diff --git a/.formatter.exs b/.formatter.exs
index 935d310..1371f49 100644
--- a/.formatter.exs
+++ b/.formatter.exs
@@ -1,5 +1,5 @@
 # Used by "mix format"
 [
   inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"],
-  plugins: [Styler]
+  plugins: [DoctestFormatter, Styler]
 ]
diff --git a/lib/mix/tasks/mix_dependency_submission.ex b/lib/mix/tasks/mix_dependency_submission.ex
index f1914e2..d23043b 100644
--- a/lib/mix/tasks/mix_dependency_submission.ex
+++ b/lib/mix/tasks/mix_dependency_submission.ex
@@ -3,7 +3,12 @@ if Mix.env() == :dev do
 
   defmodule Mix.Tasks.MixDependencySubmission do
     @shortdoc "Run mix_depdendency_submission"
-    @moduledoc @shortdoc
+    @moduledoc """
+    #{@shortdoc}
+
+    Only intented for development purposes. Use the burrito binary for
+    production.
+    """
 
     use Mix.Task
 
@@ -11,6 +16,7 @@ if Mix.env() == :dev do
 
     @requirements ["app.start"]
 
+    @doc false
     @impl Mix.Task
     def run(args) do
       Submit.run(args)
diff --git a/lib/mix_dependency_submission.ex b/lib/mix_dependency_submission.ex
index 31fe62c..3c003e9 100644
--- a/lib/mix_dependency_submission.ex
+++ b/lib/mix_dependency_submission.ex
@@ -1,11 +1,94 @@
 defmodule MixDependencySubmission do
-  @moduledoc false
+  @moduledoc """
+  Builds the dependency submission payload from one or more Mix projects.
+
+  Responsible for collecting dependency data, resolving manifests, and
+  assembling the top-level submission struct to be sent to GitHub.
+
+  See https://docs.github.com/en/rest/dependency-graph/dependency-submission?apiVersion=2022-11-28#create-a-snapshot-of-dependencies-for-a-repository
+
+  > #### API Interface {: .warning}
+  > This project is **not a library** and is intended **only** for use as a
+  > GitHub Action. All modules, functions, and types are considered internal and
+  > may change at any time without notice.
+  >
+  > If you're looking to integrate this functionality into your own tooling, open
+  > an issue to discuss the use case, but do not rely on this as a stable library
+  > interface.
+
+  """
 
   alias MixDependencySubmission.Fetcher
   alias MixDependencySubmission.Submission
   alias MixDependencySubmission.Submission.Manifest
   alias MixDependencySubmission.Util
 
+  @doc """
+  Builds a new `MixDependencySubmission.Submission` from a set of project
+  options.
+
+  Finds nested Mix projects (unless ignored), resolves dependencies,
+  and prepares the manifest payload.
+
+  ## Examples
+
+      iex> MixDependencySubmission.submission(
+      ...>   github_job_id: "job123",
+      ...>   github_workflow: "ci.yml",
+      ...>   sha: "sha",
+      ...>   ref: "refs/heads/main",
+      ...>   project_path: ".",
+      ...>   install_deps?: false,
+      ...>   ignore: []
+      ...> )
+      %MixDependencySubmission.Submission{
+        version: 0,
+        job: %MixDependencySubmission.Submission.Job{
+          id: "job123",
+          correlator: "ci.yml job123",
+          html_url: nil
+        },
+        sha: "sha",
+        ref: "refs/heads/main",
+        detector: %MixDependencySubmission.Submission.Detector{
+          name: "mix_dependency_submission",
+          version: %Version{major: 1, minor: 0, patch: 0, pre: ["beta", 8]},
+          url: %URI{
+            scheme: "https",
+            userinfo: nil,
+            host: "github.com",
+            port: 443,
+            path: "/erlef/mix-dependency-submission",
+            query: nil,
+            fragment: nil
+          }
+        },
+        scanned: ~U[2025-04-19 10:15:11.656801Z],
+        metadata: %{},
+        manifests: %{
+          "mix.exs" => %MixDependencySubmission.Submission.Manifest{
+            name: "mix.exs",
+            file: %MixDependencySubmission.Submission.Manifest.File{
+              source_location: "mix.exs"
+            },
+            metadata: %{},
+            resolved: %{
+              "expo" => %MixDependencySubmission.Submission.Manifest.Dependency{
+                package_url:
+                  Purl.parse!(
+                    "pkg:github/elixir-gettext/expo@2ae85019d62288001bdc4a949d65bf650beee315"
+                  ),
+                metadata: %{},
+                relationship: :direct,
+                scope: :runtime,
+                dependencies: []
+              }
+            }
+          }
+        }
+      }
+
+  """
   @spec submission(
           options :: [
             {:github_job_id, String.t()}
@@ -33,7 +116,9 @@ defmodule MixDependencySubmission do
       options[:project_path]
       |> find_mix_projects(options[:ignore] || [], options[:paths_relative_to])
       |> Map.new(fn project_path ->
-        manifest = manifest(project_path, Keyword.take(options, [:paths_relative_to, :install_deps?]))
+        manifest =
+          manifest(project_path, Keyword.take(options, [:paths_relative_to, :install_deps?]))
+
         {manifest.file.source_location, manifest}
       end)
 
@@ -46,7 +131,15 @@ defmodule MixDependencySubmission do
     })
   end
 
-  @spec manifest(project_path :: Path.t(), options :: [{:paths_relative_to, Path.t()} | {:install_deps?, boolean()}]) ::
+  @doc """
+  Resolves the dependency manifest for a single Mix project.
+
+  Optionally installs dependencies beforehand if `install_deps?` is true.
+  """
+  @spec manifest(
+          project_path :: Path.t(),
+          options :: [{:paths_relative_to, Path.t()} | {:install_deps?, boolean()}]
+        ) ::
           Manifest.t()
   def manifest(project_path, options) do
     Util.in_project(project_path, fn _mix_module ->
@@ -58,7 +151,11 @@ defmodule MixDependencySubmission do
     end)
   end
 
-  @spec find_mix_projects(project_path :: Path.t(), ignore :: [Path.t()], paths_relative_to :: Path.t()) :: [Path.t()]
+  @spec find_mix_projects(
+          project_path :: Path.t(),
+          ignore :: [Path.t()],
+          paths_relative_to :: Path.t()
+        ) :: [Path.t()]
   defp find_mix_projects(project_path, ignore, paths_relative_to) do
     ignore = Enum.map(ignore, &Path.expand(&1, paths_relative_to))
 
@@ -102,6 +199,7 @@ defmodule MixDependencySubmission do
     }
   end
 
-  @spec drop_empty(map :: %{key => value | nil}) :: %{key => value} when key: term(), value: term()
+  @spec drop_empty(map :: %{key => value | nil}) :: %{key => value}
+        when key: term(), value: term()
   defp drop_empty(map), do: map |> Enum.reject(fn {_key, value} -> value in [nil, ""] end) |> Map.new()
 end
diff --git a/lib/mix_dependency_submission/api_client.ex b/lib/mix_dependency_submission/api_client.ex
index 385b897..05fdc16 100644
--- a/lib/mix_dependency_submission/api_client.ex
+++ b/lib/mix_dependency_submission/api_client.ex
@@ -1,7 +1,44 @@
 defmodule MixDependencySubmission.ApiClient do
-  @moduledoc false
+  @moduledoc """
+  Handles submission of the dependency snapshot to the GitHub Dependency Submission API.
+  """
+
   alias MixDependencySubmission.Submission
 
