[ManuelStaggl]

A-findings of the full audit (2026-11-12) on the rules for the assistant round the print check, on top of #353, plus the report of 2026-11-12 that the assistant does not optimise print time and material on its own, and the points of the independent review of this PR. origin/main is merged in (undo pattern of #348, block refusals of #355).

R1 – the check reaches the assistant in the turn that changed the design

Before: "Read them after your last change, before you call the part done" was a request. The check reached the model with the next user message; a turn could end on status block it never saw.

After: the work log (workLog.ts) reads SolidCraft's history before and after every changing call. When the design changed, it hands the tool's answer to withCheckOfChange (printCheckNote.ts), which waits until the mirror has delivered that revision and the renderer has reported its check, and puts the note behind the answer. It waits outside the work log's queue.

Why this and not a step at the end of the turn: Claude Code (gate proxy), ChatGPT and local models (loop.ts) all call tools through the one chain track(upstream) in index.ts. One hook there covers all three; a turn-end step would have needed three implementations and a guard against loops. A tool answer cannot loop: no change, no note.

Details, after the review:

• Two stages. With two bodies or a joint the renderer sends the mesh check at once (measuring: true) and the full check when SolidCraft has measured clearance and joints. The answer waits up to 1.5 s for the full check, then takes the mesh check marked as preliminary; after 3 s without any check it says so. Timings at SolidCraft 0.40.1 without a window (median of 5): mirror and mesh check 211 ms for a box with its lid, 141 ms for a hinge; the hinge's two joint sweeps 498 ms; inspect.clearance 1 ms for both; the renderer adds 250 ms of quiet time. Not measured: the renderer's own check time in the app.
• What counts as a change: the undo depth moved, or a change replaced what Redo held (designChanged). The revision alone does not: trials, saves and a block that was taken back move it. Measured: a probe batch that is rolled back leaves revision, undo and redo as they were; body.print_face moves revision and undo depth, so it gets its check.
• Told once. CheckTold gives the full note the first time in a turn and whenever status, findings or the preliminary mark change; else one line plus the measures that changed. A new user message starts over.
• Changing tools now include partbuddy_place_drawing and partbuddy_move_drawing (check, queue, lock while a question is open, a line in the work log). The other PartBuddy tools (view, standard, ask, plan, assembly, design_rules) change no geometry.
• When the history cannot be read, the answer carries no check and the log says so.

Texts to the assistant:

• VIEW_GUIDANCE, replacing the request: PartBuddy checks the part for printing after every change and shows the result to the user as a light; the findings come behind the answer of each tool call that changed the design, and partbuddy_view gives the latest ones.
• Pending behind a tool answer: [PartBuddy: the ready-to-print check of the latest change is still running; call partbuddy_view for it before you call the part done.]
• Pending from partbuddy_view itself: [PartBuddy: the ready-to-print check of the latest change is still running; it will be here in a moment.]
• Preliminary: Preliminary: clearance and joints still being measured (bodies that overlap or come closer than a push fit, joints that stop before a limit); call partbuddy_view for the full check before you call the part done. A clean preliminary check reads nothing found so far (build volume, wall and floor thickness, overhang angle, area on the bed, open bodies, failed features, bodies that touch).
• Unchanged: [PartBuddy: ready-to-print check after this change: unchanged, still not ready to print, the same 1 finding as before.] / … unchanged, nothing found.], followed by Measures that changed: and those lines when there are any.

R3 – a clean check says what it looked at

Before: ready to print, nothing found. / The print check in partbuddy_view still judges what you build.

After (from the finding kinds of printCheck.ts, withClearance, withMotion):

• clean: … nothing found in what it checks (build volume, wall and floor thickness, overhang angle, area on the bed, open bodies, failed features, bodies that touch, bodies that overlap or come closer than a push fit, joints that stop before a limit). and at the end Not checked: strength and layer direction under load, the fits and hole allowances you chose, details and text too fine to print, bed-edge chamfers. Judge those yourself.
• with findings the last line ends with the same Not checked: … sentence.
• standard topics: None of this has been printed by PartBuddy yet, and the print check does not test these rules: measure what you built against them.

