diff --git a/tools/confedit/Cargo.toml b/tools/confedit/Cargo.toml
new file mode 100644
index 0000000..2c043fa
--- /dev/null
+++ b/tools/confedit/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "confedit"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+loadstone_config = { path = "../../loadstone_config" }
+ron = "*"
+serde = "*"
+clap = "2"
diff --git a/tools/confedit/README.md b/tools/confedit/README.md
new file mode 100644
index 0000000..9305c24
--- /dev/null
+++ b/tools/confedit/README.md
@@ -0,0 +1,11 @@
+# confedit
+
+A tool to modify loadstone configuration files.
+
+## Usage
+
+Confedit expects a configuration in its standard input. Provide arguments to
+specify how the configuration will be modified. The output configuration file
+will be written to its standard output.
+
+Do `cargo run -- --help` for help information.
diff --git a/tools/confedit/src/main.rs b/tools/confedit/src/main.rs
new file mode 100644
index 0000000..13dacd5
--- /dev/null
+++ b/tools/confedit/src/main.rs
@@ -0,0 +1,226 @@
+use std::{borrow::Cow, io::{Read, Write}};
+use clap::clap_app;
+use loadstone_config::{Configuration, features::{Greetings, Serial}, memory::Bank, security::{SecurityConfiguration, SecurityMode}};
+
+struct Arguments {
+    internal_banks: Option<Vec<u32>>,
+    external_banks: Option<Vec<u32>>,
+    greeting: Option<String>,
+    golden_bank: Option<Option<usize>>,
+    bootable_bank: Option<usize>,
+    recovery: Option<bool>,
+}
+
+fn read_input_string() -> Result<String, String> {
+    let mut input = String::default();
+    let result = std::io::stdin().read_to_string(&mut input);
+    match result {
+        Ok(_) => Ok(input),
+        Err(e) => Err(format!("failed to read from standard input stream: {}.", e)),
+    }
+}
+
+fn get_input_configuration(string: String) -> Result<Configuration, String> {
+    if string.is_empty() {
+        Ok(Configuration {
+            security_configuration: SecurityConfiguration {
+                security_mode: SecurityMode::Crc,
+                ..SecurityConfiguration::default()
+            },
+            ..Configuration::default()
+        })
+    } else {
+        ron::from_str(&string)
+            .map_err(|e| format!("failed to load configuration from input: {}.", e))
+    }
+}
+
+fn modify_configuration(mut configuration: Configuration, arguments: Arguments) -> Result<Configuration, String> {
+    if let Some(greeting) = arguments.greeting {
+        let old_demo = match configuration.feature_configuration.greetings {
+            Greetings::Default => Cow::from(""),
+            Greetings::Custom { demo, .. } => demo,
+        };
+
+        configuration.feature_configuration.greetings = Greetings::Custom {
+            loadstone: Cow::from(greeting),
+            demo: old_demo,
+        };
+    }
+
+    if let Some(bank) = arguments.golden_bank {
+        configuration.memory_configuration.golden_index = bank;
+    }
+
+    if let Some(bank) = arguments.bootable_bank {
+        configuration.memory_configuration.internal_memory_map.bootable_index = Some(bank);
+    }
+
+    if let Some(recovery) = arguments.recovery {
+        let serial = &mut configuration.feature_configuration.serial;
+        if let Serial::Enabled { recovery_enabled, .. } = serial {
+            *recovery_enabled = recovery;
+        } else {
+            return Err(String::from("cannot enable serial recovery since serial is not enabled"));
+        }
+    }
+
+    if let Some(banks) = arguments.internal_banks {
+        let mut offset = configuration.memory_configuration.internal_memory_map.bootloader_location
+            + (configuration.memory_configuration.internal_memory_map.bootloader_length_kb * 1024);
+
+        configuration.memory_configuration.internal_memory_map.banks = banks.into_iter()
+            .map(|size| {
+                let bank = Bank {
+                    size_kb: size,
+                    start_address: offset,
+                };
+                offset += size * 1024;
+                bank
+            }).collect();
+    }
+
+    if let Some(banks) = arguments.external_banks {
+        let mut offset = 0;
