Crate prompty 

Prompty — Rust Runtime

Prompty is a markdown file format (.prompty) for LLM prompts. YAML frontmatter defines model, connection, tools, and schema. The markdown body becomes instructions with template variables.

Core Pipeline

The runtime provides 5 public functions (matching TypeScript, Python, C#):

• load() — Parse a .prompty file → typed Prompty agent
• prepare() — Render template + parse role markers → Vec<Message>
• run() — Execute LLM call + process response (takes messages)
• invoke_agent() — One-shot: load → prepare → execute → process
• turn() — Conversation round with optional tool-calling agent loop

Providers

LLM providers are separate crates:

• prompty-openai — OpenAI API
• prompty-foundry — Azure OpenAI / Foundry
• prompty-anthropic — Anthropic Claude

Register providers before calling pipeline functions:

use prompty::registry;

// Register OpenAI (done by prompty_openai::register())
// registry::register_executor("openai", prompty_openai::OpenAIExecutor);
// registry::register_processor("openai", prompty_openai::OpenAIProcessor);

Features

• otel — Enables OpenTelemetry tracing backend

Re-exports

pub use connections::clear_connections;

pub use connections::has_connection;

pub use connections::register_connection;

pub use connections::with_connection;

pub use context::estimate_chars;

pub use context::format_dropped_messages;

pub use context::summarize_dropped;

pub use context::trim_to_context_window;

pub use guardrails::GuardrailError;

pub use guardrails::GuardrailPhase;

pub use guardrails::GuardrailResult;

pub use guardrails::Guardrails;

pub use guardrails::InputGuardrail;

pub use guardrails::OutputGuardrail;

pub use guardrails::ToolGuardrail;

pub use interfaces::ExecuteError;

pub use interfaces::Executor;

pub use interfaces::InvokerError;

pub use interfaces::Parser;

pub use interfaces::Processor;

pub use interfaces::Renderer;

pub use loader::LoadError;

pub use loader::load;

pub use loader::load_async;

pub use loader::load_from_string;

pub use model::Prompty;

pub use pipeline::AgentEvent;

pub use pipeline::AsyncToolFn;

pub use pipeline::Compaction;

pub use pipeline::CompactionFn;

pub use pipeline::EventCallback;

pub use pipeline::ToolFn;

pub use pipeline::ToolHandler;

pub use pipeline::TurnOptions;

pub use pipeline::TurnOptionsBuilder;

pub use pipeline::invoke as invoke_agent;

pub use pipeline::invoke_from_path;

pub use pipeline::prepare;

pub use pipeline::process;

pub use pipeline::register_defaults;

pub use pipeline::render;

pub use pipeline::run;

pub use pipeline::turn;

pub use pipeline::turn_from_path;

pub use pipeline::validate_inputs;

pub use registry::clear_cache;

pub use registry::has_executor;

pub use registry::has_parser;

pub use registry::has_processor;

pub use registry::has_renderer;

pub use registry::invoke_executor;

pub use registry::invoke_format_tool_messages;

pub use registry::invoke_parser;

pub use registry::invoke_pre_render;

pub use registry::invoke_processor;

pub use registry::invoke_renderer;

pub use registry::register_executor;

pub use registry::register_parser;

pub use registry::register_processor;

pub use registry::register_renderer;

pub use steering::Steering;

pub use structured::CastError;

pub use structured::StructuredResult;

pub use structured::cast;

pub use structured::create_structured_result;

pub use structured::from_structured_value;

pub use structured::is_structured_result;

pub use structured::to_structured_value;

pub use structured::unwrap_structured;

pub use tool_dispatch::ToolCallable;

pub use tool_dispatch::ToolHandlerError;

pub use tool_dispatch::ToolHandlerTrait;

pub use tool_dispatch::clear_tool_handlers;

pub use tool_dispatch::clear_tools;

pub use tool_dispatch::dispatch_tool as dispatch_tool_call;

pub use tool_dispatch::has_tool;

pub use tool_dispatch::has_tool_handler;

pub use tool_dispatch::register_tool;

pub use tool_dispatch::register_tool_handler;

pub use tracing::PromptyTracer;

pub use tracing::Tracer;

pub use tracing::console_tracer;

pub use tracing::sanitize_value;

pub use tracing::trace;

pub use tracing::trace_async;

pub use tracing::trace_span;

pub use tracing::trace_span_async;

pub use types::ContentPart;

pub use types::ContentPartKind;

pub use types::Message;

pub use types::PromptyStream;

pub use types::Role;

pub use types::StreamChunk;

pub use types::ThreadMarker;

pub use types::ToolCall;

pub use types::consume_stream_chunks;

Modules

connections

Connection registry — pre-register named connections for kind: "reference".

context

Context window trimming — estimate prompt size and trim messages to fit.

guardrails

Guardrails — input, output, and tool guardrails for the agent loop.

interfaces

Pipeline stage traits — Renderer, Parser, Executor, Processor.

loader

Prompty loader — loads .prompty files into typed Prompty objects.

model

parsers

Parser implementations — convert rendered text into Message lists.

pipeline

Pipeline orchestration — prepare, run, invoke, turn.

prelude

Convenience re-exports for common Prompty types.

registry

Thread-safe invoker registry — register and look up pipeline stage implementations by key.

renderers

Renderer implementations — template engines that produce rendered text.

steering

Steering — inject messages between agent loop iterations.

structured

Structured output — StructuredResult + cast::<T>().

tool_dispatch

Tool registry and dispatch — 3-layer tool resolution.

tracing

Tracing module — observability for the Prompty pipeline.

types

Core pipeline types — Message, ContentPart, ToolCall, PromptyStream, StructuredResult.