+  @doc """
+  Submits a dependency snapshot to the GitHub API.
+
+  Returns `{:ok, response}` if the submission was accepted, or
+  `{:error, {:unexpected_response, response}}` for other HTTP status codes.
+
+  ## Examples
+
+      iex> submission = %MixDependencySubmission.Submission{
+      ...>   version: 0,
+      ...>   job: %MixDependencySubmission.Submission.Job{
+      ...>     id: "job123",
+      ...>     correlator: "workflow job123"
+      ...>   },
+      ...>   sha: String.duplicate("a", 40),
+      ...>   ref: "refs/heads/main",
+      ...>   detector: %MixDependencySubmission.Submission.Detector{
+      ...>     name: "example",
+      ...>     version: Version.parse!("1.0.0"),
+      ...>     url: URI.parse("https://example.com")
+      ...>   },
+      ...>   scanned: DateTime.utc_now(),
+      ...>   manifests: %{}
+      ...> }
+      ...> 
+      ...> {:ok, %Req.Response{} = response} =
+      ...>   MixDependencySubmission.ApiClient.submit(
+      ...>     submission,
+      ...>     "https://api.github.com",
+      ...>     "owner/repo",
+      ...>     "ghp_exampletoken"
+      ...>   )
+
+  """
   @spec submit(
           submission :: Submission.t(),
           github_api_url :: String.t(),
diff --git a/lib/mix_dependency_submission/cli.ex b/lib/mix_dependency_submission/cli.ex
index bfa6f56..6d5a2b3 100644
--- a/lib/mix_dependency_submission/cli.ex
+++ b/lib/mix_dependency_submission/cli.ex
@@ -1,9 +1,29 @@
 defmodule MixDependencySubmission.CLI do
-  @moduledoc false
+  @moduledoc """
+  Handles parsing of CLI arguments using `Optimus`.
+
+  Used to configure and validate inputs for submitting a dependency snapshot.
+  """
+
   @app Mix.Project.config()[:app]
   @description Mix.Project.config()[:description]
   @version Mix.Project.config()[:version]
 
+  @doc """
+  Parses CLI arguments and returns the parsed result.
+
+  Raises on invalid input.
+
+  ## Examples
+
+      iex> argv =
+      ...>   ~w[--github-repository org/repo --github-job-id 123 --github-workflow build --sha sha --ref refs/heads/main --github-token ghp_xxx]
+      ...> 
+      ...> result = MixDependencySubmission.CLI.parse!(argv)
+      ...> result.options.github_repository
+      "org/repo"
+
+  """
   @spec parse!([String.t()]) :: Optimus.ParseResult.t()
   def parse!(argv) do
     cli_definition()
diff --git a/lib/mix_dependency_submission/cli/submit.ex b/lib/mix_dependency_submission/cli/submit.ex
index d5c9b81..d0b6be5 100644
--- a/lib/mix_dependency_submission/cli/submit.ex
+++ b/lib/mix_dependency_submission/cli/submit.ex
@@ -1,10 +1,51 @@
 defmodule MixDependencySubmission.CLI.Submit do
-  @moduledoc false
+  @moduledoc """
+  Handles the CLI submit command for Mix Dependency Submission.
+
+  This module parses CLI arguments, builds the dependency submission payload,
+  and sends it to the GitHub Dependency Submission API. It logs relevant details
+  about the submission process and handles success or failure scenarios
+  accordingly.
+  """
+
   alias MixDependencySubmission.ApiClient
   alias MixDependencySubmission.CLI
 
   require Logger
 
+  @doc """
+  Parses command-line arguments and submits the dependency snapshot to the
+  GitHub API.
+
+  This function is intended to be called from the CLI. It:
+
+  - Parses CLI arguments using `Optimus`.
+  - Generates a dependency submission using
+    `MixDependencySubmission.submission/1`.
+  - Logs the resulting submission in pretty-printed JSON.
+  - Sends the submission to GitHub using
+    `MixDependencySubmission.ApiClient.submit/4`.
+  - Logs the response or error and exits with code 0 or 1 accordingly.
+
+  ## Parameters
+
+    - `argv`: A list of command-line argument strings.
+
+  ## Behavior
+
+  This function does not return. It will halt or stop the system depending on
+  the outcome of the submission.
+
+  ## Examples
+
+      iex> MixDependencySubmission.CLI.Submit.run([
+      ...>   "--project-path",
+      ...>   ".",
+      ...>   "--github-repository",
+      ...>   "org/repo"
+      ...> ])
+
+  """
   @spec run(argv :: [String.t()]) :: no_return()
   def run(argv) do
     %Optimus.ParseResult{
diff --git a/lib/mix_dependency_submission/fetcher.ex b/lib/mix_dependency_submission/fetcher.ex
index a0440fa..01f557a 100644
--- a/lib/mix_dependency_submission/fetcher.ex
+++ b/lib/mix_dependency_submission/fetcher.ex
@@ -1,6 +1,14 @@
 defmodule MixDependencySubmission.Fetcher do
   @moduledoc """
-  Behaviour for Manifest Fetchers
+  Defines the behaviour for manifest fetchers and provides an entry point to collect
+  dependency data from multiple sources.
+
+  The built-in fetchers include:
+
+    * `MixDependencySubmission.Fetcher.MixFile` — parses `mix.exs`
+    * `MixDependencySubmission.Fetcher.MixLock` — parses `mix.lock`
+    * `MixDependencySubmission.Fetcher.MixRuntime` — inspects runtime dependency
+      graph
   """
 
   alias MixDependencySubmission.SCM
@@ -20,10 +28,53 @@ defmodule MixDependencySubmission.Fetcher do
           optional(:mix_config) => Keyword.t()
         }
 
+  @doc """
+  Fetches dependencies from a specific source.
+
+  Implementers must return a map of app names to raw dependency data, or `nil`
+  if no data is available.
+
+  This callback is used by the main `MixDependencySubmission.Fetcher.fetch/0`
+  function to gather and merge data from multiple sources like `mix.exs`,
+  `mix.lock`, or the compiled dependency graph.
+
+  ## Example return value
+
+      %{
+        my_dep: %{
+          scm: Mix.SCM.Hex,
+          version: "0.1.0",
+          scope: :runtime,
+          relationship: :direct
+        }
+      }
+
+  Returning `nil` signals that no data could be fetched by the implementation.
+  """
   @callback fetch() :: %{optional(app_name()) => dependency()} | nil
 
   @manifest_fetchers [__MODULE__.MixFile, __MODULE__.MixLock, __MODULE__.MixRuntime]
 
+  @doc """
+  Fetches and merges dependencies from all registered fetchers.
+
+  Returns a map of stringified app names to structured `Dependency` records,
+  ready to be submitted as a manifest.
+
+  ## Examples
+
+      iex> %{
+      ...>   "burrito" => %MixDependencySubmission.Submission.Manifest.Dependency{
+      ...>     package_url: %Purl{type: "hex", name: "burrito"},
+      ...>     metadata: %{},
+      ...>     relationship: :direct,
+      ...>     scope: :runtime,
+      ...>     dependencies: _dependencies
+      ...>   }
+      ...> } = MixDependencySubmission.Fetcher.fetch()
+
+  Note: This test assumes an Elixir project that is currently loaded.
+  """
   @spec fetch() :: %{String.t() => Dependency.t()} | nil
   def fetch do
     @manifest_fetchers
@@ -44,7 +95,9 @@ defmodule MixDependencySubmission.Fetcher do
   @spec merge(app_name(), left :: dependency(), right :: dependency()) :: dependency()
   defp merge(_app, left, right), do: Map.merge(left, right)
 
