Function ReadFile

internal/tools/read.go:14–30

ReadFile returns path's contents, truncated to the shared tool-output budget (Truncate). The model gets exact bytes, not a shell-mangled approximation. Per the bash/write/edit convention, filesystem errors come back in the output string, never as a Go error: the model reacts to them like a non-zero

(path string)

// Per the bash/write/edit convention, filesystem errors come back in the output
// string, never as a Go error: the model reacts to them like a non-zero exit.
func ReadFile(path string) string {
	if path == "" {
		return "(empty path)"
	}
	// Refuse non-regular files up front: open(2) on a FIFO blocks forever
	// waiting for a writer (leaking the tool goroutine past Ctrl+C, which
	// cancels the turn but can't unblock the read), and an endless device file
	// (/dev/zero) grows ReadFile's buffer without bound. Stat never blocks.
	if info, err := os.Stat(path); err == nil && !info.Mode().IsRegular() && !info.IsDir() {
		return fmt.Sprintf("(read error: %s is not a regular file)", path)
	}
	raw, err := os.ReadFile(path)
	if err != nil {
		return fmt.Sprintf("(read error: %v)", err)
	}
	return chmctx.Truncate(string(raw))
}

// ReadFileSchema is the OpenAI tool definition for read_file. The description
// nudges the model toward read_file over `cat` so it stops piping source