docs: add phase 1 sprint contracts

PLAN.md

@@ -13,7 +13,7 @@ Every new agent session must read this file together with `PROGRESS.md` before p
 - If an item becomes obsolete, move it to `PROGRESS.md` with a short reason instead of silently deleting it.
 
 ## Current Objective
-Prepare FESA for Phase 1 implementation planning: a reference-verified linear static MITC4 shell solver using the documented architecture, numerical conventions, Abaqus input subset, HDF5 result schema, and stored reference artifacts.
+Execute the generated Phase 1 harness plan for a reference-verified linear static MITC4 shell solver using the documented architecture, numerical conventions, Abaqus input subset, HDF5 result schema, and stored reference artifacts.
 
 ## Required Reading For New Agents
 1. `AGENTS.md`
@@ -29,6 +29,14 @@ Prepare FESA for Phase 1 implementation planning: a reference-verified linear st
 11. `docs/VERIFICATION_PLAN.md`
 12. `docs/RESULTS_SCHEMA.md`
 13. `docs/MITC4_FORMULATION.md`
+14. `phases/index.json`
+15. `phases/1-linear-static-mitc4/index.json`
+
+## Active Phase Files
+- Phase directory: `phases/1-linear-static-mitc4`
+- Execute with: `python scripts/execute.py 1-linear-static-mitc4`
+- Step numbering is zero-based for the harness: `step0.md` corresponds to milestone P1-01, and `step15.md` corresponds to milestone P1-16.
+- Every step file contains a sprint contract with objective, scope, allowed files, tests-first plan, reference-artifact policy, evaluator checklist, acceptance command, and handoff requirements.
 
 ## Phase 1 Readiness Tasks
 | ID | Status | Owner | Task | Source |
@@ -79,7 +87,6 @@ All milestones are intended to become one or more self-contained sprint contract
 
 | ID | Status | Owner | Objective | Depends On | Acceptance Focus |
 |---|---|---|---|---|---|
-| P1-00 | pending | harness sprint planner | Convert this PLAN into executable phase files with sprint contracts. | R-004..R-011 status reviewed | Phase files contain objective, scope, allowed files, tests-first plan, reference artifacts, evaluator checklist |
 | P1-01 | pending | build/system generator | Establish C++ project skeleton, build system, test framework, and validation script integration. | R-008 | `python scripts/validate_workspace.py` runs build/test checks |
 | P1-02 | pending | core generator | Add core numeric/id types, DOF enum, diagnostics primitives, and logging/error result conventions. | P1-01 | Tests for int64 aliases, DOF mapping, diagnostic payloads |
 | P1-03 | pending | domain generator | Implement immutable-ish `Domain` entities: nodes, elements, sets, materials, shell properties, loads, boundaries, steps. | P1-02 | Tests for construction, lookup, duplicate ids, label preservation |

PROGRESS.md

@@ -17,6 +17,47 @@ The project is in documentation and readiness planning. Solver implementation ha
 
 ## Completed Work
 
+### 2026-05-01 - P1-00 Phase 1 sprint contracts generated
+Author: Codex
+
+Changed files:
+- `phases/index.json`
+- `phases/1-linear-static-mitc4/index.json`
+- `phases/1-linear-static-mitc4/step0.md`
+- `phases/1-linear-static-mitc4/step1.md`
+- `phases/1-linear-static-mitc4/step2.md`
+- `phases/1-linear-static-mitc4/step3.md`
+- `phases/1-linear-static-mitc4/step4.md`
+- `phases/1-linear-static-mitc4/step5.md`
+- `phases/1-linear-static-mitc4/step6.md`
+- `phases/1-linear-static-mitc4/step7.md`
+- `phases/1-linear-static-mitc4/step8.md`
+- `phases/1-linear-static-mitc4/step9.md`
+- `phases/1-linear-static-mitc4/step10.md`
+- `phases/1-linear-static-mitc4/step11.md`
+- `phases/1-linear-static-mitc4/step12.md`
+- `phases/1-linear-static-mitc4/step13.md`
+- `phases/1-linear-static-mitc4/step14.md`
+- `phases/1-linear-static-mitc4/step15.md`
+- `PLAN.md`
+- `PROGRESS.md`
+
+Summary:
+- Converted Phase 1 milestones P1-01 through P1-16 into executable Harness step files under `phases/1-linear-static-mitc4`.
+- Added top-level and phase-level JSON indices using the zero-based `scripts/execute.py` convention.
+- Embedded sprint contracts in every step with objective, required reading, scope, allowed files, explicit non-goals, tests to write first, reference-artifact policy, acceptance command, evaluator checklist, and handoff requirements.
+- Kept readiness blockers visible, especially MITC4 formulation decisions, build-system selection, reference comparator tolerance, missing reaction CSV, and the need for Phase 1-compatible `TYPE=S4` references.
+- Updated `PLAN.md` so new agents can find and execute the active phase files.
+
+Verification:
+- Parsed `phases/index.json` and `phases/1-linear-static-mitc4/index.json` with PowerShell `ConvertFrom-Json`.
+- Verified the phase registry points to `1-linear-static-mitc4`, all 16 steps are `pending`, step names are kebab-case, and every `stepN.md` file exists.
+- Verified every step file includes the required sprint contract sections from `docs/HARNESS_ENGINEERING.md`.
+- `python scripts/validate_workspace.py` exited successfully, but still reported no configured validation commands.
+
+Follow-up:
+- Begin Phase 1 execution with `python scripts/execute.py 1-linear-static-mitc4` after confirming readiness blockers are accepted, resolved, or intentionally deferred.
+
 ### 2026-05-01 - Phase 1 implementation master plan added
 Author: Codex
 

