ferrin-tool

Tool definitions for Ferrin: Tool, ToolKind, ToolSet, the execution contract (ToolExecute, ToolOutput, ToolContext, ToolError), approval declarations (NeedsApproval), model-output normalisation, caller restrictions, tool fingerprints and (feature sandbox) the Sandbox trait with a local-process implementation.

Part of the Ferrin workspace. Design: docs/01-architecture/06-tool-system.md, ADR 0012.

Example

use ferrin_tool::Tool;
use ferrin_tool::ToolSet;
use ferrin_tool::ToolError;

#[derive(serde::Deserialize, schemars::JsonSchema)]
struct GetWeather {
    /// City name.
    city: String,
}

#[derive(serde::Serialize)]
struct Weather { temperature_c: f32 }

fn tools() -> Result<ToolSet, ferrin_tool::DuplicateToolError> {
    let get_weather = Tool::function::<GetWeather>()
        .description("Get the current weather for a city.")
        .execute(|input: GetWeather, _ctx| async move {
            let _ = input.city;
            Ok::<_, ToolError>(Weather { temperature_c: 21.5 })
        })
        .build();
    ToolSet::new().insert("get_weather", get_weather)
}

Tool call parsing, approval resolution, scheduling and repair live in ferrin-core; this crate describes tools and runs single executions.

Features

License

Apache-2.0. See LICENSE and NOTICE. Portions of this crate are derived from the Vercel AI SDK (Apache-2.0); the crate and module documentation carry the attribution.