R54 – blocks measure the plastic they need

One measure for all four: a probe cylinder is laid in as a body in a batch that is rolled back, and inspect.interference says how much of it lies in the part. The cylinder starts under the face (behind a keyhole's lip, at half the depth of a pocket, seat or countersink), so a curved or sloping face is not read as a gap.

Block	Needs	Measured
keyhole	entry wide, lip + pocket + 1.2 mm deep, behind the entry and behind the screw's rest	before anything is cut
magnet	pocket + 1.2 mm round it + 0.6 mm under it	before anything is cut
insertSeat	the maker's wall round it (at least 2 mm, as a boss) + 0.6 mm under it	after the cut, along the way the hole went in (read from what it took out of the body: solid.hole names no direction); taken back when short
woodScrew	the screw's diameter round the countersink + 0.6 mm of clearance hole under it	the same
any cutting block	the body stays one body	after the cut; taken back

0.6 mm under a seat and under a countersink are our own choice (three layers), marked so in the code.

Refusals, as the engine gave them:

• Not built: at [220, 30, 0] P3 has 3 mm of plastic where 6.7 mm are needed (the mean over a width of 9 mm; the far side, an edge or another cut takes the rest); a keyhole needs the part 6.7 mm thick behind its entry and its slot. Thicken the part there, move the keyhole away from edges and other cuts, or use woodScrew. (an entry over the edge names the entry: at [30, -3, 0] … 2.51 mm)
• magnet: … has 3 mm of plastic where 3.3 mm are needed (the mean over a width of 8.7 mm; …); a pocket needs 1.2 mm of plastic round it and 0.6 mm under it. Thicken the part there, move the pocket away from edges and other cuts, or take a thinner magnet.
• insertSeat: … has 6.54 mm of plastic where 7.3 mm are needed (the mean over a width of 8 mm; …); the seat of an M3 insert needs 2 mm of plastic round it and 0.6 mm under it. Thicken the part there, move the seat away from edges and other cuts, or use a boss. With nothing under the probe's start: has less than 3.35 mm of plastic.
• woodScrew: …; a countersunk hole for a 4 mm wood screw needs 4 mm of plastic round the countersink and a plate at least 2.65 mm thick. Thicken the plate, or move the hole away from edges and other cuts.
• split: Not built: it would leave 2 bodies where Strip was one (Strip (1)): the cut goes right through the part there. Give a point with more plastic round it, or a smaller size

Success answers end with PartBuddy measured that plastic before building: it is there. (keyhole, magnet), PartBuddy measured that plastic: it is there. (insertSeat, woodScrew), or PartBuddy could not measure that plastic this time: check it yourself. insertSeat adds Each seat needs 2 mm of plastic round it and 0.6 mm under it.

At the engine (SolidCraft 0.40.1, audit harness):

• The shared volume is exact, not facetted: seven probe cylinders wholly inside a block, a rod and a ball, along the axes and askew, each gave 1.0000000 of their volume; with 0.02 mm of 2.8 mm outside 0.99286; with 0.01 mm of the width over an edge 0.99993. The threshold stays at 0.999.
• Built, with the measured sentence: keyhole in 8 mm, magnet in 4 mm, insert M3 in 10 mm, wood screw in 8 mm; magnet and two insert seats on a 45° face; magnet and insert seat on a rod of 20 mm radius. On the rod the seat took 0.02 mm more of the stock than on a flat face; 0.3 mm of the seat's depth are allowed for that.
• Refused, nothing left behind (volumes and undo depth unchanged): keyhole in 3 mm and with its entry over the edge; magnet with 0.3 mm under it and 1 mm from a wall; insert seat in 3 mm, in a plate exactly as thick as the seat is deep, 2.5 mm from an edge, and on a 3 mm pilot hole through the part; wood screw 5 in a 3 mm plate and 5 mm from an edge.
• A probe batch leaves revision, undo and redo untouched.
• The harness's bloecke cases (40) pass.

