# Section 01 Code Review

## Summary
Implementation is a faithful translation of the section plan. No critical issues.

## IMPORTANT

1. **Line validation crashes on malformed point data**: Direct indexing into points without checking length/type. Malformed input like `[[]]` would raise IndexError.
2. **Missing test: nodes exceeding 256 limit**: No test for nodes list > 256 items.
3. **Missing test: line exceeding 256 limit**: No test for line with estimated count > 256.

## SUGGESTION

1. No test for line with missing 'points' key
2. No test for negative spacing on line
3. No test for grid missing 'cols'
4. Line point dimension asymmetry is fragile -- silently drops dims instead of validating
5. Long line in validate_build_params (line 22)

## NITPICK

1. `elif` after return is unnecessary (stylistic)
2. `ctx` parameter accepted but unused (follows existing pattern)
