diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index a4f407791..c7ba287e7 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -11,3 +11,10 @@ updates:
     ignore:
       - dependency-name: "schemars"
         versions: [">=0.9.0"]
+  - package-ecosystem: "cargo"
+    directory: "/progenitor-impl/tests/output"
+    schedule:
+      interval: "weekly"
+    ignore:
+      - dependency-name: "schemars"
+        versions: [">=0.9.0"]
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index bc1f19f9b..5eeef0e6d 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -52,6 +52,16 @@ jobs:
     - name: Run tests
       run: cargo test --locked --verbose
 
+  build-test-output:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install Rust
+      uses: dtolnay/rust-toolchain@stable
+    - name: Build the generated clients
+      # We don't apply --locked here as there's no Cargo.lock committed for this crate
+      run: cargo build --manifest-path progenitor-impl/tests/output/Cargo.toml --verbose
+
   build-no-default-features:
     runs-on: ${{ matrix.os }}
     strategy:
diff --git a/progenitor-impl/tests/output/Cargo.toml b/progenitor-impl/tests/output/Cargo.toml
index 37255a091..d9b10b7e8 100644
--- a/progenitor-impl/tests/output/Cargo.toml
+++ b/progenitor-impl/tests/output/Cargo.toml
@@ -3,22 +3,25 @@
 [package]
 name = "test-output"
 version = "0.1.0"
-edition = "2024"
+# typify uses `gen` as a name for parameters of the `JsonSchema` impls it emits.
+# `gen` is a reserved word in Rust 2024, so generated code that derives `schemars::JsonSchema`
+# only parses under an earlier edition.
+edition = "2021"
 rust-version = "1.85"
 license = "MPL-2.0"
 
 [dependencies]
 anyhow = "1.0"
-base64 = "0.21"
+base64 = "0.23"
 chrono = { version = "0.4", features = ["serde"] }
 clap = { version = "4", features = ["string"] }
 futures = "0.3"
-httpmock = "0.7"
+httpmock = "0.8"
 progenitor-client = { path = "../../../progenitor-client" }
-rand = { version = "0.8", features = ["serde1"] }
+rand = { version = "0.10", features = ["serde"] }
 regex = "1.10"
-regress = "0.7"
-reqwest = "0.12"
+regress = "0.12"
+reqwest = "0.13"
 schemars = { version = "0.8", features = ["chrono", "uuid1"] }
 serde = { features = ["derive"], version = "1" }
 serde_json = "1"
diff --git a/progenitor-impl/tests/output/src/lib.rs b/progenitor-impl/tests/output/src/lib.rs
index 1bb9e9564..4e3e426aa 100644
--- a/progenitor-impl/tests/output/src/lib.rs
+++ b/progenitor-impl/tests/output/src/lib.rs
@@ -32,3 +32,23 @@ pub mod test_default_params_builder;
 pub mod test_default_params_positional;
 pub mod test_freeform_response;
 pub mod test_renamed_parameters;
+
+// progenitor emits `clap::value_parser!(T)` for every argument, and clap
+// infers the parser from the traits the type implements. `GetThingOrThingsId`
+// implements none that clap accepts, so we, as the consumer, supply the
+// parser through `ValueParserFactory`, which is what the CLI generator asks a
+// consumer to do.
+impl ::clap::builder::ValueParserFactory for buildomat_builder::types::GetThingOrThingsId {
+    type Parser = ::clap::builder::MapValueParser<
+        ::clap::builder::StringValueParser,
+        fn(String) -> buildomat_builder::types::GetThingOrThingsId,
+    >;
+
+    fn value_parser() -> Self::Parser {
+        ::clap::builder::TypedValueParser::map(
+            ::clap::builder::StringValueParser::new(),
+            buildomat_builder::types::GetThingOrThingsId::String
+                as fn(String) -> buildomat_builder::types::GetThingOrThingsId,
+        )
+    }
+}