions
 
-No additional user scope decision is pending. The following technical values must remain visible
-and be approved by their named downstream owners before Implementation Planning:
-
-1. Research and Numerical Review shall define a dimensionally consistent drilling reference stiffness, dimensionless coefficient range and nominal value.
-2. Numerical Review shall approve the maximum drilling-to-physical strain-energy warning ratio and the displacement/resultant sensitivity criterion for coefficient variation.
-3. Research and Numerical Review shall define the smooth-patch director angle criterion and scale-aware degenerate/Jacobian thresholds without an arbitrary `max(1, ...)` clamp.
-4. Reference Model and Numerical Review shall define MITC4 U component absolute floors and relative coefficients in the approved mixed-tolerance form.
-5. Reference Model and Numerical Review shall define the nonblocking UR large-error threshold and reporting severity.
-6. Formulation shall fix quadrature, tying-point interpolation, shear correction, local axes, sign conventions and recovery locations consistent with this baseline.
-7. `reference/shell/` shall be re-inventoried when visible. Until then its exact filenames, units, provenance and CSV schema are not established evidence.
-8. Separate `S4` end-to-end evidence remains required even if the declared `S4R` candidate is valid.
-9. The existing formulation draft's 5-DOF-only and no-drilling statements conflict with this approved baseline and shall be revised during the Formulation gate, not patched silently during implementation.
+No user or numerical calibration decision remains before Implementation Planning. Formulation
+shall retain exact quadrature, tying interpolation, local-axis, sign and recovery definitions.
+Future geometric-nonlinear execution remains separately unauthorized even though its residual
+and tangent derivation may remain in the formulation document.
 
 ## Downstream Handoff
 
 ### Research Agent
 
 - Establish source-backed MITC4 linear kinematics, tying, quadrature, shear correction and benchmark applicability.
-- Research dimensionally consistent 6-DOF drilling stabilization alternatives and sensitivity/energy criteria; distinguish the thesis's printed `10^-3 min(Kii)` rule from a FESA-approved scale-aware rule.
-- Research nodal-director generation, smooth-patch angle handling and distorted/warped geometry limits.
-- Identify nodal-load-compatible flat, locking, distorted and curved-shell benchmark families.
+- Record the thesis drilling rule and the approved dimensional restriction to positive physical rotational diagonals; do not reopen coefficient calibration.
+- Preserve nodal-director and geometry evidence as implementation guidance without creating `NR-O03`/`NR-O04` calibration gates.
 
 ### Formulation Agent
 
 - Revise `docs/formulations/mitc4-shell-formulation.md` to align with global 6-DOF input/output and a physical 5-DOF MITC4 kernel plus numerical drilling embedding.
 - Keep current-product equations strictly linear static; retain geometric-nonlinear residual/tangent only as clearly separated future formulation.
-- Define local frames, transformations, generalized component order, quadrature/tying, stress/resultant recovery, energy split and consistent units/signs.
+- Define local frames, transformations, generalized component order, quadrature/tying, stress/resultant recovery and consistent units/signs.
 - Do not introduce distributed-load product support or make `S4R` select reduced integration.
 
 ### Numerical Review Agent
 
-- Independently review the revised formulation for rigid modes, rank, symmetry, invariance, locking, distortion, Jacobian/director validation and drilling contamination.
-- Approve every downstream numerical threshold listed above before Implementation Planning.
-- Require coefficient sensitivity and artificial-energy evidence rather than accepting a small coefficient by assertion.
+- Independently review the revised formulation for dimensions, rigid modes, rank, symmetry, invariance, Jacobian/director handling and separation of fixed drilling stabilization from physical recovery.
+- Treat drilling calibration/energy-ratio checks and `NR-O03`/`NR-O04` as removed scope, not missing evidence.
 
 ### I/O Definition Agent
 
 - Define the exact Abaqus keyword/data subset for `S4`, `S4R`, single-layer `*SHELL SECTION`, material, BC and CLOAD semantics.
-- Define source identity, auto-director metadata, unsupported-drilling-load projection, diagnostics and exact HDF5 dataset/row schemas.
+- Define source identity, auto-director data, unsupported-drilling-load projection, diagnostics and exact HDF5 dataset/row schemas without drilling-specific result datasets.
 - Preserve source element type separately from FESA formulation and define bottom/middle/top stress location identity.
 
 ### Reference Model Agent
 
-- Re-inventory the user-declared `reference/shell/` candidate read-only and report exact files, S4R identity, provenance, units, step/frame and CSV row schema or `needs-reference-artifacts`.
-- Do not rename or repair noncanonical files; propose an explicit legacy alias only if retaining them is justified.
-- Prepare coverage for both S4 and S4R, flat/thin/thick/distorted/curved response and the approved displacement-only blocking comparison.
-- Propose evidence-backed U tolerance coefficients/floors and UR warning thresholds for Numerical Review approval.
+- Record the exact existing S4 and S4R input/displacement CSV paths from Requirements 065-066 and keep them read-only.
+- Define only the HDF5-to-CSV source-node/component projection and the already approved B33 mixed tolerance; do not add bundle administration or portfolio gates.
 
 ### Implementation Planning Agent
 
-- Do not start until Research, revised Formulation, Numerical Review, I/O and Reference Model contracts have resolved every named downstream decision.
+- Do not start until Research, revised Formulation, Numerical Review, I/O and lightweight Reference Model inventory are mutually consistent.
 - Trace every `must` requirement to RED/GREEN/VERIFY tests and preserve current solver ownership, deterministic assembly and failure-atomic HDF5 boundaries.
-- Include independent tests for source-type mapping, auto directors, drilling rank/energy/sensitivity, all recovery quantities, schema failures and U-versus-UR comparison behavior.
+- Use the project Harness skill to propose self-contained implementation Steps for user approval, then write only the approved phase-planning files; do not execute Harness without a separate explicit request.
+- Include tests for source-type mapping, auto directors, fixed drilling rank/separation, required recovery quantities, row failures and U-versus-UR comparison behavior; exclude coefficient sweeps, drilling energy and `NR-O03`/`NR-O04`.