diff --git a/Cargo.lock b/Cargo.lock
index 1f19322..851156b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -265,6 +265,7 @@ version = "0.0.1"
 dependencies = [
  "dunce",
  "escargot",
+ "libtest-json",
  "libtest2-harness",
  "once_cell_polyfill",
  "pathdiff",
diff --git a/crates/libtest2-harness/src/harness.rs b/crates/libtest2-harness/src/harness.rs
index 15fa543..41aa93d 100644
--- a/crates/libtest2-harness/src/harness.rs
+++ b/crates/libtest2-harness/src/harness.rs
@@ -19,67 +19,69 @@ impl Harness {
         Self { raw, cases: vec![] }
     }
 
-    pub fn case(mut self, case: impl Case + 'static) -> Self {
+    pub fn case(&mut self, case: impl Case + 'static) {
         self.cases.push(Box::new(case));
-        self
     }
 
-    pub fn cases(mut self, cases: impl IntoIterator<Item = impl Case + 'static>) -> Self {
+    pub fn cases(&mut self, cases: impl IntoIterator<Item = impl Case + 'static>) {
         for case in cases {
             self.cases.push(Box::new(case));
         }
-        self
     }
 
-    pub fn main(mut self) -> ! {
-        let start = std::time::Instant::now();
+    pub fn main(self) -> ! {
+        main(self.raw, self.cases)
+    }
+}
 
-        let raw = match self.raw {
-            Ok(raw) => raw,
-            Err(err) => {
-                eprintln!("{err}");
-                std::process::exit(1)
-            }
-        };
-        let mut parser = cli::Parser::new(&raw);
-        let opts = parse(&mut parser).unwrap_or_else(|err| {
-            eprintln!("{err}");
-            std::process::exit(1)
-        });
+const ERROR_EXIT_CODE: i32 = 101;
 
-        #[cfg(feature = "color")]
-        match opts.color {
-            libtest_lexarg::ColorConfig::AutoColor => anstream::ColorChoice::Auto,
-            libtest_lexarg::ColorConfig::AlwaysColor => anstream::ColorChoice::Always,
-            libtest_lexarg::ColorConfig::NeverColor => anstream::ColorChoice::Never,
-        }
-        .write_global();
+fn main(raw: std::io::Result<Vec<std::ffi::OsString>>, mut cases: Vec<Box<dyn Case>>) -> ! {
+    let start = std::time::Instant::now();
 
-        let mut notifier = notifier(&opts).unwrap_or_else(|err| {
-            eprintln!("{err}");
-            std::process::exit(1)
-        });
-        discover(&start, &opts, &mut self.cases, notifier.as_mut()).unwrap_or_else(|err| {
+    let raw = match raw {
+        Ok(raw) => raw,
+        Err(err) => {
             eprintln!("{err}");
             std::process::exit(1)
-        });
-
-        if !opts.list {
-            match run(&start, &opts, self.cases, notifier.as_mut()) {
-                Ok(true) => {}
-                Ok(false) => std::process::exit(ERROR_EXIT_CODE),
-                Err(e) => {
-                    eprintln!("error: io error when listing tests: {e:?}");
-                    std::process::exit(ERROR_EXIT_CODE)
-                }
-            }
         }
+    };
+    let mut parser = cli::Parser::new(&raw);
+    let opts = parse(&mut parser).unwrap_or_else(|err| {
+        eprintln!("{err}");
+        std::process::exit(1)
+    });
 
-        std::process::exit(0)
+    #[cfg(feature = "color")]
+    match opts.color {
+        libtest_lexarg::ColorConfig::AutoColor => anstream::ColorChoice::Auto,
+        libtest_lexarg::ColorConfig::AlwaysColor => anstream::ColorChoice::Always,
+        libtest_lexarg::ColorConfig::NeverColor => anstream::ColorChoice::Never,
     }
-}
+    .write_global();
 
