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DSRs - typed LM programming in Rust DSRs is a Rust library for building LM-powered applications. You declare each model interaction as a typed contract instead of writing prompts and parsers, compose interactions with ordinary Rust, and get a system where the whole pipeline is also data: printable, diffable, replayable, optimizable, and servable from a single text file.
  • Typed contracts. Inputs, outputs, and instructions are a Rust struct. The library renders the prompt and parses the response into your types; malformed model output becomes a typed error, not a string-parsing bug.
  • Programs as data. A #[module] function is read once at build time and projected into both a runnable function and a .dsrs artifact that cannot drift from the code. The artifact can be checked, diffed, served over HTTP, and embedded back into a build.
  • Recorded runs. Every run is captured as a trace. Strict replay turns recordings into free, deterministic tests; until-divergence replay re-runs only the steps a change actually affects.
  • Optimizers. COPRO, MIPROv2, GEPA, SIMBA, and BootstrapFewShot tune instructions and few-shot demos against your metric and dataset, without modifying your code.
  • Tools, agents, and Code Mode. Models call typed Rust tools in bounded loops, or write one sandboxed JavaScript program that calls all tools in a single round trip. A capability system gates every access at load time.

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Start here

Quickstart

Install, configure a model, and make a typed call in five minutes

How DSRs thinks

The mental model: contracts, programs as data, and the three authoring lanes

Signatures

The first component: typed contracts for LM calls

Examples

Every runnable example in the repository, indexed

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Components

Each component has exactly one page covering what it is, how to use it, and its complete API surface. DSRs is a from-scratch Rust rewrite of the ideas in DSPy, designed around Rust’s type system rather than ported from Python. Source and issues: krypticmouse/DSRs.