-  @spec transform_all(dependencies :: %{app_name() => dependency()}) :: %{String.t() => Dependency.t()}
+  @spec transform_all(dependencies :: %{app_name() => dependency()}) :: %{
+          String.t() => Dependency.t()
+        }
   defp transform_all(dependencies) do
     dependencies =
       Map.new(dependencies, fn {app, dependency} ->
@@ -66,7 +119,8 @@ defmodule MixDependencySubmission.Fetcher do
 
   @spec transform(app_name(), dependency()) :: Dependency.t()
   defp transform(app, dependency) do
-    sub_dependencies = Enum.uniq((dependency[:dependencies] || []) ++ lock_dependencies(dependency))
+    sub_dependencies =
+      Enum.uniq((dependency[:dependencies] || []) ++ lock_dependencies(dependency))
 
     metadata =
       %{
@@ -139,6 +193,7 @@ defmodule MixDependencySubmission.Fetcher do
 
   defp lock_dependencies(_dependency), do: []
 
-  @spec drop_empty(map :: %{key => value | nil}) :: %{key => value} when key: term(), value: term()
+  @spec drop_empty(map :: %{key => value | nil}) :: %{key => value}
+        when key: term(), value: term()
   defp drop_empty(map), do: map |> Enum.reject(fn {_key, value} -> value in [nil, ""] end) |> Map.new()
 end
diff --git a/lib/mix_dependency_submission/fetcher/mix_file.ex b/lib/mix_dependency_submission/fetcher/mix_file.ex
index 2b761bc..a8550f4 100644
--- a/lib/mix_dependency_submission/fetcher/mix_file.ex
+++ b/lib/mix_dependency_submission/fetcher/mix_file.ex
@@ -1,12 +1,38 @@
 defmodule MixDependencySubmission.Fetcher.MixFile do
   @moduledoc """
-  Fetch Dependencies from mix.exs directly.
+  A `MixDependencySubmission.Fetcher` implementation that extracts dependencies
+  from the current project's `mix.exs` file.
+
+  This module is responsible for reading and normalizing direct dependencies
+  defined in the project configuration, returning them in a standard format
+  expected by the submission tool.
   """
 
   @behaviour MixDependencySubmission.Fetcher
 
   alias MixDependencySubmission.Fetcher
 
+  @doc """
+  Fetches and normalizes the direct dependencies defined in the `mix.exs` file.
+
+  This implementation reads the project configuration via
+  `Mix.Project.config()[:deps]` and normalizes each dependency entry.
+
+  ## Examples
+
+      iex> %{
+      ...>   burrito: %{
+      ...>     scm: Hex.SCM,
+      ...>     mix_dep: _dep,
+      ...>     relationship: :direct,
+      ...>     scope: :runtime
+      ...>   }
+      ...> } =
+      ...>   MixDependencySubmission.Fetcher.MixFile.fetch()
+
+  Note: This test assumes an Elixir project that is currently loaded with a
+  `mix.exs` file in place.
+  """
   @impl Fetcher
   def fetch do
     Mix.Project.config()[:deps] |> List.wrap() |> Map.new(&normalize_dep/1)
diff --git a/lib/mix_dependency_submission/fetcher/mix_lock.ex b/lib/mix_dependency_submission/fetcher/mix_lock.ex
index cc3cd08..842558d 100644
--- a/lib/mix_dependency_submission/fetcher/mix_lock.ex
+++ b/lib/mix_dependency_submission/fetcher/mix_lock.ex
@@ -1,6 +1,9 @@
 defmodule MixDependencySubmission.Fetcher.MixLock do
   @moduledoc """
-  Fetch Dependencies from mix.lock directly.
+  Fetches dependencies from the `mix.lock` file.
+
+  This module implements the `MixDependencySubmission.Fetcher` behaviour to extract
+  locked dependencies and convert them into the expected internal format.
   """
 
   @behaviour MixDependencySubmission.Fetcher
@@ -9,6 +12,19 @@ defmodule MixDependencySubmission.Fetcher.MixLock do
 
   require Logger
 
+  @doc """
+  Reads and normalizes locked dependencies from the `mix.lock` file.
+
+  Returns `nil` if the lockfile doesn't exist.
+
+  ## Examples
+
+      iex> %{burrito: %{scm: Hex.SCM, mix_lock: [:hex, :burrito | _]}} =
+      ...>   MixDependencySubmission.Fetcher.MixLock.fetch()
+
+  Note: This test assumes an Elixir project that is currently loaded with a
+  `mix.lock` file in place.
+  """
   @impl Fetcher
   def fetch do
     lockfile_name = Mix.Project.config()[:lockfile]
@@ -32,11 +48,13 @@ defmodule MixDependencySubmission.Fetcher.MixLock do
     else
       {:error, reason} ->
         Logger.warning("Failed to read lockfile #{lockfile}, reason: #{inspect(reason, pretty: true)}")
+
         %{}
     end
   end
 
-  @spec normalize_dep(dep :: {Fetcher.app_name(), tuple()}) :: {Fetcher.app_name(), Fetcher.dependency()}
+  @spec normalize_dep(dep :: {Fetcher.app_name(), tuple()}) ::
+          {Fetcher.app_name(), Fetcher.dependency()}
   defp normalize_dep({app, lock} = _dep) do
     scm = Enum.find(Mix.SCM.available(), & &1.format_lock(lock: lock))
 
diff --git a/lib/mix_dependency_submission/fetcher/mix_runtime.ex b/lib/mix_dependency_submission/fetcher/mix_runtime.ex
index d8b77b2..3b75251 100644
--- a/lib/mix_dependency_submission/fetcher/mix_runtime.ex
+++ b/lib/mix_dependency_submission/fetcher/mix_runtime.ex
@@ -1,12 +1,38 @@
 defmodule MixDependencySubmission.Fetcher.MixRuntime do
   @moduledoc """
-  Fetch Dependencies from Mix Runtime.
+  Fetches dependencies from the compiled Mix project at runtime.
+
+  This fetcher uses `Mix.Project.deps_tree/1` and related project metadata to
+  collect runtime dependency information including versions, SCMs, and
+  relationships.
   """
 
