diff --git a/ofborg/src/tasks/eval/generic.rs b/ofborg/src/tasks/eval/generic.rs
new file mode 100644
index 0000000..f8462ae
--- /dev/null
+++ b/ofborg/src/tasks/eval/generic.rs
@@ -0,0 +1,45 @@
+use ofborg::checkout::CachedProjectCo;
+use ofborg::commitstatus::CommitStatus;
+use ofborg::evalchecker::EvalChecker;
+use ofborg::message::buildjob::BuildJob;
+use std::path::Path;
+use tasks::eval::{EvaluationStrategy, StepResult};
+
+pub struct GenericStrategy {}
+impl GenericStrategy {
+    pub fn new() -> GenericStrategy {
+        Self {}
+    }
+}
+
+impl EvaluationStrategy for GenericStrategy {
+    fn pre_clone(&mut self) -> StepResult<()> {
+        Ok(())
+    }
+
+    fn on_target_branch(&mut self, _co: &Path, _status: &mut CommitStatus) -> StepResult<()> {
+        Ok(())
+    }
+
+    fn after_fetch(&mut self, _co: &CachedProjectCo) -> StepResult<()> {
+        Ok(())
+    }
+
+    fn merge_conflict(&mut self) {}
+
+    fn after_merge(&mut self, _status: &mut CommitStatus) -> StepResult<()> {
+        Ok(())
+    }
+
+    fn evaluation_checks(&self) -> Vec<EvalChecker> {
+        vec![]
+    }
+
+    fn all_evaluations_passed(
+        &mut self,
+        _co: &Path,
+        _status: &mut CommitStatus,
+    ) -> StepResult<Vec<BuildJob>> {
+        Ok(vec![])
+    }
+}
diff --git a/ofborg/src/tasks/eval/mod.rs b/ofborg/src/tasks/eval/mod.rs
index 35a344b..74b7b2d 100644
--- a/ofborg/src/tasks/eval/mod.rs
+++ b/ofborg/src/tasks/eval/mod.rs
@@ -1,2 +1,33 @@
 pub mod stdenvs;
 pub use self::stdenvs::Stdenvs;
+mod nixpkgs;
+pub use self::nixpkgs::NixpkgsStrategy;
+mod generic;
+pub use self::generic::GenericStrategy;
+use ofborg::checkout::CachedProjectCo;
+use ofborg::commitstatus::CommitStatus;
+use ofborg::evalchecker::EvalChecker;
+use ofborg::message::buildjob::BuildJob;
+use std::path::Path;
+
+pub trait EvaluationStrategy {
+    fn pre_clone(&mut self) -> StepResult<()>;
+    fn on_target_branch(&mut self, co: &Path, status: &mut CommitStatus) -> StepResult<()>;
+    fn after_fetch(&mut self, co: &CachedProjectCo) -> StepResult<()>;
+    fn merge_conflict(&mut self);
+    fn after_merge(&mut self, status: &mut CommitStatus) -> StepResult<()>;
+    fn evaluation_checks(&self) -> Vec<EvalChecker>;
+    fn all_evaluations_passed(
+        &mut self,
+        co: &Path,
+        status: &mut CommitStatus,
+    ) -> StepResult<Vec<BuildJob>>;
+}
+
+type StepResult<T> = Result<T, Error>;
+
+#[derive(Debug)]
+pub enum Error {
+    Fail(String),
+    FailWithGist(String, String, String),
+}
diff --git a/ofborg/src/tasks/eval/nixpkgs.rs b/ofborg/src/tasks/eval/nixpkgs.rs
new file mode 100644
index 0000000..cf30b9d
--- /dev/null
+++ b/ofborg/src/tasks/eval/nixpkgs.rs
@@ -0,0 +1,45 @@
+use ofborg::checkout::CachedProjectCo;
+use ofborg::commitstatus::CommitStatus;
+use ofborg::evalchecker::EvalChecker;
+use ofborg::message::buildjob::BuildJob;
+use std::path::Path;
+use tasks::eval::{EvaluationStrategy, StepResult};
+
+pub struct NixpkgsStrategy {}
+impl NixpkgsStrategy {
+    pub fn new() -> NixpkgsStrategy {
+        Self {}
+    }
+}
+
+impl EvaluationStrategy for NixpkgsStrategy {
+    fn pre_clone(&mut self) -> StepResult<()> {
+        Ok(())
+    }
+
+    fn on_target_branch(&mut self, _co: &Path, _status: &mut CommitStatus) -> StepResult<()> {
+        Ok(())
+    }
+
+    fn after_fetch(&mut self, _co: &CachedProjectCo) -> StepResult<()> {
+        Ok(())
+    }
+
+    fn merge_conflict(&mut self) {}
+
+    fn after_merge(&mut self, _status: &mut CommitStatus) -> StepResult<()> {
+        Ok(())
+    }
+
+    fn evaluation_checks(&self) -> Vec<EvalChecker> {
+        vec![]
+    }
+
+    fn all_evaluations_passed(
+        &mut self,
+        _co: &Path,
+        _status: &mut CommitStatus,
+    ) -> StepResult<Vec<BuildJob>> {
+        Ok(vec![])
+    }
+}