**Overall Verdict:** Accept — This is a complete, professionally grounded, objectively gradable audit task with no material submission defect identified.

**Completeness Check:**

- Instruction: Complete — The scope, six deliverables, seven table schemas, formulas, identifiers, null rules, and eight exception predicates are explicit.
- Inputs: Complete — All six UTF-8 source CSVs match their declared dimensions, hashes, and full keys. Their selected observations agree with the supplied workbook caches.
- Toolchain: Complete — The pinned FOSS stack supports a credible offline, single-machine workflow. Windows execution is documented; resource and solver-duration targets are appropriately distinguished from measured results.
- Reference output: Complete — All six reference deliverables are present. Independent recalculation matches 2,226 regional rows, 1,134 changed-cell rows, 1,113 impact rows, and 1,197 exceptions within the stated tolerance.
- Rubric: Complete — Weights, partial-credit formulas, numeric tolerances, hard failures, and reporting checks are solver-visible and consistent with the evaluator. Hash-linked evidence records 37 passing tests, including the positive reference scoring 1.0.

**File and Task Reachability:**

Attachment classification: `partially_reachable`, solely because independent DuckDB content inspection was unavailable. Task classification: `reachable`.

Both `egrid2023_input_materials.zip` and `egrid2023_reference_evaluation.zip` were downloaded and inspected. Their byte counts match the attachment manifest; archive integrity and packaged member hashes pass, with no unsafe paths or encryption barriers found. Inspection covered the six source CSVs, dictionaries, provenance, inventories, dependency locks, output contracts, reference and gold CSVs, manifests, both provenance workbooks, evaluator and rebuilding code as text, and validation evidence.

The Technical Guide received metadata, representative-text, and sample-render checks rather than page-by-page review. Every reference report page rendered readably, and its required summaries agree with the independently checked tables. The DuckDB files have recognizable format signatures and matching packaged hashes, but their internal schemas and CSV/database parity remain supported by submitted validation evidence rather than independent database inspection. Uploaded programs were not executed, and the evaluator was not rerun.

The completion path is coherent: install compatible dependencies before going offline, process the frozen extracts under the visible contract, generate the six artifacts, and evaluate them against the separate gold package. No solver-visible reference-answer leakage was found.

License keys, accounts, tokens, and other credentials are not required from the contributor. Confidential, proprietary, or internal material may be evaluated as submitted evidence without requiring additional disclosure.

**Special Screening:**

None. The supplied workbook evidence supports authentic observations and revisions. Deliberate mutations are evaluator tests, not the task’s core defects. Public EPA provenance alone does not establish a public benchmark; external publication of this custom task or reference was not verified.

**Recommended Changes:**

The source-preserving design, explicit arithmetic rules, reference separation, and documented validation are substantive strengths. No contributor changes are required.