Gotchas

ax.text() does not accept set_clip_on as a kwarg: Pass it after the fact — t = ax.text(...); t.set_clip_on(True). Passing as a keyword argument raises a TypeError silently or is ignored depending on matplotlib version.

ax.text with data-unit offsets causes figure height explosion: Fixed offsets expressed in data units (e.g., ax.text(x, opex_cursor - 2.0, ...)) work fine on charts with a large y-range but silently push the label far outside the visible axes on charts with a small range. Because ax.text() defaults to clip_on=False, bbox_inches='tight' includes out-of-bounds text in the figure bounding box — producing extreme canvas heights (11,000px+ instead of ~600px). This bites any figure function called for both large-range and small-range data with the same code path (e.g., a Core API chart at $150M range vs. a Concise chart at $0.8M range). Fix: use ax.annotate() with xytext in offset points so the anchor stays in data coordinates but the visual offset is scale-invariant:

# Before (broken for small y-range):
ax.text(x, opex_cursor - 2.0, f"−${total_opex:.1f}M", ha="center", va="top", ...)

# After (safe regardless of y-range):
ax.annotate(f"−${total_opex:.1f}M",
            xy=(x, opex_cursor), xycoords="data",
            xytext=(0, -6), textcoords="offset points",
            ha="center", va="top", ...)

The same applies to labels placed above a bar top: ax.text(x, total_rev + 0.5, ...) floats outside the plot frame on any chart where 0.5 data units exceeds the headroom. Companion risk: even at normal sizes, ax.text without clip_on=True renders outside the axes frame without error — prefer annotate with offset points for all bar-adjacent labels.

Unicode arrows ↑↓→ (U+2191/U+2193/U+2192) do not render: They appear as boxes or missing glyphs in matplotlib via Helvetica Neue or any lualatex-rendered font. Use ASCII +/-/> instead. Safe Unicode in lualatex prose and annotations: ≥ ≤ ≠ ≈ only; × (U+00D7, multiplication sign) is NOT in the Latin Modern font — write "times" or ASCII "x".