diff --git a/doc/output-format.md b/doc/output-format.md
new file mode 100644
index 0000000..64e3e15
--- /dev/null
+++ b/doc/output-format.md
@@ -0,0 +1,19 @@
+# Output Format
+
+`plasp` 3 translates SAS and PDDL files into the same ASP fact format.
+
+## Sections
+
+The `plasp` output contains the following sections:
+
+section | description
+--------|------------
+feature requirements | advanced features (such as conditional effects or axiom rules) required by the input planning problem
+types (PDDL only) | object types used by the planning problem (only if typing is enabled)
+variables | fluents used by the planning problem (variables in SAS and predicates in PDDL) and their possible values
+actions | actions (operators in SAS and actions in PDDL), their preconditions, and effects
+mutex groups (SAS only) | sets of mutually exclusive variable assignments
+axiom rules (SAS only) | special actions that are immediately executed when the preconditions are satisfied
+objects (PDDL only) | constant objects defined by PDDL domains or problems
+initial state | initial variable assignment
+goal | target variable assignment