The agent misunderstood me

It happens. You asked for one thing and the ghost preview shows another. The important points are that nothing is committed until you accept, the cost of a miss is small, and almost every misunderstanding has an identifiable cause.

Symptom

• The preview changed the wrong face, edge or piece.
• It changed more than you asked for.
• It ignored a number you gave.
• It made something new when you wanted to edit what exists, or the other way around.
• It used the wrong units or scale.
• An attached image was read as the wrong kind of image.
• It asked a question you thought was obvious.

First, recover calmly

1. Do not accept. Choose Reject (or Tweak if it is nearly right).
2. Open the agent trace. Check the route line: what did it think you wanted, and how confident was it?
3. Look at the change summary. Which parameters changed, how many steps were added?

Everything the agent does is a proposal until you accept, and everything after is undoable.

Likely causes and fixes

The selection was not what you thought

"This" resolves to your current selection. If you selected the whole piece instead of a face, or selected nothing, the agent had to guess.

Fix: click the exact face or edge, check the selection label, and send it again. See Selections and "this".

A key number was missing

If you do not say how much, the agent has to choose. "Make it thicker" could mean 0.5 mm or 5 mm.

Fix: give the value and unit. "Make it 2 mm thicker" or "make the wall 3 mm".

Two requests in one

"Make it smaller and add a hole and round the edges and change the material" is four requests. One may get less care than the others.

Fix: send them separately, or number them. Accept each preview before the next.

The request was ambiguous

"Fix the lid" could mean the fit, the shape, or the hinge.

Fix: describe the problem, not just the object. "The lid is too loose. Add 0.2 mm of interference at the lip."

The agent routed it as something else

The router classifies your message first. A question like "can you make this thicker?" may be treated as a question about feasibility, not an instruction.

Fix: use imperative language. "Make this 3 mm thicker." The trace shows the route.

It edited when you wanted a new thing, or vice versa

Fix: be explicit: "Add a new piece called lid" or "Change the existing lid, do not create a new one".

Units or scale confusion

The model works in millimetres. If you meant inches, say so, and give converted values if it matters.

Fix: "The part is 4 inches (101.6 mm) wide."

An image was misclassified

A photo of a part was treated as a concept image, or a sketch as a drawing.

Fix: say what it is. "This photo shows a broken part, with a coin for scale."

The wrong mode for the job

Complex requests, images, and mechanisms benefit from Smart mode and higher effort.

Fix: switch to Smart, and try again. See Smart vs Fast, and how much effort to ask for.

A rule got in the way

An earlier "always" or "never" may conflict with your request, so the agent held back or flagged a rule.

Fix: check the Design intent chips. Relax the rule, or accept the compromise.

Better prompts, in one table

Make the agent show its reasoning

Before you change anything, tell me what you think I am asking for, which part of the model you will change, and which numbers you will use. Wait for my OK.

List every assumption you made in the last change.

These cost little, and they catch mismatches early.

When it keeps happening

1. Start a clean request with the object, the numbers, and the rules in one message.
2. Break the work down. Shape first, details later.
3. Use Smart mode with Thorough effort for the hard bits.
4. Edit by hand for tiny adjustments. A slider or the Recipe is sometimes quicker than a sentence.
5. Use Tweak to correct a near miss instead of starting again.

How to avoid it

• Select first, then say "this".
• Include units and numbers.
• State what to keep.
• One goal per message.
• Say what success looks like.

Try it

Send this deliberately vague message, then read how the agent responds:

Make it better.

A well-behaved agent will ask what you mean. Now send a precise version, and compare the previews:

Make the base 15 mm wider, keep the height at 40 mm, and round the bottom edges at 2 mm.