Comparison
Compression is selection; summarization is rewriting.
A summary asks a model to generate a new representation. Tokz selects source spans without paraphrasing them, so the retained material can be checked against the input.
Use summarization when synthesis is the goal
A summary can combine themes, resolve narrative structure, and produce a compact explanation. That generation step also introduces model cost, latency, and possible omissions.
Use extractive compression when provenance matters
Source-backed spans are useful for JSON, logs, tool output, and regulated or auditable context where a rewritten sentence is not an acceptable substitute.
Neither removes evaluation
Selection can drop an answer and a summary can omit a commitment. Test required probes on the original workload and preserve the source for later inspection.