ToolOutputConfig

Truncate large tool outputs so they don't exhaust the model's context window.

When a tool returns megabytes of output (e.g. a web_search that fetched a 500 KB page), the full text cannot be sent to the model. ToolOutputConfig truncates via head+tail sampling and optionally writes the full output to a file for later retrieval.

The full file is src/tool_output.rs.

API

pub struct ToolOutputConfig {
    pub max_chars: usize,              // default 32_000
    pub head_chars: usize,             // default 20_000
    pub tail_chars: usize,             // default 10_000
    pub truncation_message: String,    // default "(output truncated)"
    pub save_full_to_file: bool,       // default false
}

pub fn truncate_output(raw: &str, config: &ToolOutputConfig) -> TruncationResult;

pub struct TruncationResult {
    pub truncated: bool,
    pub output: String,      // head + truncation_message + tail
    pub saved_path: Option<PathBuf>,
}

See also

• ToolRuntime — applies truncation after tool execution.