The Cornell Conditional Probability Calculator

Use mildly context-sensitive grammars, such as Minimalist Grammars, to work out completions of a sentence-initial substring.
This straightforwardly yields predictions for both surprisal and entropy reduction incremental complexity metrics (see Hale 2016).
For more on Minimalist Grammars check out Stabler (2011) on his publications page or in Oxford Handbooks online.

John Hale