PurRAssist

Assistance for AIs that get the details almost right. This facade exposes the pure recovery engines and isolated syntax integration.

Status: 0.1.0. This crate is the Rust interface of PurRAssist, one engine with three equal interfaces: the Rust crates (this one), the MCP server and the CLI (purrassist-cli).

use purrassist::{Outcome, RecoveryRequest, Schema};

let schema = Schema::compile(r#"{
  "type": "object",
  "required": ["temperature"],
  "properties": {"temperature": {"type": "number"}},
  "additionalProperties": false
}"#)?;

let answer = schema.recover("[[{temperatur: '42',}]]", RecoveryRequest::default());
match answer.outcome {
    Outcome::Resolved(value) => assert_eq!(value.to_json(), r#"{"temperature":42}"#),
    Outcome::BestGuess(value) => println!("inferred: {}", value.to_json()),
    Outcome::Ambiguous(values) => println!("{} interpretations", values.len()),
    Outcome::Unresolved => println!("{}", answer.receipt.stopped),
}
# Ok::<(), purrassist::schema::SchemaError>(())

Tool-call recovery

tool_call recovers the tool calls of one raw model turn against the OpenAI, MCP, or Anthropic declarations the model was shown (read byte for byte), with per-call outcomes, itemized repairs, the turn's finish, and a receipt; it never executes a call. Twelve dialects ship: qwen3-coder-xml.v1, hermes.v1, openai-tool-calls.v1, llama3-json.v1, mistral-v3.v1, mistral-v11.v1, deepseek-v3.1.v1, deepseek-v3.v1, kimi-k2.v1, anthropic-tool-use.v1, harmony.v1, and bare-json.v1.

use purrassist::Outcome;
use purrassist::tool_call::{ToolRecoveryRequest, ToolSet};
let declarations = r#"[{"type":"function","function":{"name":"get_weather","parameters":{"type":"object","properties":{"city":{"type":"string"}},"required":["city"]}}}]"#;
let tools = ToolSet::from_openai(declarations, purrassist::Budget::default()).unwrap();
let turn = br#"[TOOL_CALLS] [{"name": "get_weather", "arguments": {"city": "Oslo"}}]"#;
let result = tools.recover(turn, &ToolRecoveryRequest::default());
let Outcome::Resolved(calls) = result.outcome else { panic!("unexpected outcome") };
assert_eq!(calls.calls[0].tool.as_deref(), Some("get_weather"));
assert_eq!(calls.calls[0].dialect.id(), "mistral-v3.v1");

A tool's schema and its typed arguments can come from one Rust struct, through the purrassist::ToolDefinition and purrassist::ToolEnum derives (purrassist-derive):

use purrassist::json;
use purrassist::tool_call::{FromNode, ToolArguments};

#[derive(purrassist::ToolEnum, Debug, PartialEq)]
enum Order {
    Asc,
    Desc,
}

/// Search the index.
#[derive(purrassist::ToolDefinition, Debug, PartialEq)]
#[tool(effects = read_only)]
struct Search {
    /// What to look for.
    query: String,
    #[param(default = 10)]
    limit: u32,
    order: Option<Order>,
}

assert_eq!(Search::tool_definition().name(), "search");
let arguments = json::parse(r#"{"query": "cats", "order": "Desc"}"#)?;
assert_eq!(
    Search::from_node(&arguments),
    Ok(Search { query: "cats".into(), limit: 10, order: Some(Order::Desc) }),
);
# Ok::<(), Box<dyn std::error::Error>>(())

Inspect every result's status and receipt. Validation does not turn an invented value into a fact. Ambiguity and resource exhaustion are explicit outcomes.

Version 0.1.0, with executable conformance, recovery, resource, and portability qualification. Capabilities, known limitations, verification, and provenance are recorded in the qualification record. First-party code is licensed under MIT OR Apache-2.0 OR MulanPSL-2.0.