   @behaviour MixDependencySubmission.Fetcher
 
   alias MixDependencySubmission.Fetcher
 
+  @doc """
+  Fetches all runtime dependencies from the current Mix project.
+
+  Includes both direct and indirect dependencies as resolved from the dependency
+  tree at runtime.
+
+  ## Examples
+
+      iex> %{
+      ...>   burrito: %{
+      ...>     scm: Hex.SCM,
+      ...>     dependencies: [:jason, :req, :typed_struct],
+      ...>     mix_config: _config,
+      ...>     relationship: :direct,
+      ...>     scope: :runtime,
+      ...>     version: _version
+      ...>   }
+      ...> } =
+      ...>   MixDependencySubmission.Fetcher.MixRuntime.fetch()
+
+  Note: This test assumes an Elixir project that is currently loaded.
+  """
   @impl Fetcher
   def fetch do
     root_deps = [depth: 1] |> Mix.Project.deps_tree() |> Map.keys()
@@ -28,7 +54,9 @@ defmodule MixDependencySubmission.Fetcher.MixRuntime do
 
     config =
       if Elixir.File.exists?(dep_path) do
-        Mix.Project.in_project(app, Map.fetch!(deps_paths, app), fn _module -> Mix.Project.config() end)
+        Mix.Project.in_project(app, Map.fetch!(deps_paths, app), fn _module ->
+          Mix.Project.config()
+        end)
       else
         []
       end
diff --git a/lib/mix_dependency_submission/scm.ex b/lib/mix_dependency_submission/scm.ex
index a1d1734..a34caa6 100644
--- a/lib/mix_dependency_submission/scm.ex
+++ b/lib/mix_dependency_submission/scm.ex
@@ -1,11 +1,20 @@
 defmodule MixDependencySubmission.SCM do
-  @moduledoc false
+  @moduledoc """
+  Defines the behavior and helper types for working with source control managers
+  (SCMs) in the Mix dependency submission context.
+
+  SCM implementations are responsible for generating package URLs (`purl`) and
+  extracting dependency metadata from `mix.lock` or `mix.exs`.
+
+  Implementations must live under `MixDependencySubmission.SCM.[NAME]` and match
+  the name of the corresponding module in `Mix.SCM.available/0`.
+  """
 
   @typedoc """
   Lock for the dependency as a list.
 
-  **Always only match the start of the list. The list can be extended to include
-  further contents in the future at the end of the list.**
+  **Always only match the start of the list. The list can be extended in the
+  future.**
 
   ## Examples
 
@@ -30,29 +39,45 @@ defmodule MixDependencySubmission.SCM do
   @type dep() :: {app_name(), requirement :: String.t() | nil, opts :: Keyword.t()}
 
   @doc """
-  Create a package url for the given `dep`.
+  Creates a package URL (`purl`) from a declared dependency.
 
+  Implementations are expected to convert the given Mix dependency (from `mix.exs`)
+  into a `Purl` struct.
   """
   @callback mix_dep_to_purl(dep(), version :: String.t() | nil) :: Purl.t()
 
   @doc """
-  Create a package url for the given `dep`.
-
-  ## Examples
-
-        iex> MixDependencySubmission.SCM.Hex.SCM.mix_dependency_to_package_url(:credo)
-        {:ok, Purl.parse!("pkg:hex/credo@1.7.0")}
-
-        iex> MixDependencySubmission.SCM.Hex.SCM.mix_dependency_to_package_url(:invalid)
-        :error
+  Creates a package URL (`purl`) from a locked dependency.
 
+  This is used when data is available from `mix.lock`.
   """
   @callback mix_lock_to_purl(app :: atom(), lock :: lock()) :: Purl.t()
 
+  @doc """
+  Returns a list of app names representing sub-dependencies found in the lock.
+
+  Only used if the SCM implementation supports this and provides custom logic.
+  """
   @callback mix_lock_deps(lock :: lock()) :: [app_name()]
 
   @optional_callbacks mix_lock_deps: 1, mix_lock_to_purl: 2
 
+  @doc """
+  Returns the module implementing SCM-specific behavior for a given SCM module.
+
+  Looks for a corresponding module under `MixDependencySubmission.SCM.*`.
+
+  Returns `nil` if no implementation exists or the module is not loaded.
+
+  ## Examples
+
+      iex> MixDependencySubmission.SCM.implementation(Mix.SCM.Path)
+      MixDependencySubmission.SCM.Mix.SCM.Path
+
+      iex> MixDependencySubmission.SCM.implementation(Unknown.SCM)
+      nil
+
+  """
   @spec implementation(module()) :: module() | nil
   def implementation(scm) when is_atom(scm) do
     if scm in Mix.SCM.available() do
diff --git a/lib/mix_dependency_submission/scm/hex/scm.ex b/lib/mix_dependency_submission/scm/hex/scm.ex
index 79d5ec6..e668da7 100644
--- a/lib/mix_dependency_submission/scm/hex/scm.ex
+++ b/lib/mix_dependency_submission/scm/hex/scm.ex
@@ -1,10 +1,34 @@
 defmodule MixDependencySubmission.SCM.Hex.SCM do
-  @moduledoc false
+  @moduledoc """
+  SCM implementation for Hex packages.
+
+  Handles the conversion of Hex dependencies into `purl` format and extraction
+  of dependency information from `mix.exs` and `mix.lock`.
+  """
 
   @behaviour MixDependencySubmission.SCM
 
   alias MixDependencySubmission.SCM
 
+  @doc """
+  Creates a package URL (`purl`) from a declared Mix dependency (`mix.exs`).
+
+  Attempts to resolve the repository URL and include it as a `qualifier`.
+
+  ## Examples
+
+      iex> MixDependencySubmission.SCM.Hex.SCM.mix_dep_to_purl(
+      ...>   {:jason, "~> 1.0", [hex: :jason, repo: "hexpm"]},
+      ...>   "1.4.0"
+      ...> )
+      %Purl{
+        type: "hex",
+        namespace: [],
+        name: "jason",
+        version: "1.4.0",
+        qualifiers: %{}
+      }
+  """
   @impl SCM
   def mix_dep_to_purl({_app, requirement, opts}, version) do
     qualifiers =
@@ -22,9 +46,45 @@ defmodule MixDependencySubmission.SCM.Hex.SCM do
     })
   end
 
+  @doc """
+  Creates a package URL (`purl`) from a locked dependency (`mix.lock` entry).
+
+  Attempts to include the repository URL as a `qualifier`, if resolvable.
+
+  ## Examples
+
+      iex> lock = [
+      ...>   :hex,
+      ...>   :jason,
+      ...>   "1.4.0",
+      ...>   "checksum",
+      ...>   [:mix],
+      ...>   [],
+      ...>   "hexpm",
+      ...>   "checksum"
+      ...> ]
+      ...> 
+      ...> MixDependencySubmission.SCM.Hex.SCM.mix_lock_to_purl(:jason, lock)
+      %Purl{
+        type: "hex",
+        namespace: [],
+        name: "jason",
+        version: "1.4.0",
+        qualifiers: %{}
+      }
+  """
   @impl SCM
   def mix_lock_to_purl(_app, lock) do
-    [:hex, package_name, version, _inner_checksum, _managers, _deps, repo, _outer_checksum | _rest] = lock
+    [
+      :hex,
+      package_name,
+      version,
+      _inner_checksum,
+      _managers,
+      _deps,
+      repo,
+      _outer_checksum | _rest
+    ] = lock
 
     qualifiers =
       case repository_url(repo) do
@@ -41,9 +101,40 @@ defmodule MixDependencySubmission.SCM.Hex.SCM do
     })
   end
 
