diff --git a/Project.toml b/Project.toml
index abae127..9e45ee7 100644
--- a/Project.toml
+++ b/Project.toml
@@ -9,6 +9,7 @@ Format = "1fa38f19-a742-5d3f-a2b9-30dd87b9d5f8"
 Preferences = "21216c6a-2e73-6563-6e65-726566657250"
 Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
+ThreadSafeDicts = "4239201d-c60e-5e0a-9702-85d713665ba7"
 
 [compat]
 DelimitedFiles = "1"
@@ -16,4 +17,5 @@ Format = "1.3.7"
 Preferences = "1.5.0"
 Printf = "1"
 SparseArrays = "1"
+ThreadSafeDicts = "0.1.6"
 julia = "1.10"
diff --git a/src/DiagHamInterface.jl b/src/DiagHamInterface.jl
index a7e83e1..6398097 100644
--- a/src/DiagHamInterface.jl
+++ b/src/DiagHamInterface.jl
@@ -4,6 +4,7 @@ Interface to the DiagHam library.
 module DiagHamInterface
 
 export execute_diagham_script
+export diagham_command
 export install_diagham
 
 export read_matrix_from_txt
@@ -11,13 +12,14 @@ export write_to_txt
 export write_matrix_elements
 
 using DelimitedFiles
-using Format: cfmt
+using Format
 using SparseArrays
 using Preferences
+using ThreadSafeDicts
 
 include("utility/backup.jl")
 include("utility/diagham_path.jl")
-include("utility/execute_script.jl")
+include("utility/diagham_script.jl")
 include("utility/diagham_install.jl")
 include("utility/fileending.jl")
 include("utility/numbers.jl")
diff --git a/src/utility/execute_script.jl b/src/utility/diagham_script.jl
similarity index 69%
rename from src/utility/execute_script.jl
rename to src/utility/diagham_script.jl
index ce166d2..609a55f 100644
--- a/src/utility/execute_script.jl
+++ b/src/utility/diagham_script.jl
@@ -1,28 +1,16 @@
 """
-    execute_diagham_script(execute; kwargs...)
-
-Run a DiagHam executable. Kwargs are converted to CLI flags (`_` → `-`).
-Single-char keys use `-k`, multi-char use `--key`. Boolean `true` adds flag, `false` omits.
-
-The kwargs of `Cmd()` are supported.
+    diagham_command(execute; kwargs...)
+Construct a command string for running a DiagHam executable with specified kwargs as CLI flags.
 """
-function execute_diagham_script(execute::AbstractString; kwargs...)
-    return execute_diagham_script([execute]; kwargs...)
+function diagham_command(execute::AbstractString; kwargs...)
+    return diagham_command([execute]; kwargs...)
 end
-
-function execute_diagham_script(
+function diagham_command(
         execute::AbstractVector{<:AbstractString};
         diagham_path::AbstractString = get_diagham_path(),
-        ignorestatus::Bool = false,
-        detach::Bool = false,
-        windows_verbatim::Bool = false,
-        windows_hide::Bool = false,
-        env = nothing,
-        dir = "",
         kwargs...
     )
     warn_about_diagham_path()
-
     ex_file = first(execute)
     execute[1] = joinpath(diagham_path, ex_file)
     execute = prod(execute)
@@ -31,10 +19,7 @@ function execute_diagham_script(
     for (k, v) in kwargs
         execute *= diagham_kwarg(k, v)
     end
-
-    execute = Cmd(split(execute, " "))
-    cmd = Cmd(execute; ignorestatus = ignorestatus, detach = detach, windows_verbatim = windows_verbatim, windows_hide = windows_hide, env = env, dir = dir)
-    return run(cmd)
+    return execute
 end
 
 function diagham_kwarg(key, value)
@@ -49,3 +34,33 @@ function diagham_kwarg(key, value)
     end
     return ""
 end
+
+"""
+    execute_diagham_script(execute; kwargs...)
+
+Run a DiagHam executable. Kwargs are converted to CLI flags (`_` → `-`).
+Single-char keys use `-k`, multi-char use `--key`. Boolean `true` adds flag, `false` omits.
+
+The kwargs of `Cmd()` and `run()` are supported.
+"""
+function execute_diagham_script(execute::AbstractString; kwargs...)
+    return execute_diagham_script([execute]; kwargs...)
+end
+function execute_diagham_script(
+        execute::AbstractVector{<:AbstractString};
+        diagham_path::AbstractString = get_diagham_path(),
+        ignorestatus::Bool = false,
+        detach::Bool = false,
+        windows_verbatim::Bool = false,
+        windows_hide::Bool = false,
+        env = nothing,
+        dir = "",
+        wait::Bool = true,
+        cleanup::Bool = false,
+        kwargs...
+    )
+    execute = diagham_command(execute; diagham_path, kwargs...)
+    execute = Cmd(split(execute, " "))
+    cmd = Cmd(execute; ignorestatus = ignorestatus, detach = detach, windows_verbatim = windows_verbatim, windows_hide = windows_hide, env = env, dir = dir)
+    return run(cmd; wait = wait)
+end
diff --git a/src/utility/numbers.jl b/src/utility/numbers.jl
index dbff702..1de0b90 100644
--- a/src/utility/numbers.jl
+++ b/src/utility/numbers.jl
@@ -1,3 +1,6 @@
+# Maps the format string (e.g. "%.5f") to the compiled formatter Function.
+const LOCAL_FORMAT_CACHE = ThreadSafeDict{String, Function}()
+
 """
     format_with_precision(x; atol=eps(float(T)), mode=:auto, maxdigits=20)
 
@@ -5,7 +8,7 @@ Format number `x` as a string with absolute precision `atol`.
 Mode `:auto` uses `%f` for `[1e-3, 1e6)`, else `%e`. Use `:f` or `:e` to force format.
 """
 function format_with_precision(x::T; atol = eps(float(T)), mode::Symbol = :auto, maxdigits::Int = 20) where {T <: Real}
-    x == 0 && return "0.0"
+    iszero(x) && return "0.0"
     absx = abs(x)
     abs_atol = abs(atol)
 
@@ -16,11 +19,21 @@ function format_with_precision(x::T; atol = eps(float(T)), mode::Symbol = :auto,
         log10_atol = log10(abs_atol)
         p = ceil(Int, exp10 - log10_atol)
         p = clamp(p, 0, maxdigits)
-        return cfmt("%.$(p)e", x)
+
+        formatter = get_threadsafe_formatter("%.$(p)e")
+        return formatter(x)
     else
         p = ceil(Int, -log10(abs_atol))
         p = clamp(p, 0, maxdigits)
-        return cfmt("%.$(p)f", x)
+
+        formatter = get_threadsafe_formatter("%.$(p)f")
+        return formatter(x)
+    end
+end
+
+function get_threadsafe_formatter(fmtstr::String)
+    return get!(LOCAL_FORMAT_CACHE, fmtstr) do
+        Format.generate_formatter(fmtstr)
     end
 end