phases/1-linear-static-mitc4/index.json

@@ -0,0 +1,86 @@
+{
+  "project": "FESA",
+  "phase": "1-linear-static-mitc4",
+  "steps": [
+    {
+      "step": 0,
+      "name": "build-test-harness",
+      "status": "pending"
+    },
+    {
+      "step": 1,
+      "name": "core-types-diagnostics",
+      "status": "pending"
+    },
+    {
+      "step": 2,
+      "name": "domain-model",
+      "status": "pending"
+    },
+    {
+      "step": 3,
+      "name": "parser-foundation",
+      "status": "pending"
+    },
+    {
+      "step": 4,
+      "name": "parser-phase1-subset",
+      "status": "pending"
+    },
+    {
+      "step": 5,
+      "name": "domain-validation-diagnostics",
+      "status": "pending"
+    },
+    {
+      "step": 6,
+      "name": "analysis-model-dof-manager",
+      "status": "pending"
+    },
+    {
+      "step": 7,
+      "name": "math-solver-adapters",
+      "status": "pending"
+    },
+    {
+      "step": 8,
+      "name": "results-writer-minimal",
+      "status": "pending"
+    },
+    {
+      "step": 9,
+      "name": "reference-displacement-comparator",
+      "status": "pending"
+    },
+    {
+      "step": 10,
+      "name": "mitc4-formulation-closure",
+      "status": "pending"
+    },
+    {
+      "step": 11,
+      "name": "mitc4-element-baseline",
+      "status": "pending"
+    },
+    {
+      "step": 12,
+      "name": "assembly-reaction-recovery",
+      "status": "pending"
+    },
+    {
+      "step": 13,
+      "name": "linear-static-analysis-path",
+      "status": "pending"
+    },
+    {
+      "step": 14,
+      "name": "stored-reference-regression",
+      "status": "pending"
+    },
+    {
+      "step": 15,
+      "name": "phase1-evaluator-closeout",
+      "status": "pending"
+    }
+  ]
+}

phases/1-linear-static-mitc4/step0.md

@@ -0,0 +1,73 @@
+# Step 0: build-test-harness
+
+## Sprint Contract
+
+### Objective
+Establish the C++ project skeleton, build system, test framework, and validation script integration required before solver code begins.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/PRD.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/VERIFICATION_PLAN.md
+
+### Scope
+- Choose the Phase 1 build/test path. CMake is recommended unless project constraints require another choice.
+- Add a minimal C++17 project skeleton with one smoke-test target.
+- Wire `scripts/validate_workspace.py` to run real configured checks.
+- Document the build-system decision in ADR if it changes or becomes explicit.
+
+### Allowed Files
+- `CMakeLists.txt` or the selected build-system files
+- `src/**`
+- `include/**`
+- `tests/**`
+- `scripts/validate_workspace.py`
+- `README.md`
+- `docs/ADR.md`
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not implement solver, parser, MITC4, results, or reference-comparison behavior.
+- Do not introduce MKL, TBB, or HDF5 APIs into solver core during this setup step.
+- Do not mark readiness blockers R-004 through R-011 as solved unless this step actually resolves them.
+
+### Tests To Write First
+- A minimal C++ smoke test that fails before the test harness is connected and passes after the harness is wired.
+- A validation-script test or self-check proving `python scripts/validate_workspace.py` reports the configured build/test command status.
+
+### Reference Artifacts
+- None. This step does not use `references/*.inp` or `references/*_displacements.csv`.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- The project builds with C++17 or newer.
+- The chosen test framework runs through the validation script.
+- `scripts/validate_workspace.py` no longer reports that no checks are configured.
+- The build-system decision is documented if new or changed.
+- No solver behavior was implemented.
+
+### Handoff Requirements
+- Update `PROGRESS.md` with changed files, validation output, and any build-system caveats.
+- Update `PLAN.md` only for changed future work or resolved blockers.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Confirm the smoke test is executed by the validation script.
+3. Inspect the diff for accidental solver behavior or dependency leakage.
+
+## Do Not
+- Do not expand Phase 1 scope to make a build demo more impressive.
+- Do not commit generated build artifacts.