Not measured: the same conditions in mechanismTool.ts (others work there), and whether two pockets of one call leave enough plastic between each other (each is measured against the body before the cuts).

Material and print time (reported 2026-11-12)

Rule group economy (fifth group, on by default; settings switch "Design lean" / "Sparsam konstruieren", partbuddy_design_rules { economy }). Text for a 0.4 mm nozzle and 0.2 mm layers:

• Material and print time, from the first shape on and not as a clean-up: build a shell, not a block. Slicers print 0.9, 1.35, 1.8 mm (two to four lines) as wall and fill anything thicker with sparse infill, so stiffen with ribs as thick as the wall, at least two lines (0.9 mm), instead of thickening the wall. Keep the part low as it prints: every 0.2 mm of height is one more layer, and print time grows with the layers. Shape it so it needs no support, which costs more time and material than any other choice. Leave out whole regions that do nothing (an open frame instead of a plate, a shorter body); small pockets and holes in a filled region add walls and save little or nothing. Split a part only when that saves support or much height and a joint is acceptable. Loaded regions, sizes the user names and what the user wants solid stay as they are. Infill, speed and layer height are set in the slicer: never promise grams or minutes. The print check lists each body's solid volume, height, layers and support area: compare them before and after a change.

The report line becomes After each design step, name what you added on your own, what you did for material and print time and the sizes you snapped in one short line, e.g. "…, shell 1.35 mm with two ribs instead of a solid block".

Measures with every check (tool answers, next message, partbuddy_view), computed in the renderer from the mirrored mesh with meshMetrics and overhangOf:

Per body as it prints. Solid volume overstates what thinning a thick region saves, because the slicer fills it sparsely anyway; the shell estimate (two wall lines on every surface, 15 % infill inside: an assumption, not the slicer's settings) is nearer to the filament. What counts for sure: fewer layers, less area to support, less surface. Promise neither grams nor minutes:
- "Box": 6 cm³ solid, about 2.58 cm³ as a shell, 10 mm high (50 layers), 2200 mm² of surface, 600 mm² on the bed, 0 mm² leaning past the overhang limit.
- "Pin": 90 mm³ solid, about 90 mm³ as a shell, 10 mm high (50 layers), …
- and 3 more bodies.

The shell estimate: surface × two lines, never more than the solid, plus 15 % of the rest. A block 40 × 40 × 20 mm reads 32 cm³ solid and about 9.7 cm³ as a shell; a wall of four lines reads the same in both. Six bodies are listed, the rest counted; volumes under 1 cm³ are given in mm³. No mass: the material profiles carry no density. A body that cannot be measured is left out and named in the log; a report the main process refuses is sent again without measures. packages/geometry is unchanged; laid (print face down) and smallOverhangReach are not exported there, so bodyMeasures.ts repeats the pose and the reach (marked shortcut:).

