**Overall Verdict:** Accept — The task is complete, objectively evaluable, and supported by a compliant reference circuit and coherent formal-proof evidence.

**Completeness Check:**

- Instruction: Complete — Deliverables, permitted gates, wire ordering, budgets, theorem interfaces, and prohibited proof shortcuts are explicit.
- Inputs: Complete — The 256-entry truth table matches the fixed Lean table; duplicate input copies agree.
- Toolchain: Complete — Lean 4.19.0, a pinned Mathlib revision, and standard-library Python provide a documented Linux workflow.
- Reference output: Complete — Independent checks confirm 64 AND gates, 316 total gates, exact outputs for all 256 inputs, and identical ordered Lean and JSON circuit data. Supporting proof modules and build logs are included.
- Rubric: Complete — The 20/30/50 allocation clearly distinguishes functional correctness, budget compliance, and complete formal verification.

**File and Task Reachability:**

Attachment classification: `reachable`. All three archives, `sbox_circuit_inputs.zip`, `sbox_circuit_reference.zip`, and `sbox_circuit_evidence.zip`, match their manifest sizes and contain 4, 38, and 54 readable members respectively. No unsafe paths, encrypted members, or corrupt entries were found. Contents are ASCII or UTF-8 text with parseable structured data.

Inspected materials include `task.txt`, `circuit_format.txt`, `truth_table.json`, `CircuitSpec.lean`, reference `circuit.json`, `Core.lean`, `Cases00.lean` through `Cases07.lean`, `Solution.lean`, checking instructions, license and source records, verification scripts and logs, and trial circuits, proof candidates, synthesis sources, and grading evidence. All 256 reference traces agree with independently computed gate values. Reference answers are packaged separately from solver inputs.

Task classification: `reachable`. A single-machine workflow supports synthesis, exhaustive comparison, circuit-data comparison, Lean compilation, and theorem-type and axiom inspection. Uploaded code was inspected but not executed. Lean was unavailable for an independent rebuild; submitted logs report successful checking with only permitted standard logical axioms. No attachment remained unreadable.

The self-test’s selected circuit independently reproduces all outputs but exceeds the total-gate budget, consistent with its reported 20/100 score. Its unfinished proof is explicitly identified.

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. MIT-licensed BearSSL components are documented, but the target is a different composed function. Neither public-benchmark identity nor material AI fabrication is established. External provenance was not independently verified because approved external search was unavailable.

**Recommended Changes:**

The fixed specification, compliant reference, and transparent self-test evidence support acceptance. No changes are required.