+  @doc """
+  Returns the list of app names that are dependencies of the given locked dependency.
+
+  ## Examples
+
+      iex> lock = [
+      ...>   :hex,
+      ...>   :my_app,
+      ...>   "0.1.0",
+      ...>   "checksum",
+      ...>   [:mix],
+      ...>   [
+      ...>     {:dep_a, "~> 0.1.0", [hex: :dep_a]},
+      ...>     {:dep_b, "~> 0.2.0", [hex: :dep_b]}
+      ...>   ],
+      ...>   "hexpm",
+      ...>   "checksum"
+      ...> ]
+      ...> 
+      ...> MixDependencySubmission.SCM.Hex.SCM.mix_lock_deps(lock)
+      [:dep_a, :dep_b]
+  """
   @impl SCM
   def mix_lock_deps(lock) do
-    [:hex, _package_name, _version, _inner_checksum, _managers, deps, _repo, _outer_checksum | _rest] = lock
+    [
+      :hex,
+      _package_name,
+      _version,
+      _inner_checksum,
+      _managers,
+      deps,
+      _repo,
+      _outer_checksum | _rest
+    ] = lock
 
     Enum.map(deps, fn {app, _requirement, _opts} -> app end)
   end
diff --git a/lib/mix_dependency_submission/scm/mix/scm/git.ex b/lib/mix_dependency_submission/scm/mix/scm/git.ex
index aad1e7c..97188fb 100644
--- a/lib/mix_dependency_submission/scm/mix/scm/git.ex
+++ b/lib/mix_dependency_submission/scm/mix/scm/git.ex
@@ -1,10 +1,36 @@
 defmodule MixDependencySubmission.SCM.Mix.SCM.Git do
-  @moduledoc false
+  @moduledoc """
+  SCM implementation for Git-based Mix dependencies.
+
+  Handles conversion of Git dependencies declared in `mix.exs` or found in
+  `mix.lock` into package URLs (purl). Falls back to a generic purl format if
+  the repository URL does not represent a specific purl type like `pkg:github`.
+  """
 
   @behaviour MixDependencySubmission.SCM
 
   alias MixDependencySubmission.SCM
 
+  @doc """
+  Creates a package URL (`purl`) from a Git-based Mix dependency.
+
+  Attempts to infer the version from `:ref`, `:branch`, or `:tag`, or falls back
+  to the requirement.
+
+  ## Examples
+
+      iex> MixDependencySubmission.SCM.Mix.SCM.Git.mix_dep_to_purl(
+      ...>   {:my_app, nil, [git: "https://github.com/example/my_app.git", tag: "v1.0.0"]},
+      ...>   nil
+      ...> )
+      %Purl{
+        type: "github",
+        name: "my_app",
+        namespace: ["example"],
+        version: "v1.0.0"
+      }
+
+  """
   @impl SCM
   def mix_dep_to_purl({app, requirement, opts}, version) do
     version = version || opts[:ref] || opts[:branch] || opts[:tag] || requirement
@@ -23,6 +49,25 @@ defmodule MixDependencySubmission.SCM.Mix.SCM.Git do
     end
   end
 
+  @doc """
+  Creates a package URL (`purl`) from a Git-based `mix.lock` entry.
+
+  Uses the repository URL and Git revision as the version.
+
+  ## Examples
+
+      iex> MixDependencySubmission.SCM.Mix.SCM.Git.mix_lock_to_purl(
+      ...>   :my_app,
+      ...>   [:git, "https://github.com/example/my_app.git", "abc123"]
+      ...> )
+      %Purl{
+        type: "github",
+        name: "my_app",
+        namespace: ["example"],
+        version: "abc123"
+      }
+
+  """
   @impl SCM
   def mix_lock_to_purl(app, lock) do
     [:git, repo_url, revision | _rest] = lock
diff --git a/lib/mix_dependency_submission/scm/mix/scm/path.ex b/lib/mix_dependency_submission/scm/mix/scm/path.ex
index 94d4e2e..9c4432b 100644
--- a/lib/mix_dependency_submission/scm/mix/scm/path.ex
+++ b/lib/mix_dependency_submission/scm/mix/scm/path.ex
@@ -1,24 +1,49 @@
 defmodule MixDependencySubmission.SCM.Mix.SCM.Path do
-  @moduledoc false
+  @moduledoc """
+  SCM implementation for path-based Mix dependencies.
+
+  Generates a generic `purl` for dependencies declared with `:path` in
+  `mix.exs`.
+  """
 
   @behaviour MixDependencySubmission.SCM
 
   alias MixDependencySubmission.SCM
 
+  @doc """
+  Creates a generic package URL (`purl`) from a path-based Mix dependency.
+
+  Uses the `requirement` from `mix.exs`, or falls back to the version if available.
+
+  ## Examples
+
+      iex> MixDependencySubmission.SCM.Mix.SCM.Path.mix_dep_to_purl(
+      ...>   {:my_dep, "~> 0.1.0", path: "deps/my_dep"},
+      ...>   nil
+      ...> )
+      %Purl{
+        type: "generic",
+        name: "my_dep",
+        version: "~> 0.1.0"
+      }
+
+      iex> MixDependencySubmission.SCM.Mix.SCM.Path.mix_dep_to_purl(
+      ...>   {:my_dep, nil, path: "deps/my_dep"},
+      ...>   "0.1.0"
+      ...> )
+      %Purl{
+        type: "generic",
+        name: "my_dep",
+        version: "0.1.0"
+      }
+
+  """
   @impl SCM
-  def mix_dep_to_purl({app, requirement, opts}, version) do
-    version = version || opts[:ref] || opts[:branch] || opts[:tag] || requirement
-
-    case Purl.from_resource_uri(opts[:git]) do
-      {:ok, purl} ->
-        %{purl | version: version}
-
-      :error ->
-        Purl.new!(%Purl{
-          type: "generic",
-          name: Atom.to_string(app),
-          version: version
-        })
-    end
+  def mix_dep_to_purl({app, requirement, _opts}, version) do
+    Purl.new!(%Purl{
+      type: "generic",
+      name: Atom.to_string(app),
+      version: requirement || version
+    })
   end
 end
diff --git a/lib/mix_dependency_submission/submission.ex b/lib/mix_dependency_submission/submission.ex
index 100244e..fbf4f99 100644
--- a/lib/mix_dependency_submission/submission.ex
+++ b/lib/mix_dependency_submission/submission.ex
@@ -1,5 +1,9 @@
 defmodule MixDependencySubmission.Submission do
-  @moduledoc false
+  @moduledoc """
+  Represents the top-level dependency submission payload.
+
+  See https://docs.github.com/en/rest/dependency-graph/dependency-submission?apiVersion=2022-11-28#create-a-snapshot-of-dependencies-for-a-repository
+  """
 
   alias MixDependencySubmission.Submission.Detector
   alias MixDependencySubmission.Submission.Job
@@ -31,17 +35,62 @@ defmodule MixDependencySubmission.Submission do
     url: URI.new!(@url)
   }
 