phases/1-linear-static-mitc4/step1.md

@@ -0,0 +1,68 @@
+# Step 1: core-types-diagnostics
+
+## Sprint Contract
+
+### Objective
+Add core numeric/id types, shell DOF enumeration, diagnostics primitives, and error-result conventions used by later layers.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /phases/1-linear-static-mitc4/step0.md
+
+### Scope
+- Define int64-based ids, indices, and equation-number types.
+- Define `double` as the default scalar precision.
+- Define the six shell DOFs in the documented order: `UX`, `UY`, `UZ`, `RX`, `RY`, `RZ`.
+- Add diagnostics/result primitives with enough context for parser, validation, and solver errors.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `docs/ADR.md`
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not add Domain, parser, DofManager, sparse matrix, or MITC4 element behavior.
+- Do not use 32-bit ids, equation numbers, or sparse indices.
+- Do not encode global equation ids inside node or element data structures.
+
+### Tests To Write First
+- Unit tests for id/index/equation type sizes and signedness expectations.
+- Unit tests for DOF ordering, component labels, and stable integer mapping.
+- Unit tests for diagnostic severity, code, message, and source-location payloads.
+
+### Reference Artifacts
+- None.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Core types are reusable without depending on parser, analysis, MKL, TBB, or HDF5.
+- DOF labels and order match `docs/NUMERICAL_CONVENTIONS.md`.
+- Diagnostics can carry actionable context for unsupported input and singular systems.
+- Tests were added before behavior and pass through validation.
+
+### Handoff Requirements
+- Record completed work and validation in `PROGRESS.md`.
+- Keep `PLAN.md` focused on future blockers only.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect tests for explicit int64 and DOF-order assertions.
+
+## Do Not
+- Do not infer future element or solver APIs beyond what this contract requires.

phases/1-linear-static-mitc4/step10.md

@@ -0,0 +1,69 @@
+# Step 10: mitc4-formulation-closure
+
+## Sprint Contract
+
+### Objective
+Close the MITC4 formulation decisions required before element implementation: transverse shear tying, local basis, integration ordering, drilling stiffness default, and Phase 1 output scope.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/PRD.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/RESULTS_SCHEMA.md
+- /docs/MITC4_FORMULATION.md
+- /docs/VERIFICATION_PLAN.md
+
+### Scope
+- Update `docs/MITC4_FORMULATION.md` with the exact baseline formulas and implementation checklist needed for coding.
+- Resolve or explicitly defer R-004, R-005, R-006, and R-007.
+- Record literature/source basis and benchmark expectations without requiring local Abaqus execution.
+- Update ADR or PLAN only when a durable design decision changes.
+
+### Allowed Files
+- `docs/MITC4_FORMULATION.md`
+- `docs/RESULTS_SCHEMA.md`
+- `docs/VERIFICATION_PLAN.md`
+- `docs/ADR.md`
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not implement C++ MITC4 code in this step.
+- Do not invent formulas from memory without documenting the source or derivation.
+- Do not expand Phase 1 outputs beyond resolved R-007.
+
+### Tests To Write First
+- No C++ tests are required unless executable formulation checks already exist.
+- Add documentation checklist items or review notes that can be evaluated before Step 11.
+
+### Reference Artifacts
+- None required. Existing `references/quad_01*` may inform future benchmark planning but is not a Phase 1 MITC4 acceptance case.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Transverse shear tying equations are explicit enough to implement.
+- Local shell basis construction is explicit for flat and non-flat quads.
+- Drilling stiffness default scale and parameter name are finalized.
+- Integration ordering and output scope are finalized or explicitly deferred with downstream blockers.
+- Step 11 remains blocked if any required formulation item is unresolved.
+
+### Handoff Requirements
+- Record closed decisions and remaining risks in `PROGRESS.md`.
+- Remove or update resolved readiness tasks in `PLAN.md`.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Review docs for implementable formulas and unresolved placeholders.
+
+## Do Not
+- Do not let implementation begin on undocumented MITC4 formulas.

phases/1-linear-static-mitc4/step11.md

@@ -0,0 +1,71 @@
+# Step 11: mitc4-element-baseline
+
+## Sprint Contract
+
+### Objective
+Implement the baseline MITC4 element utilities and stiffness path after the formulation gate is closed.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/PRD.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/MITC4_FORMULATION.md
+- /phases/1-linear-static-mitc4/step10.md
+
+### Scope
+- Implement shape functions, derivatives, local basis utilities, MITC shear tying per the finalized formulation, stiffness calculation, and drilling stiffness parameter path.
+- Keep the element behind runtime-polymorphic element interfaces.
+- Produce a 24x24 element stiffness for four-node shell elements with six DOFs per node.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `docs/MITC4_FORMULATION.md` only for errata discovered during implementation
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not implement S4R, reduced integration, hourglass control, nonlinear kinematics, pressure loads, composites, thermal coupling, or mesh quality checks.
+- Do not implement formulas that are still placeholders in `docs/MITC4_FORMULATION.md`.
+- Do not optimize element kernels before baseline benchmark behavior is established.
+
+### Tests To Write First
+- Shape function partition and nodal interpolation tests.
+- Derivative and Jacobian/local basis tests.
+- 24x24 dimension and symmetry tests.
+- Rigid body or patch-style checks appropriate to the documented formulation.
+- Drilling stiffness sensitivity tests.
+
+### Reference Artifacts
+- None required for this unit-level step. Stored-reference regression is Step 14.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Step 10 formulation decisions are closed before code is added.
+- Element interface uses runtime polymorphism as documented.
+- Stiffness output dimension, DOF order, symmetry, and drilling behavior are tested.
+- No S4R or nonlinear behavior was introduced.
+
+### Handoff Requirements
+- Record implemented formulation surface and validation in `PROGRESS.md`.
+- Update `PLAN.md` if benchmark or formulation risks remain.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect tests against the finalized MITC4 formulation checklist.
+
+## Do Not
+- Do not hide formulation uncertainty in comments or TODOs inside executable code.

