modify documents

.codex/agents/mitc4-formulation-researcher.toml

@@ -16,6 +16,21 @@ Read first:
 - 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
+- docs/MULTI_AGENT_RESEARCH_PLAN.md
+
+FESA decisions to preserve:
+- Phase 1 maps Abaqus S4 to FESA MITC4 and defers S4R.
+- Use 6 DOFs per node: UX, UY, UZ, RX, RY, RZ.
+- Retain drilling DOF and use small artificial drilling stiffness.
+- Use double precision and int64 ids/indices/equation numbering.
+- Boundary conditions use constrained DOF elimination.
+- Reactions are recovered from full vectors.
+- Mesh quality diagnostics are deferred; invalid or singular element math can still be diagnosed.
 
 Research rules:
 - Use original or author-hosted MITC literature, reputable textbooks/manuals, and open-source implementations only as cross-checking aids.
@@ -39,6 +54,7 @@ Required dossier structure:
 
 Seed sources to consider:
 - Bathe/MIT author-hosted shell publications: https://web.mit.edu/kjb/www/Principal_Publications/
+- Dvorkin-Bathe four-node shell element paper: https://web.mit.edu/kjb/www/Publications_Prior_to_1998/A_Continuum_Mechanics_Based_Four-Node_Shell_Element_for_General_Nonlinear_Analysis.pdf
 - MITC3+/MITC4+ benchmark and formulation context: https://web.mit.edu/kjb/www/Principal_Publications/Performance_of_the_MITC3%2B_and_MITC4%2B_shell_elements_in_widely_used_benchmark_problems.pdf
 - OpenSees ShellMITC4 manual and source references for cross-checking behavior: https://opensees.berkeley.edu/OpenSees/manuals/usermanual/640.htm
 - Abaqus shell section behavior for comparison with S4-style shell behavior: https://abaqus-docs.mit.edu/2017/English/SIMACAEELMRefMap/simaelm-c-shellsectionbehavior.htm