Crate simple_agents_healing 

Response healing system for SimpleAgents.

Implements BAML-inspired JSON parsing and type coercion to handle malformed LLM outputs.

Architecture

The healing system consists of three main components:

1. Jsonish Parser: Three-phase parsing strategy that handles malformed JSON

   • Strip & Fix: Remove markdown, fix commas, normalize quotes
   • Standard Parse: Try serde_json (fast path)
   • Lenient Parse: Character-by-character state machine

2. Coercion Engine: Type coercion with confidence scoring

   • String → Number coercion
   • Fuzzy field matching (case-insensitive, snake_case ↔ camelCase)
   • Union resolution with best-match selection
   • Default value injection

3. Streaming Parser: Incremental parsing for streaming responses

   • Partial value extraction
   • Progressive emission during streaming
   • Annotation support (stream.not_null, stream.done)

Example

use simple_agents_healing::parser::JsonishParser;

let malformed = r#"```json
{"name": "test", "age": 25,}
```"#;

let parser = JsonishParser::new();
let result = parser.parse(malformed).unwrap();

assert_eq!(result.value["name"], "test");
assert_eq!(result.value["age"], 25);
assert!(result.flags.iter().any(|f| matches!(f,
    simple_agent_type::coercion::CoercionFlag::StrippedMarkdown)));

Transparency

All transformations are tracked via CoercionFlags and assigned confidence scores:

• 1.0: Perfect parse, no healing needed
• 0.9-0.99: Minor fixes (markdown, trailing commas)
• 0.7-0.89: Type coercion or fuzzy field matching
• 0.5-0.69: Multiple coercions or truncation
• <0.5: Significant healing required, review recommended

Re-exports

pub use coercion::CoercionConfig;

pub use coercion::CoercionEngine;

pub use parser::JsonishParser;

pub use parser::ParserConfig;

pub use parser::ParserResult;

pub use schema::Field;

pub use schema::ObjectSchema;

pub use schema::Schema;

pub use schema::StreamAnnotation;

pub use streaming::PartialExtractor;

pub use streaming::StreamingParser;

Modules

coercion

Type coercion engine for schema-aligned parsing.

parser

JSON-ish parser for handling malformed LLM outputs.

prelude

Prelude module for convenient imports.

schema

Schema definition system for type validation and coercion.

streaming

Streaming JSON parser for incremental LLM response parsing.

string_utils

String utility functions for case conversion and fuzzy matching.

Structs

CoercionResult

Result of a coercion operation with transparency.

Enums

CoercionFlag

Flag indicating a specific coercion/healing operation.

HealingError

Healing and coercion errors.

Type Aliases

Result

Result type alias using SimpleAgentsError.