phases/1-linear-static-mitc4/step12.md

@@ -0,0 +1,71 @@
+# Step 12: assembly-reaction-recovery
+
+## Sprint Contract
+
+### Objective
+Implement assembly of element stiffness/load contributions into full and reduced system data while preserving full-space data for reactions.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/RESULTS_SCHEMA.md
+- /phases/1-linear-static-mitc4/step6.md
+- /phases/1-linear-static-mitc4/step7.md
+- /phases/1-linear-static-mitc4/step11.md
+
+### Scope
+- Assemble global stiffness and load data from active elements and nodal loads.
+- Create reduced free-DOF systems using `DofManager` mappings.
+- Preserve or reconstruct full-space `K_full`, `F_full`, and `U_full` data needed for `RF = K_full * U_full - F_full`.
+- Add assembly diagnostics for missing contributions and singular-prone untouched DOFs where detectable.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not implement the full `LinearStaticAnalysis` orchestration here.
+- Do not compute reactions from reduced quantities only.
+- Do not add pressure loads, nonzero prescribed displacement, or nonlinear residual assembly.
+
+### Tests To Write First
+- Assembly tests for simple element/load contributions into full and reduced matrices/vectors.
+- Constrained elimination tests using known DOF mappings.
+- Full-vector reaction recovery tests using `RF = K_full * U_full - F_full`.
+- Missing contribution or untouched free DOF diagnostic tests.
+
+### Reference Artifacts
+- None required. RF reference CSV is not available; use internal equilibrium/reaction tests for this step.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Full-space reaction data is preserved.
+- Reduced system assembly matches constrained/free DOF mapping.
+- Reaction tests use full vectors and the documented sign convention.
+- Unsupported loads and nonlinear behavior are not introduced.
+
+### Handoff Requirements
+- Record assembly and RF recovery behavior in `PROGRESS.md`.
+- Update `PLAN.md` if R-010 remains unresolved or becomes resolved.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect reaction tests for full-vector recovery.
+
+## Do Not
+- Do not allow reduced-system convenience to overwrite the documented RF convention.

phases/1-linear-static-mitc4/step13.md

@@ -0,0 +1,71 @@
+# Step 13: linear-static-analysis-path
+
+## Sprint Contract
+
+### Objective
+Implement the `LinearStaticAnalysis` Template Method path from parsed Domain to solved state and written `U`/`RF` results.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/PRD.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/RESULTS_SCHEMA.md
+- /docs/VERIFICATION_PLAN.md
+- /phases/1-linear-static-mitc4/step8.md
+- /phases/1-linear-static-mitc4/step12.md
+
+### Scope
+- Implement the linear static analysis strategy using the documented common flow: validate, build model, number DOFs, assemble, constrain, solve, reconstruct, recover RF, update state, write results.
+- Store mutable physical quantities and iteration/result state in `AnalysisState`.
+- Route solving through the linear solver interface.
+- Emit minimum Phase 1 result fields `U` and `RF`.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not implement nonlinear, dynamic, thermal, composite, or contact workflows.
+- Do not bypass `DofManager`, assembler, solver interface, or result writer boundaries.
+- Do not compare against stored Abaqus references in this step; that is Step 14.
+
+### Tests To Write First
+- End-to-end small-model test using a deterministic element or minimal fixture where expected `U` and `RF` are known.
+- Singular-system failure test through the analysis path.
+- Result-emission test for `U` and `RF` fields and component order.
+
+### Reference Artifacts
+- None required for this orchestration step.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Strategy + Template Method architecture is visible and not hardwired to only one future analysis type.
+- `AnalysisState` owns mutable solve/result data.
+- `RF` uses full-vector recovery.
+- Results match the documented step/frame/field layout.
+
+### Handoff Requirements
+- Record analysis behavior, tests, and validation in `PROGRESS.md`.
+- Update `PLAN.md` if Phase 1 end-to-end risks remain.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect the analysis path for architecture-boundary shortcuts.
+
+## Do Not
+- Do not make the first end-to-end path depend on local Abaqus execution.

phases/1-linear-static-mitc4/step14.md

@@ -0,0 +1,74 @@
+# Step 14: stored-reference-regression
+
+## Sprint Contract
+
+### Objective
+Add stored-reference regression coverage using accepted Phase 1-compatible cases and preserve `quad_01` as a compatibility/provenance reference.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/ABAQUS_INPUT_SUBSET.md
+- /docs/VERIFICATION_PLAN.md
+- /docs/RESULTS_SCHEMA.md
+- /references/README.md
+- /phases/1-linear-static-mitc4/step9.md
+- /phases/1-linear-static-mitc4/step13.md
+
+### Scope
+- Add automated regression tests comparing FESA `U` output to stored `*_displacements.csv` for Phase 1-compatible `TYPE=S4` linear static cases.
+- Keep `references/quad_01.inp` documented as S4R/NLGEOM provenance and future compatibility target, not a passing Phase 1 parser case.
+- Add or document reference-case requirements for single-element, multi-element, and curved-shell cases.
+- Use internal equilibrium tests for RF unless `*_reactions.csv` artifacts are added.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `references/**`
+- `docs/VERIFICATION_PLAN.md`
+- `docs/ABAQUS_INPUT_SUBSET.md` only for reference compatibility notes
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not require Abaqus execution locally or in CI.
+- Do not make `quad_01.inp` pass by adding S4R, Part/Assembly/Instance, or NLGEOM support.
+- Do not accept missing reference comparisons silently.
+
+### Tests To Write First
+- Regression test harness test that fails when a required displacement CSV is missing or malformed.
+- At least one Phase 1-compatible displacement comparison test when a matching reference case exists.
+- Negative test that `quad_01.inp` remains unsupported for Phase 1 parsing while its CSV can still validate comparator format.
+
+### Reference Artifacts
+- Required solver regression: at least one Phase 1-compatible `TYPE=S4` `.inp` and matching `*_displacements.csv`.
+- Format/provenance only: `references/quad_01.inp` and `references/quad_01_displacements.csv`.
+- Optional RF artifact: `*_reactions.csv`; otherwise RF is checked by internal equilibrium/reaction tests.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- At least one accepted Phase 1 reference comparison runs if the artifact exists.
+- Missing required reference artifacts produce a documented block or failing test, not a silent pass.
+- `quad_01` remains out of Phase 1 parser support.
+- Reference comparisons use documented columns, node-id matching, and tolerances.
+
+### Handoff Requirements
+- Record reference cases, comparison results, and missing artifacts in `PROGRESS.md`.
+- Update `PLAN.md` with remaining reference additions for Phase 1 completion or Phase 2.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect regression logs or test output for actual CSV comparison.
+
+## Do Not
+- Do not relax parser restrictions to make an existing reference input pass.