-const ERROR_EXIT_CODE: i32 = 101;
+    let mut notifier = notifier(&opts).unwrap_or_else(|err| {
+        eprintln!("{err}");
+        std::process::exit(1)
+    });
+    discover(&start, &opts, &mut cases, notifier.as_mut()).unwrap_or_else(|err| {
+        eprintln!("{err}");
+        std::process::exit(1)
+    });
+
+    if !opts.list {
+        match run(&start, &opts, cases, notifier.as_mut()) {
+            Ok(true) => {}
+            Ok(false) => std::process::exit(ERROR_EXIT_CODE),
+            Err(e) => {
+                eprintln!("error: io error when listing tests: {e:?}");
+                std::process::exit(ERROR_EXIT_CODE)
+            }
+        }
+    }
+
+    std::process::exit(0)
+}
 
 fn parse<'p>(parser: &mut cli::Parser<'p>) -> Result<libtest_lexarg::TestOpts, cli::LexError<'p>> {
     let mut test_opts = libtest_lexarg::TestOptsBuilder::new();
diff --git a/crates/libtest2-mimic/Cargo.toml b/crates/libtest2-mimic/Cargo.toml
index 8cea637..0cdda45 100644
--- a/crates/libtest2-mimic/Cargo.toml
+++ b/crates/libtest2-mimic/Cargo.toml
@@ -30,6 +30,7 @@ json = ["libtest2-harness/json"]
 threads = ["libtest2-harness/threads"]
 
 [dependencies]
+libtest-json = { version = "0.0.1", path = "../libtest-json" }
 libtest2-harness = { version = "0.0.1", path = "../libtest2-harness" }
 
 [dev-dependencies]
diff --git a/crates/libtest2-mimic/examples/mimic-simple.rs b/crates/libtest2-mimic/examples/mimic-simple.rs
index beaf47f..a60f10c 100644
--- a/crates/libtest2-mimic/examples/mimic-simple.rs
+++ b/crates/libtest2-mimic/examples/mimic-simple.rs
@@ -15,21 +15,21 @@ fn main() {
 
 // Tests
 
-fn check_toph(_context: &TestContext) -> RunResult {
+fn check_toph(_context: TestContext<'_>) -> RunResult {
     Ok(())
 }
-fn check_katara(_context: &TestContext) -> RunResult {
+fn check_katara(_context: TestContext<'_>) -> RunResult {
     Ok(())
 }
-fn check_sokka(_context: &TestContext) -> RunResult {
+fn check_sokka(_context: TestContext<'_>) -> RunResult {
     Err(RunError::fail("Sokka tripped and fell :("))
 }
-fn long_computation(context: &TestContext) -> RunResult {
+fn long_computation(context: TestContext<'_>) -> RunResult {
     context.ignore_for("slow")?;
 
     std::thread::sleep(std::time::Duration::from_secs(1));
     Ok(())
 }
-fn compile_fail_dummy(_context: &TestContext) -> RunResult {
+fn compile_fail_dummy(_context: TestContext<'_>) -> RunResult {
     Ok(())
 }
diff --git a/crates/libtest2-mimic/src/lib.rs b/crates/libtest2-mimic/src/lib.rs
index 6dfe36b..d2456de 100644
--- a/crates/libtest2-mimic/src/lib.rs
+++ b/crates/libtest2-mimic/src/lib.rs
@@ -24,25 +24,51 @@
 #![warn(clippy::print_stderr)]
 #![warn(clippy::print_stdout)]
 
-pub use libtest2_harness::Harness;
-pub use libtest2_harness::RunError;
-pub use libtest2_harness::RunResult;
-pub use libtest2_harness::TestContext;
-pub use libtest2_harness::TestKind;
+pub use libtest_json::RunMode;
 
-use libtest2_harness::Case;
-use libtest2_harness::Source;
+pub struct Harness {
+    harness: libtest2_harness::Harness,
+}
+
+impl Harness {
+    pub fn with_args(args: impl IntoIterator<Item = impl Into<std::ffi::OsString>>) -> Self {
+        Self {
+            harness: libtest2_harness::Harness::with_args(args),
+        }
+    }
+
+    pub fn with_env() -> Self {
+        Self {
+            harness: libtest2_harness::Harness::with_env(),
+        }
+    }
+
+    pub fn case(mut self, case: Trial) -> Self {
+        self.harness.case(TrialCase { inner: case });
+        self
+    }
+
+    pub fn cases(mut self, cases: impl IntoIterator<Item = Trial>) -> Self {
+        self.harness
+            .cases(cases.into_iter().map(|c| TrialCase { inner: c }));
+        self
+    }
+
+    pub fn main(self) -> ! {
+        self.harness.main()
+    }
+}
 