+  @doc """
+  Creates a new dependency submission struct from GitHub-related metadata and resolved manifests.
+
+  ## Examples
+
+      iex> MixDependencySubmission.Submission.new(%{
+      ...>   github_job_id: "job123",
+      ...>   github_workflow: "build.yml",
+      ...>   ref: "refs/heads/main",
+      ...>   sha: "sha",
+      ...>   manifests: %{},
+      ...>   scanned: ~U[2025-04-19 10:05:38.170646Z]
+      ...> })
+      %MixDependencySubmission.Submission{
+        version: 0,
+        job: %MixDependencySubmission.Submission.Job{
+          id: "job123",
+          correlator: "build.yml job123",
+          html_url: nil
+        },
+        sha: "sha",
+        ref: "refs/heads/main",
+        detector: %MixDependencySubmission.Submission.Detector{
+          name: "mix_dependency_submission",
+          version: #{inspect(Version.parse!(@version))},
+          url: %URI{
+            scheme: "https",
+            userinfo: nil,
+            host: "github.com",
+            port: 443,
+            path: "/erlef/mix-dependency-submission",
+            query: nil,
+            fragment: nil
+          }
+        },
+        scanned: ~U[2025-04-19 10:05:38.170646Z],
+        metadata: %{},
+        manifests: %{}
+      }
+
+  """
   @spec new(
           options :: %{
-            github_job_id: String.t(),
-            github_workflow: String.t(),
-            ref: String.t(),
-            sha: String.t(),
-            manifests: manifests()
+            required(:github_job_id) => String.t(),
+            required(:github_workflow) => String.t(),
+            required(:ref) => String.t(),
+            required(:sha) => String.t(),
+            required(:manifests) => manifests(),
+            optional(:scanned) => DateTime.t()
           }
         ) :: t()
 
-  def new(%{github_job_id: github_job_id, github_workflow: github_workflow, sha: sha, ref: ref, manifests: manifests}) do
+  def new(
+        %{github_job_id: github_job_id, github_workflow: github_workflow, sha: sha, ref: ref, manifests: manifests} =
+          options
+      ) do
     %__MODULE__{
       version: 0,
       job: %Job{
@@ -52,7 +101,7 @@ defmodule MixDependencySubmission.Submission do
       ref: ref,
       detector: @detector,
       metadata: %{},
-      scanned: DateTime.utc_now(),
+      scanned: options[:scanned] || DateTime.utc_now(),
       manifests: manifests
     }
   end
diff --git a/lib/mix_dependency_submission/submission/detector.ex b/lib/mix_dependency_submission/submission/detector.ex
index 8b400ed..fc1e747 100644
--- a/lib/mix_dependency_submission/submission/detector.ex
+++ b/lib/mix_dependency_submission/submission/detector.ex
@@ -1,5 +1,9 @@
 defmodule MixDependencySubmission.Submission.Detector do
-  @moduledoc false
+  @moduledoc """
+  Represents the detector entry in the submission manifest.
+
+  See https://docs.github.com/en/rest/dependency-graph/dependency-submission?apiVersion=2022-11-28#create-a-snapshot-of-dependencies-for-a-repository
+  """
 
   @type t :: %__MODULE__{
           name: String.t(),
diff --git a/lib/mix_dependency_submission/submission/job.ex b/lib/mix_dependency_submission/submission/job.ex
index caa111f..fcd8df7 100644
--- a/lib/mix_dependency_submission/submission/job.ex
+++ b/lib/mix_dependency_submission/submission/job.ex
@@ -1,5 +1,9 @@
 defmodule MixDependencySubmission.Submission.Job do
-  @moduledoc false
+  @moduledoc """
+  Represents the job entry in the submission manifest.
+
+  See https://docs.github.com/en/rest/dependency-graph/dependency-submission?apiVersion=2022-11-28#create-a-snapshot-of-dependencies-for-a-repository
+  """
 
   @type t :: %__MODULE__{
           id: String.t(),
diff --git a/lib/mix_dependency_submission/submission/manifest.ex b/lib/mix_dependency_submission/submission/manifest.ex
index 388b2dd..709df64 100644
--- a/lib/mix_dependency_submission/submission/manifest.ex
+++ b/lib/mix_dependency_submission/submission/manifest.ex
@@ -1,5 +1,9 @@
 defmodule MixDependencySubmission.Submission.Manifest do
-  @moduledoc false
+  @moduledoc """
+  Represents a manifest entry in the submission payload.
+
+  See https://docs.github.com/en/rest/dependency-graph/dependency-submission?apiVersion=2022-11-28#create-a-snapshot-of-dependencies-for-a-repository
+  """
 
   alias MixDependencySubmission.Submission.Manifest.Dependency
   alias MixDependencySubmission.Submission.Manifest.File
diff --git a/lib/mix_dependency_submission/submission/manifest/dependency.ex b/lib/mix_dependency_submission/submission/manifest/dependency.ex
index c64d95b..cadbc05 100644
--- a/lib/mix_dependency_submission/submission/manifest/dependency.ex
+++ b/lib/mix_dependency_submission/submission/manifest/dependency.ex
@@ -1,5 +1,12 @@
 defmodule MixDependencySubmission.Submission.Manifest.Dependency do
-  @moduledoc false
+  @moduledoc """
+  Represents a dependency entry in the submission manifest.
+
+  Used to describe individual dependencies with metadata, scope, and
+  relationship information, including any nested dependencies via `purl`s.
+
+  See https://docs.github.com/en/rest/dependency-graph/dependency-submission?apiVersion=2022-11-28#create-a-snapshot-of-dependencies-for-a-repository
+  """
 
   @type relationship() :: :direct | :indirect
   @type scope() :: :runtime | :development
diff --git a/lib/mix_dependency_submission/submission/manifest/file.ex b/lib/mix_dependency_submission/submission/manifest/file.ex
index af9652e..781392f 100644
--- a/lib/mix_dependency_submission/submission/manifest/file.ex
+++ b/lib/mix_dependency_submission/submission/manifest/file.ex
@@ -1,5 +1,9 @@
 defmodule MixDependencySubmission.Submission.Manifest.File do
-  @moduledoc false
+  @moduledoc """
+  Represents a file entry in the submission manifest.
+
+  See https://docs.github.com/en/rest/dependency-graph/dependency-submission?apiVersion=2022-11-28#create-a-snapshot-of-dependencies-for-a-repository
+  """
 
   @type t :: %__MODULE__{
           source_location: Path.t() | nil
diff --git a/lib/mix_dependency_submission/util.ex b/lib/mix_dependency_submission/util.ex
index 30dde20..81d4b13 100644
--- a/lib/mix_dependency_submission/util.ex
+++ b/lib/mix_dependency_submission/util.ex
@@ -1,7 +1,8 @@
 defmodule MixDependencySubmission.Util do
   @moduledoc false
 
-  @spec in_project(path :: Path.t(), fun :: (module() | nil -> result)) :: result when result: term()
+  @spec in_project(path :: Path.t(), fun :: (module() | nil -> result)) :: result
+        when result: term()
   def in_project(path, fun) do
     setup_context(fn ->
       path
diff --git a/mix.exs b/mix.exs
index 1eb7abd..d05e84c 100644
--- a/mix.exs
+++ b/mix.exs
@@ -61,17 +61,20 @@ defmodule MixDependencySubmission.MixProject do
       source_url: @source_url,
       source_ref: "v" <> @version,
       main: "readme",
-      extras: ["README.md"]
+      extras: ["README.md"],
+      nest_modules_by_prefix: [MixDependencySubmission]
     ]
   end
 
