**Overall Verdict:** Borderline Accept — the timing task and primary metric are viable, but the score-video cursor behavior is insufficiently specified for reproducible visual evaluation across solver-selected scans.

**Completeness Check:**
- Instruction: Unclear — timestamp requirements are clear, but the red line’s duration, movement, page transitions, and placement across differing score editions are underdefined.
- Inputs: Complete — the supplied recording is a readable, complete 528.829-second stereo PCM WAV.
- Toolchain: Complete — Shotcut on Windows provides a viable production path, and the score-acquisition workflow is stated.
- Reference output: Complete — the protected reference contains 553 sequential, strictly increasing measure timestamps within the recording duration.
- Rubric: Unclear — the 90% numerical timing metric is objective, but the 10% vision criterion lacks reproducible cursor and score-layout acceptance rules.

**File and Task Reachability:**
The attachment set is `reachable`, while the end-to-end task is `conditionally_reachable` pending clarification of the visual target. Both manifest attachments were inspected: `recording.wav` is a structurally coherent 101,535,356-byte RIFF/WAVE file containing 48 kHz, 16-bit stereo PCM audio, and `reference.txt` is an 8,069-byte ASCII file containing 553 well-formed rows numbered 1 through 553. The reference uses six decimal places rather than the solver-facing three, but numerical comparison with a 50 ms tolerance makes this nonmaterial. No manifest attachment was omitted. The recording’s claimed musical identity and the availability and worldwide public-domain status of a particular score scan could not be independently verified within the permitted evidence boundary. The workflow otherwise supports listening and annotation, acquiring a qualifying score, authoring the synchronized video in Shotcut, exporting both required artifacts, and evaluating row count, duration, timestamps, and sampled video frames. 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

**Recommended Changes:**
The audio input, protected timestamp reference, hard gates, and primary numerical scoring method are coherent. Define one exact score-video convention: whether the red line is instantaneous, held over the current measure, or continuously interpolated; how it advances within systems and across pages; whether any qualifying score edition is accepted; and the spatial and temporal tolerances used by the vision judge.