phases/1-linear-static-mitc4/step15.md

@@ -0,0 +1,75 @@
+# Step 15: phase1-evaluator-closeout
+
+## Sprint Contract
+
+### Objective
+Run the full Phase 1 evaluator pass, close documentation and handoff gaps, and record Phase 2 carryovers.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/PRD.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/ABAQUS_INPUT_SUBSET.md
+- /docs/VERIFICATION_PLAN.md
+- /docs/RESULTS_SCHEMA.md
+- /docs/MITC4_FORMULATION.md
+- /references/README.md
+- /phases/1-linear-static-mitc4/index.json
+
+### Scope
+- Evaluate all Phase 1 Definition of Done items from `PLAN.md` and `docs/PRD.md`.
+- Run the full validation command set and inspect reference-comparison evidence.
+- Produce a concise evaluator report in `PROGRESS.md` or a linked docs artifact.
+- Move unresolved Phase 2 or deferred work into `PLAN.md`.
+
+### Allowed Files
+- `docs/**`
+- `tests/**` only for evaluator-owned missing validation metadata, not feature implementation
+- `references/**` only for documentation or final accepted artifact notes
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not implement missing solver features in the evaluator step.
+- Do not mark Phase 1 complete if validation, reference comparison, MITC4 formulation, RF recovery, or parser rejection evidence is missing.
+- Do not hide remaining risks in prose without putting future tasks in `PLAN.md`.
+
+### Tests To Write First
+- No new implementation tests are expected unless the evaluator identifies missing metadata tests that are needed to prove acceptance.
+
+### Reference Artifacts
+- Required: all accepted Phase 1-compatible reference cases and their `*_displacements.csv` files.
+- Optional: `*_reactions.csv`; otherwise evaluator must verify RF through internal equilibrium tests.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Phase 1 Definition of Done is checked item by item.
+- Parser rejects unsupported Abaqus features with tests.
+- MITC4 baseline tests and documented formulation agree.
+- `U` reference comparison evidence exists for accepted cases.
+- `RF` is recovered from full vectors and verified by available reference or equilibrium tests.
+- `PLAN.md` and `PROGRESS.md` are current.
+
+### Handoff Requirements
+- Record final verdict, validation output, reference evidence, and remaining risks in `PROGRESS.md`.
+- Move future work, Phase 2 candidates, and deferred features into `PLAN.md`.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`; update the top-level phase status if execution is complete.
+
+## Verification
+1. Run the acceptance command.
+2. Perform the evaluator checklist against changed files and test evidence.
+3. Confirm no phase step remains with stale status or missing handoff notes.
+
+## Do Not
+- Do not use evaluator closeout as a place to sneak in broad implementation fixes.

phases/1-linear-static-mitc4/step2.md

@@ -0,0 +1,69 @@
+# Step 2: domain-model
+
+## Sprint Contract
+
+### Objective
+Implement immutable-ish Domain entities for Phase 1 input data: nodes, elements, sets, materials, shell sections, loads, boundaries, and steps.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/PRD.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/ABAQUS_INPUT_SUBSET.md
+- /phases/1-linear-static-mitc4/step1.md
+
+### Scope
+- Add Domain-level value objects and containers preserving input ids and labels.
+- Support Phase 1 shell elements as Abaqus `TYPE=S4` mapped to FESA MITC4.
+- Represent node sets, element sets, linear elastic materials, shell sections, fixed boundary conditions, nodal loads, and linear static steps.
+- Provide lookup APIs and duplicate-id diagnostics without storing equation ids in entities.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not parse Abaqus files in this step.
+- Do not create `AnalysisModel`, `AnalysisState`, or `DofManager`.
+- Do not add support for S4R, pressure loads, nonzero prescribed displacement, Part/Assembly/Instance, dynamics, nonlinear steps, or thermal coupling.
+
+### Tests To Write First
+- Domain construction tests for nodes, elements, sets, materials, shell sections, loads, boundaries, and steps.
+- Duplicate id/name tests with diagnostics.
+- Lookup tests proving labels and ids are preserved.
+
+### Reference Artifacts
+- None.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Domain preserves model definition and is treated as immutable after construction.
+- Node and element objects do not own global equation numbers.
+- Phase 1 object set matches `docs/ABAQUS_INPUT_SUBSET.md`.
+- Tests cover duplicate and missing lookup behavior.
+
+### Handoff Requirements
+- Record changed files and validation in `PROGRESS.md`.
+- Update future tasks in `PLAN.md` only if Domain scope changes.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect Domain APIs for architecture-boundary drift.
+
+## Do Not
+- Do not make Domain depend on solver adapters, analysis strategies, or result writers.

