Phrases the agent understands
A short vocabulary of words and phrases that map directly to something the agent does: keep, always, this, symmetric, fits an M3, centered, no supports and more.
You can talk to the agent in any natural wording. But a small set of words does particularly useful work, because each one reliably signals something concrete: a lasting rule, a selection, a hole type, a print constraint. Learn these and your prompts get shorter and more dependable.
Rules that last
| Say | What happens | Example |
|---|---|---|
| keep | Protects something from change in this edit and in later ones | "Keep the mounting holes where they are." |
| always | Creates a lasting design intent rule | "Always keep the lid the same width as the box." |
| never | A rule with a limit | "Never let the wall go below 1.6 mm." |
| no matter | A rule that survives other changes | "Keep these holes centered no matter the width." |
| at least / no thinner than | A minimum, checked after every rebuild | "Walls at least 2 mm." |
| at most / under | A maximum | "Overall height under 120 mm." |
These become chips in the Design intent section, green while they hold and red if something breaks them. See Design intent.
Pointing
| Say | What happens |
|---|---|
| this, here, that | Resolves to your current selection |
| these | Applies to all selected items |
| all of these, all the holes like this | Selects similar items |
| the top face, the front edge | Describes a target without selecting. Top means up (the +Z direction) |
Shape relationships
| Say | What happens |
|---|---|
| centered | Position defined as the middle, so it stays centered when sizes change |
| symmetric | Mirrored across a plane or axis |
| equal, the same size | Linked values |
| flush with | Aligned face to face |
| evenly spaced | Positions defined by a spacing formula |
| linked to, follows | A parameter formula ("lid width follows box width") |
| a pattern of N | Linear, circular or along-a-path repeats |
Holes and fasteners
| Say | What happens |
|---|---|
| fits an M3, for an M3 screw | A clearance hole sized for the screw |
| tapped M4 | A threaded hole |
| heat-set M3, for an insert | A hole sized for a heat-set insert |
| counterbored, countersunk | The screw head sits below or flush with the surface |
| through, blind 8 mm deep | The depth |
| fasten these | The agent chooses fitting screws, nuts and inserts |
Supported thread sizes include M2, M2.5, M3, M4, M5, M6, M8, M10, M12, plus a few imperial ones (1/4-20, #4-40, #6-32).
Making and printing
| Say | What happens |
|---|---|
| no supports | Overhangs are redesigned (chamfers, teardrops) rather than supported |
| prints flat, print it on its side | Sets an orientation for the check |
| for FDM / PETG / on a Prusa MK4 | Applies that process, material and bed |
| 0.25 mm clearance or slip fit | A specific fit, ideally stored in a parameter |
| printable in two pieces | A split with joints |
| for the CNC shop | Machining-friendly design and shop-oriented drawings |
History and safety
| Say | What happens |
|---|---|
| branch or try this on a branch | Creates a branch so main is untouched |
| compare with main | Shows a diff |
| undo, go back to before the lid | Rewinds, using history |
| tag this as v1.0 | Adds a release tag |
| don't change anything else | Strengthens the "keep" for the rest of the model |
Questions
You can ask without changing anything:
| Say | What you get |
|---|---|
| What's the clearance between these? | A measurement on the model |
| How much does it weigh in PETG? | Volume and weight |
| Why did you do that? | An explanation (teaching mode) |
| List your assumptions | The values it chose where you did not specify |
| Can I print this? | A manufacturability check |
Parameters
| Say | What happens |
|---|---|
| make that a parameter | A named, adjustable value |
| set wall_thickness to 2.4 | A direct parameter change |
| group these under Fit | Organizes the Parameters panel |
| slider from 1 to 4 mm | Sets min and max |
Words that cause trouble
| Avoid | Because | Try instead |
|---|---|---|
| "bigger", "smaller" with no number | The agent has to guess how much | "20 mm wider" or "scale by 120 percent" |
| "nice", "clean", "good" | Not measurable | "radius 3 mm on all outer edges" |
| "like before" | May refer to an unknown state | Name the commit or describe it |
| "fix it" | Which problem? | Say what is wrong |
| Two instructions that conflict | Forces a choice | Resolve them yourself |
Putting it together
Add four clearance holes for M3 screws, 6 mm in from the corners of this face, countersunk. Always keep them symmetric about the center. Never let the plate go thinner than 3 mm. Don't change anything else.
That one sentence group uses a selection ("this face"), a hole type, a position, a lasting rule, a minimum, and a protection.
Try it
Choose any model, select a face, and send:
Keep this face where it is, always. Make the rest of the part 20 percent thinner.
Watch how "keep" and "always" show up as a rule chip, and how the ghost preview leaves the selected face alone.
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