Yardstick

Topic	Rule with number	Source 1	Source 2	Contradiction
Walls as lines	Whole multiples of the line width; 0.4 nozzle: 0.45/0.9/1.35/1.8 mm for 1–4 perimeters; strength mostly from perimeters; shells typically 0.8 mm	Prusa, https://help.prusa3d.com/en/article/modeling-with-3d-printing-in-mind_164135/ , https://help.prusa3d.com/en/article/layers-and-perimeters_1748	Protolabs Network, https://www.hubs.com/knowledge-base/selecting-optimal-shell-and-infill-parameters-fdm-3d-printing/	Minimum wall differs (Hubs 0.8 mm, UltiMaker 0.5 mm, Stratasys Direct 4 × layer). No source names a thickness above which more wall stops paying off, so the rule names none.
Ribs instead of thick walls	Ribs stiffen thin walls and large flat areas; in FDM a rib needs no thinning. Rule: as thick as the wall, at least two lines	Stratasys Direct FDM guide (p. 4, 7), https://www.stratasys.com/siteassets/sdm/content---website-storage/design-guides/dg_sdm_fdm_0725a.pdf	Protolabs Network, https://www.hubs.com/knowledge-base/dfm-tips-for-3d-printed-parts-with-thin-walls/	Yes: Hubs gives 50–75 % of the wall, the rule of injection moulding against sink marks; on a 0.9 mm wall that is one line, under the thinnest wall that prints. Not taken over. Stratasys Direct also says solid can build faster than hollow with ribs.
Height in Z	Print time follows the layer count: a 10 × 30 mm cylinder is about 100 layers lying, 300 standing (0.1 mm)	Protolabs Network, https://www.hubs.com/knowledge-base/how-does-part-orientation-affect-3d-print/	Xometry, https://www.xometry.com/resources/3d-printing/5-easy-ways-to-reduce-3d-printing-costs/ (wording not verified)	Partly: Markforged names wall length, not height, as the classic driver.
Support	Self-supporting to 45°; bridges 5 mm (Hubs) or 10 mm (UltiMaker); support adds more time than any other factor	Protolabs Network, https://www.hubs.com/knowledge-base/supports-3d-printing-technology-overview/	Markforged, https://www.markforged.com/blog/design-for-3d-printing-part-3-decreasing-print-time ; UltiMaker, https://ultimaker.com/learn/design-for-fff-3d-printing-maximize-your-success/	Bridge 5 vs 10 mm; overhang 45° vs 45–60° (Prusa).
Pockets and holes	Holes may save material but not time: a ring took 10 % longer than the full disc; solid can build faster than hollowed	Markforged, same article	Stratasys Direct, same PDF (p. 7)	Yes, by process: Protolabs gives −36 % volume for hollowing, for SLS/MJF/metal, not FDM.
Bed contact	Largest face on the bed; more contact, less warping	Markforged, https://markforged.com/learn/composites-3d-printing-design-tips	UltiMaker, as above	None; Hubs: strength in XY is 4–5 × that in Z, so load can outrank it.
Splitting	Fewer supports, fits the bed, shorter build; costs a seam, pins and fit allowance	Prusa, as above	Markforged, Stratasys Direct, as above	Clearance figures differ and are printer-specific.
Large flat faces	Prone to warping; break up with ribs, round corners	Protolabs Network, https://www.hubs.com/knowledge-base/key-design-considerations-3d-printing/	Stratasys Direct, same PDF (p. 4)	Severity depends on the machine. Pillowing of large tops: one source only (Polymaker), not in the rule.
The slicer's part	Infill 10–20 % usual, above 40 % rarely sensible; layer height is the main factor of print time (0.1 → 0.2 mm halves it)	Prusa, https://blog.prusa3d.com/everything-you-need-to-know-about-infills_43579/	Protolabs Network (infill article above); Markforged, as above	Hubs contradicts itself on infill vs shells for strength; Prusa sides with shells.

Test expectations changed

• test/printCheckNote.test.ts: ready to print, nothing found → the new clean text and Not checked: ….
• test/standardTool.test.ts: closing sentence of a standard topic.
• test/blockTool.test.ts: the keyhole sends a trial batch (solid.cylinder inspect.interference … sketch.inspect) before its cuts; MAGNET has around and under; the R54 cases run on a plate that answers probes and holes as the engine does.
• test/designRules.test.ts: rule list and defaults carry economy; the report line names material and print time; ribs.
• e2e/app.spec.ts: the list of rule switches carries economy.
• e2e/solidcraft.contract.spec.ts (wall plate): the answers must carry PartBuddy measured that plastic before building: it is there. after the keyholes and the magnets and PartBuddy measured that plastic: it is there. after the wood screws.
• New: test/checkOfChange.test.ts (both routes, no change, bounded wait, two stages, moved revision without change, a failing call that changed the design, undo, two calls at once, unreadable history, drawing tools, told once), test/bodyMeasures.test.ts.

Checked

pnpm run typecheck, eslint . and vitest run in apps/desktop. Audit harness against SolidCraft 0.40.1: bloecke (40 cases), the block cases on flat, sloping and curved faces, the probe shares and the timings above. Not run locally: the app, Playwright E2E and contract tests (CI runs them), a real chat.

🤖 Generated with Claude Code