phases/1-linear-static-mitc4/step3.md

@@ -0,0 +1,66 @@
+# Step 3: parser-foundation
+
+## Sprint Contract
+
+### Objective
+Implement the Abaqus input lexical/keyword parser foundation plus Factory + Registry plumbing for Phase 1 objects.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/ABAQUS_INPUT_SUBSET.md
+- /phases/1-linear-static-mitc4/step2.md
+
+### Scope
+- Tokenize Abaqus keyword lines, parameters, data lines, comments, continuations if documented, and source locations.
+- Add a parser result shape that returns Domain data or diagnostics.
+- Add keyword Factory + Registry structure without completing every Phase 1 keyword.
+- Add smoke parsing for a tiny supported subset such as `*Node` and `*Element, TYPE=S4`.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not complete all Phase 1 Abaqus keywords in this step.
+- Do not silently accept unsupported keywords or unknown parameters.
+- Do not parse `quad_01.inp` as a supported Phase 1 case.
+
+### Tests To Write First
+- Lexer tests for keyword names, parameters, comments, blank lines, and source locations.
+- Registry tests for supported and unsupported keyword dispatch.
+- Parser smoke tests for minimal nodes and S4 elements.
+
+### Reference Artifacts
+- None. Existing `references/quad_01.inp` is not a Phase 1 parser acceptance case.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Unsupported input produces diagnostics with line context.
+- Factory + Registry is present and parser logic is not hardwired into Domain constructors.
+- Parser tests do not expand Phase 1 support beyond `docs/ABAQUS_INPUT_SUBSET.md`.
+
+### Handoff Requirements
+- Record progress and validation in `PROGRESS.md`.
+- Update `PLAN.md` if parser-scope risks change.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect parser tests for line-numbered diagnostic coverage.
+
+## Do Not
+- Do not normalize away Abaqus labels that later diagnostics or references need.

phases/1-linear-static-mitc4/step4.md

@@ -0,0 +1,68 @@
+# Step 4: parser-phase1-subset
+
+## Sprint Contract
+
+### Objective
+Complete Phase 1 Abaqus input subset behavior and explicit rejection diagnostics for unsupported features.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/PRD.md
+- /docs/ARCHITECTURE.md
+- /docs/ABAQUS_INPUT_SUBSET.md
+- /docs/VERIFICATION_PLAN.md
+- /phases/1-linear-static-mitc4/step3.md
+
+### Scope
+- Parse `*Node`, `*Element`, `*Nset`, `*Elset`, `*Material`, `*Elastic`, `*Shell Section`, `*Boundary`, `*Cload`, `*Step`, `*Static`, and `*End Step` as documented.
+- Support generated and explicit set definitions only if documented in `docs/ABAQUS_INPUT_SUBSET.md`.
+- Reject unsupported Abaqus constructs with clear diagnostics.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `docs/ABAQUS_INPUT_SUBSET.md` only for clarification of already agreed behavior
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not support `S4R`, `Part`, `Assembly`, `Instance`, `*Include`, pressure loads, nonzero prescribed displacement, `*Density`, or `NLGEOM=YES`.
+- Do not make `quad_01.inp` pass as Phase 1 input.
+- Do not add geometric/material nonlinearity, dynamics, thermal coupling, or mesh quality diagnostics.
+
+### Tests To Write First
+- Positive parser tests for each Phase 1 supported keyword.
+- Negative parser tests for `S4R`, `Part/Assembly/Instance`, `*Include`, `*Density`, pressure loads, nonzero prescribed displacement, and `NLGEOM=YES`.
+- Diagnostics tests for missing required parameters, malformed data rows, and invalid labels.
+
+### Reference Artifacts
+- Format/provenance only: `references/quad_01.inp` may be used to assert that unsupported features are rejected or documented, not as a passing parser case.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Supported keyword coverage matches `docs/ABAQUS_INPUT_SUBSET.md`.
+- Unsupported features fail loudly and specifically.
+- S4 maps to the internal MITC4 shell element type; S4R remains unsupported.
+- Tests include both successful subset parsing and negative diagnostics.
+
+### Handoff Requirements
+- Record parser coverage, unsupported-feature behavior, and validation in `PROGRESS.md`.
+- Update `PLAN.md` if a parser blocker remains.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect tests to ensure unsupported Abaqus features are not silently accepted.
+
+## Do Not
+- Do not widen parser support because a stored reference file happens to contain a keyword.

