A model card is the standardized document a release ships alongside the weights. It tells you what the model is good for, what it isn't, and what compromises were made. Reading model cards critically is the single most useful "soft skill" in working with LLMs.
Five questions to ask of every model
- What was it trained on? Source datasets, total token count, data cutoff date, deduplication and filtering strategy. Implicit biases and capabilities follow the data.
- Which benchmarks were reported, and at what date? Older benchmarks (MMLU, ARC) are saturated; what's hard in 2026 is GPQA, AIME, SWE-bench, HLE. Be skeptical of benchmark numbers without context.
- What's the license? Apache 2.0 / MIT (use freely), Llama-style community licenses (commercial OK with conditions), research-only licenses (no commercial use), proprietary (API only). License determines who can use it for what.
- What's the context window — and how well is it actually used? "128K context" can mean anything from "trained at 128K" to "extended via YaRN with degraded recall past 32K." Always run a needle-in-a-haystack test.
- Does it support the modalities and languages I need? Many models are English-first; some are explicitly multilingual; some support vision/audio. Check before you commit.
These five questions filter 90% of model-selection decisions. The remaining 10% — does it match the latent style and personality you want? — requires actually using it.