   defp deps do
+    # styler:sort
     [
       {:burrito, "~> 1.0"},
       {:credo, "~> 1.0", only: [:dev], runtime: false},
       {:dialyxir, "~> 1.0", only: [:dev], runtime: false},
-      {:excoveralls, "~> 0.5", only: [:test], runtime: false},
+      {:doctest_formatter, "~> 0.3.1", runtime: false},
       {:ex_doc, ">= 0.0.0", only: [:dev], runtime: false},
+      {:excoveralls, "~> 0.5", only: [:test], runtime: false},
       {:hex, github: "hexpm/hex", runtime: false},
       {:jason, "~> 1.4"},
       {:optimus, "~> 0.2"},
diff --git a/mix.lock b/mix.lock
index 0e82886..f8b884c 100644
--- a/mix.lock
+++ b/mix.lock
@@ -3,6 +3,7 @@
   "burrito": {:hex, :burrito, "1.3.0", "4be8504185250756ff4a8770d0c0d91dbfe518d2faa5f1888f13b00540028c59", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:req, ">= 0.5.0", [hex: :req, repo: "hexpm", optional: false]}, {:typed_struct, "~> 0.2.0 or ~> 0.3.0", [hex: :typed_struct, repo: "hexpm", optional: false]}], "hexpm", "a53f6bc0644bfd998164d68714c9af04291c220f5f7d0c90cb9616780cc60165"},
   "credo": {:hex, :credo, "1.7.12", "9e3c20463de4b5f3f23721527fcaf16722ec815e70ff6c60b86412c695d426c1", [:mix], [{:bunt, "~> 0.2.1 or ~> 1.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "8493d45c656c5427d9c729235b99d498bd133421f3e0a683e5c1b561471291e5"},
   "dialyxir": {:hex, :dialyxir, "1.4.5", "ca1571ac18e0f88d4ab245f0b60fa31ff1b12cbae2b11bd25d207f865e8ae78a", [:mix], [{:erlex, ">= 0.2.7", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "b0fb08bb8107c750db5c0b324fa2df5ceaa0f9307690ee3c1f6ba5b9eb5d35c3"},
+  "doctest_formatter": {:hex, :doctest_formatter, "0.3.1", "a3fd87c1f75e8a78e7737ec4a4494800ddda705998a59320b87fe4c59c030794", [:mix], [], "hexpm", "3c092540d8b73ffc526a92daa2dc2ecd50714f14325eeacbc7b4e790f890443a"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.44", "f20830dd6b5c77afe2b063777ddbbff09f9759396500cdbe7523efd58d7a339c", [:mix], [], "hexpm", "4778ac752b4701a5599215f7030989c989ffdc4f6df457c5f36938cc2d2a2750"},
   "erlex": {:hex, :erlex, "0.2.7", "810e8725f96ab74d17aac676e748627a07bc87eb950d2b83acd29dc047a30595", [:mix], [], "hexpm", "3ed95f79d1a844c3f6bf0cea61e0d5612a42ce56da9c03f01df538685365efb0"},
   "ex_doc": {:hex, :ex_doc, "0.37.3", "f7816881a443cd77872b7d6118e8a55f547f49903aef8747dbcb345a75b462f9", [:mix], [{:earmark_parser, "~> 1.4.42", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "e6aebca7156e7c29b5da4daa17f6361205b2ae5f26e5c7d8ca0d3f7e18972233"},
diff --git a/test/mix_dependency_submission/api_client_test.exs b/test/mix_dependency_submission/api_client_test.exs
index d2118c6..17c39c5 100644
--- a/test/mix_dependency_submission/api_client_test.exs
+++ b/test/mix_dependency_submission/api_client_test.exs
@@ -4,6 +4,8 @@ defmodule MixDependencySubmission.ApiClientTest do
   alias MixDependencySubmission.ApiClient
   alias MixDependencySubmission.Submission
 
+  doctest ApiClient, except: [submit: 4]
+
   describe inspect(&ApiClient.submit/4) do
     test "sends correct request" do
       Req.Test.stub(ApiClient, fn conn ->
diff --git a/test/mix_dependency_submission/cli_test.exs b/test/mix_dependency_submission/cli_test.exs
new file mode 100644
index 0000000..aaa5e6e
--- /dev/null
+++ b/test/mix_dependency_submission/cli_test.exs
@@ -0,0 +1,7 @@
+defmodule MixDependencySubmission.CLITest do
+  use ExUnit.Case, async: true
+
+  alias MixDependencySubmission.CLI
+
+  doctest CLI
+end
diff --git a/test/mix_dependency_submission/fetcher/mix_file_test.exs b/test/mix_dependency_submission/fetcher/mix_file_test.exs
index 0f69e12..46e9a87 100644
--- a/test/mix_dependency_submission/fetcher/mix_file_test.exs
+++ b/test/mix_dependency_submission/fetcher/mix_file_test.exs
@@ -4,7 +4,7 @@ defmodule MixDependencySubmission.Fetcher.MixFileTest do
   alias MixDependencySubmission.Fetcher.MixFile
   alias MixDependencySubmission.Util
 
-  doctest MixDependencySubmission
+  doctest MixFile
 
   describe inspect(&MixFile.fetch/1) do
     @tag :tmp_dir
diff --git a/test/mix_dependency_submission/fetcher/mix_lock_test.exs b/test/mix_dependency_submission/fetcher/mix_lock_test.exs
index 1706d0c..ebccfaf 100644
--- a/test/mix_dependency_submission/fetcher/mix_lock_test.exs
+++ b/test/mix_dependency_submission/fetcher/mix_lock_test.exs
@@ -4,7 +4,7 @@ defmodule MixDependencySubmission.Fetcher.MixLockTest do
   alias MixDependencySubmission.Fetcher.MixLock
   alias MixDependencySubmission.Util
 
-  doctest MixDependencySubmission
+  doctest MixLock
 
   describe inspect(&MixLock.fetch/1) do
     @tag :tmp_dir
diff --git a/test/mix_dependency_submission/fetcher/mix_runtime_test.exs b/test/mix_dependency_submission/fetcher/mix_runtime_test.exs
index 601f900..bcf7ac6 100644
--- a/test/mix_dependency_submission/fetcher/mix_runtime_test.exs
+++ b/test/mix_dependency_submission/fetcher/mix_runtime_test.exs
@@ -4,7 +4,7 @@ defmodule MixDependencySubmission.Fetcher.MixRuntimeTest do
   alias MixDependencySubmission.Fetcher.MixRuntime
   alias MixDependencySubmission.Util
 