phases/1-linear-static-mitc4/step5.md

@@ -0,0 +1,69 @@
+# Step 5: domain-validation-diagnostics
+
+## Sprint Contract
+
+### Objective
+Implement Domain validation and singular-prone pre-solve diagnostics required before DOF and solver work.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/ABAQUS_INPUT_SUBSET.md
+- /docs/VERIFICATION_PLAN.md
+- /phases/1-linear-static-mitc4/step4.md
+
+### Scope
+- Validate node, element, set, material, property, load, boundary, and step references.
+- Add singular-prone diagnostics for no active elements, no material/property, no boundary constraints, untouched free DOFs when detectable, and invalid active step data.
+- Keep diagnostics actionable and source-linked where parser information is available.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `docs/VERIFICATION_PLAN.md` only for clarification of diagnostic test expectations
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not implement DofManager, assembly, or solver singularity handling in this step.
+- Do not add mesh quality diagnostics; Phase 1 excludes them.
+- Do not accept unsupported parser features to make validation easier.
+
+### Tests To Write First
+- Validation tests for missing nodes, missing sets, missing materials, missing shell sections, invalid element connectivity, invalid loads, and invalid boundary references.
+- Singular-prone tests for no active elements, unconstrained models, and untouched free DOF candidates where detectable without assembly.
+- Diagnostic payload tests for code, severity, message, and source/model context.
+
+### Reference Artifacts
+- None.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Diagnostics align with `docs/NUMERICAL_CONVENTIONS.md` and `docs/VERIFICATION_PLAN.md`.
+- Validation is separate from parsing and analysis execution.
+- Mesh quality checks were not introduced.
+- Tests cover failure modes, not only valid models.
+
+### Handoff Requirements
+- Record validation coverage and command results in `PROGRESS.md`.
+- Update `PLAN.md` if singular diagnostics require later solver support.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Review negative tests for clear diagnostics and no mesh-quality drift.
+
+## Do Not
+- Do not defer singular diagnostics entirely to the linear solver.

phases/1-linear-static-mitc4/step6.md

@@ -0,0 +1,70 @@
+# Step 6: analysis-model-dof-manager
+
+## Sprint Contract
+
+### Objective
+Implement `AnalysisModelBuilder` and `DofManager` for one active linear static step with six-DOF nodes, constrained/free mapping, equation numbering, sparse-pattern input, and full/reduced vector reconstruction.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/PRD.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /phases/1-linear-static-mitc4/step5.md
+
+### Scope
+- Build an `AnalysisModel` active view from validated `Domain`.
+- Assign six shell DOFs per active node in documented order.
+- Apply fixed boundary conditions by constrained DOF elimination.
+- Produce int64 equation numbers for free DOFs and mappings for constrained DOFs.
+- Provide reconstruction helpers between reduced vectors and full vectors.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not assemble element stiffness or loads.
+- Do not store equation ids on Node or Element objects.
+- Do not solve linear systems or write HDF5 results.
+
+### Tests To Write First
+- DOF numbering tests for simple models with all six components.
+- Constrained/free partition tests for fixed boundary conditions.
+- Reduced/full reconstruction tests including constrained values set to zero for Phase 1.
+- Sparse-pattern input tests using active element connectivity without assembling values.
+
+### Reference Artifacts
+- None.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- `DofManager` owns global equation numbering.
+- ids, sparse indices, and equations remain int64-based.
+- Fixed constraints are handled by elimination, not penalty.
+- Reconstruction supports later full-vector `RF` recovery.
+
+### Handoff Requirements
+- Record DOF behavior, tests, and validation in `PROGRESS.md`.
+- Update `PLAN.md` only for future work or resolved blockers.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect tests for constrained/free and full/reduced mapping edge cases.
+
+## Do Not
+- Do not make constrained DOF elimination depend on reduced-only reaction recovery.

phases/1-linear-static-mitc4/step7.md

@@ -0,0 +1,69 @@
+# Step 7: math-solver-adapters
+
+## Sprint Contract
+
+### Objective
+Implement vector, sparse matrix, and linear solver interfaces plus a deterministic test solver adapter while preserving future MKL/TBB adapter boundaries.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /phases/1-linear-static-mitc4/step6.md
+
+### Scope
+- Add minimal vector and sparse matrix abstractions needed by assembly and linear static solving.
+- Add a linear solver interface with deterministic test implementation.
+- Keep MKL/TBB-specific code behind adapter boundaries if any placeholder is added.
+- Surface solver singularity diagnostics in a structured way.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `docs/ADR.md` if adapter decisions need clarification
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not require Intel oneAPI installation for Phase 1 unit tests.
+- Do not expose MKL, TBB, or HDF5 APIs in solver core headers.
+- Do not implement element assembly or analysis algorithms in this step.
+
+### Tests To Write First
+- Sparse pattern and insertion tests with int64 indices.
+- Deterministic small linear solve tests.
+- Singular solve diagnostic tests.
+- Adapter-boundary tests or compile checks showing core APIs do not include MKL/TBB headers.
+
+### Reference Artifacts
+- None.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Core math interfaces are dependency-clean.
+- Singular solver failures produce diagnostics, not crashes or silent NaNs.
+- Tests cover sparse storage, solve success, and solve failure.
+- Future MKL acceleration remains possible without changing solver core contracts.
+
+### Handoff Requirements
+- Record math interfaces, validation, and adapter caveats in `PROGRESS.md`.
+- Update `PLAN.md` if MKL/TBB integration becomes a future task.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect public headers for third-party API leakage.
+
+## Do Not
+- Do not optimize sparse storage before correctness and testability are established.

