diff --git a/.github/actions/test/action.yaml b/.github/actions/test/action.yaml
index 0a48221..fcdce3e 100644
--- a/.github/actions/test/action.yaml
+++ b/.github/actions/test/action.yaml
@@ -10,7 +10,7 @@ inputs:
   erlang-version:
     description: erlang-otp version
     required: false
-    default: 24.3.4
+    default: 26.2.2
 
 runs:
   using: composite
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 47e5cc1..0184db6 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        erlang: ["24.2"]
+        erlang: ["26.2.2"]
     steps:
       - uses: actions/checkout@v2
       - uses: ./.github/actions/test
diff --git a/src/gladvent/internal/cmd/run.gleam b/src/gladvent/internal/cmd/run.gleam
index 33d75ed..b8ced64 100644
--- a/src/gladvent/internal/cmd/run.gleam
+++ b/src/gladvent/internal/cmd/run.gleam
@@ -22,6 +22,7 @@ type AsyncResult =
 
 type RunErr {
   FailedToReadInput(String)
+  FailedToParseInput(String)
   Unregistered(Day)
   Other(String)
 }
@@ -42,6 +43,7 @@ fn run_err_to_snag(err: RunErr) -> Snag {
     Unregistered(day) ->
       "day" <> " " <> int.to_string(day) <> " " <> "unregistered"
     FailedToReadInput(input_path) -> "failed to read input file: " <> input_path
+    FailedToParseInput(err) -> "failed to parse input: " <> err
     Other(s) -> s
   }
   |> snag.new
@@ -61,7 +63,7 @@ fn string_trim(s: String, dir: Direction, sub: String) -> String {
 fn do_trim(a: String, b: Direction, c: Charlist) -> String
 
 fn do(year: Int, day: Day, runners: RunnerMap, allow_crash: Bool) -> RunResult {
-  use #(pt_1, pt_2) <- result.then(
+  use #(pt_1, pt_2, parse) <- result.try(
     runners
     |> map.get(day)
     |> result.replace_error(Unregistered(day)),
@@ -70,24 +72,35 @@ fn do(year: Int, day: Day, runners: RunnerMap, allow_crash: Bool) -> RunResult {
   let input_path =
     "input/" <> int.to_string(year) <> "/" <> int.to_string(day) <> ".txt"
 
-  use input <- result.then(
+  use input <- result.try(
     input_path
     |> simplifile.read()
     |> result.map(string_trim(_, Both, "\n"))
     |> result.replace_error(FailedToReadInput(input_path)),
   )
 
+  let parse = option.unwrap(parse, dynamic.from)
+
   case allow_crash {
-    True -> Ok(#(Ok(pt_1(input)), Ok(pt_2(input))))
+    True -> {
+      let input = parse(input)
+      Ok(#(Ok(pt_1(input)), Ok(pt_2(input))))
+    }
     False -> {
+      use input <- result.try(
+        fn() { parse(input) }
+        |> erlang.rescue
+        |> result.map_error(crash_to_string)
+        |> result.map_error(FailedToParseInput),
+      )
       let pt_1 =
         fn() { pt_1(input) }
         |> erlang.rescue
-        |> result.map_error(crash_to_string)
+        |> result.map_error(crash_to_solve_err)
       let pt_2 =
         fn() { pt_2(input) }
         |> erlang.rescue
-        |> result.map_error(crash_to_string)
+        |> result.map_error(crash_to_solve_err)
       Ok(#(pt_1, pt_2))
     }
   }
@@ -149,13 +162,18 @@ fn gleam_err_to_string(g: GleamErr) -> String {
   )
 }
 
-fn crash_to_string(err: erlang.Crash) -> SolveErr {
+fn crash_to_string(err: erlang.Crash) -> String {
   crash_to_dyn(err)
   |> decode_gleam_err()
   |> result.map(gleam_err_to_string)
   |> result.lazy_unwrap(fn() {
     "run failed for some reason: " <> string.inspect(err)
   })
+}
+
+fn crash_to_solve_err(err: erlang.Crash) -> SolveErr {
+  err
+  |> crash_to_string
   |> RunFailed
 }
 
diff --git a/src/gladvent/internal/runners.gleam b/src/gladvent/internal/runners.gleam
index 6cc6784..debaecd 100644
--- a/src/gladvent/internal/runners.gleam
+++ b/src/gladvent/internal/runners.gleam
@@ -8,13 +8,13 @@ import gleam/result
 import gleam
 import gleam/dynamic.{type Dynamic}
 import gleam/int
-import gleam/function
+import gleam/option.{type Option}
 
 pub type PartRunner =
-  fn(String) -> Dynamic
+  fn(Dynamic) -> Dynamic
 
 pub type DayRunner =
-  #(PartRunner, PartRunner)
+  #(PartRunner, PartRunner, Option(fn(String) -> Dynamic))
 
 pub type RunnerMap =
   Map(Day, DayRunner)
@@ -80,15 +80,16 @@ fn get_runner(year: Int, filename: String) -> Result(#(Day, DayRunner)) {
     |> to_module_name
     |> atom.create_from_string
 
-  let p = case function_exists(year, filename, module, "parse") {
-    Ok(p) -> p
-    Error(_) -> function.identity
-  }
-
   use pt_1 <- result.then(function_exists(year, filename, module, "pt_1"))
   use pt_2 <- result.then(function_exists(year, filename, module, "pt_2"))
 
-  Ok(#(day, #(function.compose(p, pt_1), function.compose(p, pt_2))))
+  Ok(
+    #(day, #(
+      pt_1,
+      pt_2,
+      option.from_result(function_exists(year, filename, module, "parse")),
+    )),
+  )
 }
 
 pub fn build_from_days_dir(year: Int) -> Result(Map(Day, DayRunner)) {