Flint, a visualization intermediate language introduced by Microsoft Research, helps AI agents generate expressive, visually polished charts from simple, human-editable specifications. Flint leverages semantic data types to express meanings of data, helping the compiler choose appropriate scales, baselines, formatting, and color schemes. It automatically manages sizing, spacing, labels, and layout so charts remain readable as cardinality and density change, without explicit user configurations. A single Flint specification can compile to Vega-Lite, Apache ECharts, or Chart.js without rewriting the chart from scratch. The open-source project includes the flint-chart library and the flint-chart-mcp server, so agents can create, validate, and render charts directly in chat or coding environments. The article notes that modern visualization libraries expose controls, but short specifications relying on system defaults often produce uninspiring charts, while polished visualizations require detailed specifications that are verbose, fragile, and error-prone. This trade-off becomes sharper as large language models (LLMs) and AI agents take on more visualization work. Flint addresses this by providing a compact specification that agents can produce reliably, people can edit directly, and a system can compile into a well-designed chart.