phases/1-linear-static-mitc4/step8.md

@@ -0,0 +1,71 @@
+# Step 8: results-writer-minimal
+
+## Sprint Contract
+
+### Objective
+Implement the minimal result model and writer boundary for Phase 1 `U` and `RF` step/frame/field outputs.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/ARCHITECTURE.md
+- /docs/ADR.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/RESULTS_SCHEMA.md
+- /phases/1-linear-static-mitc4/step6.md
+- /phases/1-linear-static-mitc4/step7.md
+
+### Scope
+- Add result data structures for model ids/connectivity plus step/frame/field outputs.
+- Support mandatory Phase 1 fields `U` and `RF` with components `UX`, `UY`, `UZ`, `RX`, `RY`, `RZ`.
+- Add an in-memory or file-backed writer boundary as appropriate for the current build system.
+- If HDF5 is implemented now, keep HDF5 APIs behind an adapter/wrapper.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `docs/RESULTS_SCHEMA.md` only for clarification of agreed schema details
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not add stress, strain, shell force, history, nonlinear frame, thermal, or composite outputs unless R-007 is resolved and docs are updated first.
+- Do not write RF from reduced vectors only.
+- Do not expose HDF5 APIs in solver core headers.
+
+### Tests To Write First
+- Schema tests for step/frame layout and mandatory field names.
+- Component-label and ordering tests for `U` and `RF`.
+- Model id/connectivity storage tests using int64 ids.
+- Adapter-boundary tests if HDF5 is introduced.
+
+### Reference Artifacts
+- None for solver regression. This step only prepares output data consumed by later comparison.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Result layout follows `docs/RESULTS_SCHEMA.md`.
+- `U` and `RF` have six components in the documented order.
+- HDF5, if present, is isolated behind an adapter.
+- No extra Phase 1 outputs were added without resolving R-007.
+
+### Handoff Requirements
+- Record result writer scope and validation in `PROGRESS.md`.
+- Update `PLAN.md` if R-007 changes or output scope remains blocked.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect tests for schema and component ordering.
+
+## Do Not
+- Do not treat a file being created as proof that its schema matches the contract.

phases/1-linear-static-mitc4/step9.md

@@ -0,0 +1,74 @@
+# Step 9: reference-displacement-comparator
+
+## Sprint Contract
+
+### Objective
+Implement the `references/*_displacements.csv` loader and comparator for FESA `U` output.
+
+### Required Reading
+- /AGENTS.md
+- /PROGRESS.md
+- /PLAN.md
+- /docs/README.md
+- /docs/HARNESS_ENGINEERING.md
+- /docs/NUMERICAL_CONVENTIONS.md
+- /docs/VERIFICATION_PLAN.md
+- /docs/RESULTS_SCHEMA.md
+- /references/README.md
+- /phases/1-linear-static-mitc4/step8.md
+
+### Scope
+- Load Abaqus displacement CSV files with columns `Node Label`, `U-U1`, `U-U2`, `U-U3`, `UR-UR1`, `UR-UR2`, `UR-UR3`.
+- Compare by node id, not row order.
+- Implement absolute and relative tolerance behavior with a documented default or configuration path.
+- Report missing columns, duplicate nodes, missing nodes, nonnumeric values, and tolerance failures.
+
+### Allowed Files
+- `include/**`
+- `src/**`
+- `tests/**`
+- `references/**` only for small test fixtures or documentation updates
+- `docs/VERIFICATION_PLAN.md` only for comparator tolerance clarification
+- `docs/RESULTS_SCHEMA.md` only for schema clarification
+- `PLAN.md`
+- `PROGRESS.md`
+- `phases/1-linear-static-mitc4/index.json`
+
+### Explicit Non-Goals
+- Do not require Abaqus execution.
+- Do not treat `references/quad_01.inp` as Phase 1 supported input.
+- Do not compare RF here unless a `*_reactions.csv` contract is added.
+
+### Tests To Write First
+- CSV header validation tests.
+- Node-id matching and row-order independence tests.
+- Absolute/relative tolerance pass/fail tests.
+- Duplicate, missing, and malformed value diagnostics tests.
+- Format-only smoke test using `references/quad_01_displacements.csv` if stable enough for CI.
+
+### Reference Artifacts
+- Format-only: `references/quad_01_displacements.csv`.
+- Required later for solver regression: at least one Phase 1-compatible `TYPE=S4` input and matching displacement CSV.
+
+### Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+### Evaluator Checklist
+- Component mapping matches `docs/VERIFICATION_PLAN.md` and `docs/RESULTS_SCHEMA.md`.
+- Comparison is by node id and independent of row order.
+- Missing or malformed reference data fails with actionable diagnostics.
+- `quad_01` is not used to imply S4R or nonlinear support.
+
+### Handoff Requirements
+- Record comparator behavior, tolerance decision, and validation in `PROGRESS.md`.
+- Update `PLAN.md` if R-009 or reference artifact blockers change.
+- Update the matching phase index entry: use `completed` with a one-line `summary`, or `blocked` with `blocked_reason`, or `error` with `error_message`.
+
+## Verification
+1. Run the acceptance command.
+2. Inspect comparator tests for tolerance and malformed CSV behavior.
+
+## Do Not
+- Do not silently skip reference nodes or components.

phases/index.json

@@ -0,0 +1,8 @@
+{
+  "phases": [
+    {
+      "dir": "1-linear-static-mitc4",
+      "status": "pending"
+    }
+  ]
+}