Writing action lines in a screenplay
Between one line of dialogue and the next, in a screenplay, are the action lines: the description of what happens on screen. It's the part where writers coming from fiction bring the most habits that don't work here, because a screenplay isn't a text read for the pleasure of the prose: it's a working document that has to communicate quickly what the viewer will see.
Only what the camera shoots
The fundamental rule of action lines is that they describe only what's seen and heard: gestures, movements, visible expressions, sounds, objects, environments. They don't describe what a character feels inside, their past, their thoughts, their unexpressed intentions.
"Marco is destroyed by guilt over what happened ten years earlier" isn't action: there's no way to shoot it. "Marco stares at the photograph. He turns it face down" is action: it shows the same inner state through what's seen. The screenwriter's job is to find the visible gesture that communicates the invisible.
Present tense, short blocks
Action lines are written in the present indicative: "enters," "turns," "takes the glass." And they're broken into short blocks, often one or two lines, separated by spaces. A long paragraph of action slows the reading and hides the important moments inside a wall of text.
Breaking action into blocks also has an implicit directing function: each block tends to correspond to a shot or a movement, and the length of the blocks communicates the pace. Short, clipped blocks read fast; the eye skims, and that speed is the information that tells the reader "this scene is frantic."
Concrete verbs, few adjectives
Strong action rests on verbs: "grabs," "hurls," "whispers" say more than "takes violently," "throws forcefully," "says in a low voice." A precise verb removes the need for the adverb.
Adjectives should be used sparingly, and only when they add visible information that matters: "a bare room" says something; "a melancholy room full of memories" describes an atmosphere the set design will render its own way and that doesn't help the reader see the scene.
Reading speed is part of the text
In screenwriting, how fast a page reads is deliberate information. An action scene written in very short blocks, with sentences of a few words, reads in seconds, and that sense of speed is what communicates the scene's pace to whoever reads it — a producer, a director, an actor. A slow, dense dialogue scene reads more slowly, and that's fine.
Writing action without thinking about reading speed is like writing music without thinking about tempo: the text works on the page but doesn't convey the rhythm it will have on screen.
What not to put in action lines
Off the action lines: characters' thoughts, their past, their non-visible motivations, overly detailed directing notes ("tight close-up on..."), extended atmosphere description. Also the names of objects that never appear on screen and worldbuilding information the audience won't see. Every action line that describes something the viewer won't perceive is a line written for the wrong reader.
Working on action lines in revision
Action lines almost always get trimmed in revision: in the first draft they tend to be too dense, with novel-like descriptions that slow the page. Rereading a scene while timing how long it takes to read, and comparing it with the pace it should have, helps you see where to cut. In NovLore, the text's scene structure and version history live in the same place, so you can trim a scene's action and recover the earlier version if you cut something that was needed.
Frequently asked questions
Can I write what a character is thinking in the action lines?
No, not in the sense of describing an inner thought directly. You can, however, show the thought through a visible gesture: a hesitation, a look, an object picked up and set back down. The work is translating the inner into the visible.
How long can action lines be?
As short as possible while staying clear. Blocks of one or two lines are the norm; a block of five or six lines in a row is almost always a sign the action needs breaking up or trimming. The length of the blocks communicates the pace, so it should be controlled the way you control pace.
Should I indicate shots in the action lines?
Generally no, unless the shot is structurally necessary to the scene. Development screenplays tend to leave shooting choices to the director: breaking action into blocks already suggests an edit without having to state it.