+
+        configuration.memory_configuration.external_memory_map.banks = banks.into_iter()
+            .map(|size| {
+                let bank = Bank {
+                    size_kb: size,
+                    start_address: offset,
+                };
+                offset += size * 1024;
+                bank
+            }).collect();
+    }
+
+    Ok(configuration)
+}
+
+fn get_output_string(configuration: Configuration) -> Result<String, String> {
+    ron::to_string(&configuration)
+        .map_err(|e| format!("failed to write configuration to output: {}.", e))
+}
+
+fn write_output_string(string: String) -> Result<(), String> {
+    std::io::stdout().write_all(string.as_bytes())
+        .map_err(|e| format!("failed to write output to standard output stream: {}.", e))
+}
+
+fn run() -> Result<(), String> {
+    let arguments = run_clap()?;
+    let input = read_input_string()?;
+    let configuration = get_input_configuration(input)?;
+    let new_configuration = modify_configuration(configuration, arguments)?;
+    let output = get_output_string(new_configuration)?;
+    write_output_string(output)
+}
+
+fn to_decimal_digit(c: char) -> Option<u32> {
+    match c {
+        '0' => Some(0),
+        '1' => Some(1),
+        '2' => Some(2),
+        '3' => Some(3),
+        '4' => Some(4),
+        '5' => Some(5),
+        '6' => Some(6),
+        '7' => Some(7),
+        '8' => Some(8),
+        '9' => Some(9),
+        _ => None
+    }
+}
+
+fn parse_banks(string: &str) -> Result<Vec<u32>, String> {
+    let mut sizes = Vec::new();
+    let mut size : u32 = 0;
+    for c in string.chars() {
+        if let Some(d) = to_decimal_digit(c) {
+            size = (size * 10) + d;
+        } else if c == ',' {
+            sizes.push(size);
+            size = 0;
+        } else {
+            return Err(format!("bank size list expects decimal digits and commas, found {}.", c))
+        }
+    };
+
+    if size > 0 {
+        sizes.push(size);
+    }
+
+    Ok(sizes)
+}
+
+fn run_clap() -> Result<Arguments, String> {
+    let matches = clap_app!(app =>
+        (name: env!("CARGO_PKG_NAME"))
+        (version: env!("CARGO_PKG_VERSION"))
+        (@arg greeting: --greeting +takes_value)
+        (@arg golden: --golden +takes_value)
+        (@arg bootable: --bootable +takes_value)
+        (@arg recovery: --recovery +takes_value)
+        (@arg internal_banks: --internalbanks +takes_value)
+        (@arg external_banks: --externalbanks +takes_value)
+    )
+    .get_matches();
+
+    let greeting = matches.value_of("greeting").map(String::from);
+
+    let golden_bank = if let Some(s) = matches.value_of("golden") {
+        if s == "none" {
+            Some(None)
+        } else {
+            let n = s.parse::<usize>()
+                .map_err(|_| "--golden-bank expected an unsigned integer argument".to_string())?;
+            Some(Some(n))
+        }
+    } else {
+        None
+    };
+
+    let bootable_bank = match matches.value_of("bootable") {
+        None => None,
+        Some(string) => {
+            let n = string.parse::<usize>()
+                .map_err(|_| "--golden-bank expected an unsigned integer argument".to_string())?;
+            Some(n)
+        },
+    };
+
+    let recovery = match matches.value_of("recovery") {
+        None => None,
+        Some("true") => Some(true),
+        Some("false") => Some(false),
+        Some(_) => return Err("--recovery expected a boolean argument".to_string()),
+    };
+
+    let internal_banks = match matches.value_of("internal_banks") {
+        None => None,
+        Some(string) => Some(parse_banks(string)?),
+    };
+
+    let external_banks = match matches.value_of("external_banks") {
+        None => None,
+        Some(string) => Some(parse_banks(string)?),
+    };
+
+    Ok(Arguments {
+        internal_banks,
+        external_banks,
+        greeting,
+        golden_bank,
+        bootable_bank,
+        recovery,
+    })
+}
+
+fn main() {
+    let result = run();
+
+    if let Err(e) = result {
+        eprintln!("Error: {}", e);
+        std::process::exit(1)
+    }
+}