How do you choose between Postgres and tool calling for prompt pack design?

Context: I'm working on ui ux 094 and ran into a decision point.

• What I’ve tried: basic setup + quick benchmarks.
• Constraints: limited time, want something stable.

Question: How do you choose between Postgres and tool calling for prompt pack design?

Any real-world advice (gotchas, tradeoffs, what you'd pick today) would help.