-  doctest MixDependencySubmission
+  doctest MixRuntime
 
   describe inspect(&MixRuntime.fetch/1) do
     @tag :tmp_dir
diff --git a/test/mix_dependency_submission/fetcher_test.exs b/test/mix_dependency_submission/fetcher_test.exs
new file mode 100644
index 0000000..1fe4d4e
--- /dev/null
+++ b/test/mix_dependency_submission/fetcher_test.exs
@@ -0,0 +1,7 @@
+defmodule MixDependencySubmission.FetcherTest do
+  use MixDependencySubmission.FixtureCase, async: false
+
+  alias MixDependencySubmission.Fetcher
+
+  doctest Fetcher
+end
diff --git a/test/mix_dependency_submission/scm/hex/scm_test.exs b/test/mix_dependency_submission/scm/hex/scm_test.exs
new file mode 100644
index 0000000..7d977a5
--- /dev/null
+++ b/test/mix_dependency_submission/scm/hex/scm_test.exs
@@ -0,0 +1,7 @@
+defmodule MixDependencySubmission.SCM.Hex.SCMTest do
+  use MixDependencySubmission.FixtureCase, async: false
+
+  alias MixDependencySubmission.SCM.Hex.SCM
+
+  doctest SCM
+end
diff --git a/test/mix_dependency_submission/scm/mix/scm/git_test.exs b/test/mix_dependency_submission/scm/mix/scm/git_test.exs
new file mode 100644
index 0000000..2b076fc
--- /dev/null
+++ b/test/mix_dependency_submission/scm/mix/scm/git_test.exs
@@ -0,0 +1,7 @@
+defmodule MixDependencySubmission.SCM.Mix.SCM.GitTest do
+  use MixDependencySubmission.FixtureCase, async: false
+
+  alias MixDependencySubmission.SCM.Mix.SCM.Git
+
+  doctest Git
+end
diff --git a/test/mix_dependency_submission/scm/mix/scm/path_test.exs b/test/mix_dependency_submission/scm/mix/scm/path_test.exs
new file mode 100644
index 0000000..3feab79
--- /dev/null
+++ b/test/mix_dependency_submission/scm/mix/scm/path_test.exs
@@ -0,0 +1,7 @@
+defmodule MixDependencySubmission.SCM.Mix.SCM.PathTest do
+  use MixDependencySubmission.FixtureCase, async: false
+
+  alias MixDependencySubmission.SCM.Mix.SCM.Path
+
+  doctest Path
+end
diff --git a/test/mix_dependency_submission/scm_test.exs b/test/mix_dependency_submission/scm_test.exs
new file mode 100644
index 0000000..a1f87ef
--- /dev/null
+++ b/test/mix_dependency_submission/scm_test.exs
@@ -0,0 +1,7 @@
+defmodule MixDependencySubmission.SCMTest do
+  use MixDependencySubmission.FixtureCase, async: false
+
+  alias MixDependencySubmission.SCM
+
+  doctest SCM
+end
diff --git a/test/mix_dependency_submission/submission/detector_test.exs b/test/mix_dependency_submission/submission/detector_test.exs
index 16c98b8..3fb7f13 100644
--- a/test/mix_dependency_submission/submission/detector_test.exs
+++ b/test/mix_dependency_submission/submission/detector_test.exs
@@ -3,6 +3,8 @@ defmodule MixDependencySubmission.Submission.DetectorTest do
 
   alias MixDependencySubmission.Submission.Detector
 
+  doctest Detector
+
   describe "Jason.Encoder" do
     test "encodes filled struct" do
       detector = %Detector{
diff --git a/test/mix_dependency_submission/submission/job_test.exs b/test/mix_dependency_submission/submission/job_test.exs
index 4fe1f2e..49df9c7 100644
--- a/test/mix_dependency_submission/submission/job_test.exs
+++ b/test/mix_dependency_submission/submission/job_test.exs
@@ -3,6 +3,8 @@ defmodule MixDependencySubmission.Submission.JobTest do
 
   alias MixDependencySubmission.Submission.Job
 
+  doctest Job
+
   describe "Jason.Encoder" do
     test "encodes filled struct" do
       job = %Job{
diff --git a/test/mix_dependency_submission/submission/manifest/dependency_test.exs b/test/mix_dependency_submission/submission/manifest/dependency_test.exs
index 33f89c6..e834196 100644
--- a/test/mix_dependency_submission/submission/manifest/dependency_test.exs
+++ b/test/mix_dependency_submission/submission/manifest/dependency_test.exs
@@ -3,6 +3,8 @@ defmodule MixDependencySubmission.Submission.Manifest.DependencyTest do
 
   alias MixDependencySubmission.Submission.Manifest.Dependency
 
+  doctest Dependency
+
   describe "Jason.Encoder" do
     test "encodes filled struct" do
       dependency = %Dependency{
diff --git a/test/mix_dependency_submission/submission/manifest/file_test.exs b/test/mix_dependency_submission/submission/manifest/file_test.exs
index e48f161..e65348f 100644
--- a/test/mix_dependency_submission/submission/manifest/file_test.exs
+++ b/test/mix_dependency_submission/submission/manifest/file_test.exs
@@ -3,6 +3,8 @@ defmodule MixDependencySubmission.Submission.Manifest.FileTest do
 
   alias MixDependencySubmission.Submission.Manifest.File
 
+  doctest File
+
   describe "Jason.Encoder" do
     test "encodes filled struct" do
       file = %File{
diff --git a/test/mix_dependency_submission/submission/manifest_test.exs b/test/mix_dependency_submission/submission/manifest_test.exs
index 03837e7..8e091fe 100644
--- a/test/mix_dependency_submission/submission/manifest_test.exs
+++ b/test/mix_dependency_submission/submission/manifest_test.exs
@@ -4,6 +4,8 @@ defmodule MixDependencySubmission.Submission.ManifestTest do
   alias MixDependencySubmission.Submission.Manifest
   alias MixDependencySubmission.Submission.Manifest.File
 
+  doctest Manifest
+
   describe "Jason.Encoder" do
     test "encodes filled struct" do
       manifest = %Manifest{
diff --git a/test/mix_dependency_submission/submission_test.exs b/test/mix_dependency_submission/submission_test.exs
new file mode 100644
index 0000000..fe6ad23
--- /dev/null
+++ b/test/mix_dependency_submission/submission_test.exs
@@ -0,0 +1,46 @@
+defmodule MixDependencySubmission.SubmissionTest do
+  use ExUnit.Case, async: true
+
+  alias MixDependencySubmission.Submission
+
+  doctest Submission
+
+  describe "Jason.Encoder" do
+    test "encodes filled struct" do
+      datetime = DateTime.utc_now()
+
+      submission = %Submission{
+        version: 0,
+        job: %Submission.Job{
+          id: "test",
+          correlator: "test",
+          html_url: URI.parse("http://example.com")
+        },
+        sha: "sha",
+        ref: "ref",
+        detector: %Submission.Detector{
+          name: "test",
+          version: Version.parse!("1.0.0"),
+          url: URI.parse("http://example.com")
+        },
+        metadata: %{"foo" => "bar"},
+        scanned: datetime,
+        manifests: %{}
+      }
+
+      datetime_string = DateTime.to_iso8601(datetime)
+
+      assert %{
+               "detector" => %{"name" => "test", "url" => "http://example.com", "version" => "1.0.0"},
+               "job" => %{"correlator" => "test", "html_url" => "http://example.com", "id" => "test"},
+               "manifests" => %{},
+               "metadata" => %{"foo" => "bar"},
+               "ref" => "ref",
+               "scanned" => ^datetime_string,
+               "sha" => "sha",
+               "version" => 0
+             } =
+               submission |> Jason.encode!() |> Jason.decode!()
+    end
+  end
+end
diff --git a/test/mix_dependency_submission_test.exs b/test/mix_dependency_submission_test.exs
index 71bc284..26e1f8e 100644
--- a/test/mix_dependency_submission_test.exs
+++ b/test/mix_dependency_submission_test.exs
@@ -7,7 +7,7 @@ defmodule MixDependencySubmissionTest do
   alias MixDependencySubmission.Submission.Manifest.Dependency
   alias MixDependencySubmission.Util
 
-  doctest MixDependencySubmission
+  doctest MixDependencySubmission, except: [submission: 1]
 
   describe inspect(&MixDependencySubmission.submission/1) do
     @tag :tmp_dir