 pub struct Trial {
     name: String,
     #[allow(clippy::type_complexity)]
-    runner: Box<dyn Fn(&TestContext) -> Result<(), RunError> + Send + Sync>,
+    runner: Box<dyn Fn(TestContext<'_>) -> Result<(), RunError> + Send + Sync>,
 }
 
 impl Trial {
     pub fn test(
         name: impl Into<String>,
-        runner: impl Fn(&TestContext) -> Result<(), RunError> + Send + Sync + 'static,
+        runner: impl Fn(TestContext<'_>) -> Result<(), RunError> + Send + Sync + 'static,
     ) -> Self {
         Self {
             name: name.into(),
@@ -51,22 +77,71 @@ impl Trial {
     }
 }
 
-impl Case for Trial {
+struct TrialCase {
+    inner: Trial,
+}
+
+impl libtest2_harness::Case for TrialCase {
     fn name(&self) -> &str {
-        &self.name
+        &self.inner.name
     }
-    fn kind(&self) -> TestKind {
+    fn kind(&self) -> libtest2_harness::TestKind {
         Default::default()
     }
-    fn source(&self) -> Option<&Source> {
+    fn source(&self) -> Option<&libtest2_harness::Source> {
         None
     }
-    fn exclusive(&self, _: &TestContext) -> bool {
+    fn exclusive(&self, _: &libtest2_harness::TestContext) -> bool {
         false
     }
 
-    fn run(&self, context: &TestContext) -> Result<(), RunError> {
-        (self.runner)(context)
+    fn run(
+        &self,
+        context: &libtest2_harness::TestContext,
+    ) -> Result<(), libtest2_harness::RunError> {
+        (self.inner.runner)(TestContext { inner: context }).map_err(|e| e.inner)
+    }
+}
+
+pub type RunResult = Result<(), RunError>;
+
+#[derive(Debug)]
+pub struct RunError {
+    inner: libtest2_harness::RunError,
+}
+
+impl RunError {
+    pub fn with_cause(cause: impl std::error::Error + Send + Sync + 'static) -> Self {
+        Self {
+            inner: libtest2_harness::RunError::with_cause(cause),
+        }
+    }
+
+    pub fn fail(cause: impl std::fmt::Display) -> Self {
+        Self {
+            inner: libtest2_harness::RunError::fail(cause),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct TestContext<'t> {
+    inner: &'t libtest2_harness::TestContext,
+}
+
+impl<'t> TestContext<'t> {
+    pub fn ignore(&self) -> Result<(), RunError> {
+        self.inner.ignore().map_err(|e| RunError { inner: e })
+    }
+
+    pub fn ignore_for(&self, reason: impl std::fmt::Display) -> Result<(), RunError> {
+        self.inner
+            .ignore_for(reason)
+            .map_err(|e| RunError { inner: e })
+    }
+
+    pub fn current_mode(&self) -> RunMode {
+        self.inner.current_mode()
     }
 }
 
diff --git a/crates/libtest2/examples/tidy.rs b/crates/libtest2/examples/tidy.rs
index 47379e4..9aecc30 100644
--- a/crates/libtest2/examples/tidy.rs
+++ b/crates/libtest2/examples/tidy.rs
@@ -4,7 +4,9 @@ use libtest2::Trial;
 
 fn main() -> std::io::Result<()> {
     let tests = collect_tests()?;
-    libtest2::Harness::with_env().cases(tests).main()
+    let mut harness = libtest2::Harness::with_env();
+    harness.cases(tests);
+    harness.main()
 }
 
 /// Creates one test for each `.rs` file in the current directory or
diff --git a/crates/libtest2/src/lib.rs b/crates/libtest2/src/lib.rs
index 0c21b0b..3ac52ba 100644
--- a/crates/libtest2/src/lib.rs
+++ b/crates/libtest2/src/lib.rs
@@ -75,9 +75,9 @@ impl Case for Trial {
 macro_rules! libtest2_main {
     ( $( $test:path ),* $(,)*) => {
         fn main() {
-            ::libtest2::Harness::with_env()
-                $(.case(::libtest2::Trial::test(::std::stringify!($test), $test)))*
-                .main();
+            let mut harness = ::libtest2::Harness::with_env();
+                $(harness.case(::libtest2::Trial::test(::std::stringify!($test), $test));)*
+                harness.main();
         }
     }
 }