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name: anima description: Create crafted, accurate visualizations of anatomy, neurobiology, pharmacology, drugs, cells, and molecular biology. Show real biological structures and make their mechanisms visible, using literal anatomy or a clearly identified mechanical metaphor. Build interactive isometric SVG figures with sourced numbers, accessible motion, optional WebGL, a framed card and live readout. Use for biological explainers, educational illustrations, documentation and interactive figures.

Anima

This skill makes visual explanations of biological structure and function. Show the real structure accurately and make its mechanism visible. Use literal anatomy for structures such as neurons, hearts, cells and organs; use a clearly identified mechanical metaphor for processes when it improves understanding (for example, a receptor and ligand as lock and key, or an ion channel as a gated valve). Never let a metaphor imply that it is the literal biology.

Six biology examples ship with the skill. Open the closest one before you start. Every example is built with node examples/<name>/build.mjs, which writes a standalone HTML page next to the script; add --light for the light theme.

• examples/neuron/ is a neuron with branching dendrites, myelinated axon, animated action-potential readout and hoverable synapse. It is a schematic, and its representative voltage values cite educational sources.
• examples/dopamine-receptors/ is a flat cross-section of a dopamine synapse onto a striatal medium spiny neuron: D1-like receptors couple Gαs/olf and raise cAMP, D2-like receptors couple Gαi/o and lower it, with the full G-protein cycle, a dopamine-level slider and a generic D2-antagonist toggle.
• examples/stimulants-dat/ is a cutaway of a presynaptic dopamine terminal with a NONE, COCAINE or AMPHETAMINE selector: reuptake through the dopamine transporter, blockade, and amphetamine's transport, vesicle leak and reverse efflux. Skeletal formulas come from PubChem records.
• examples/reward-addiction/ is a schematic mid-sagittal brain showing the mesolimbic pathway (VTA to nucleus accumbens, with prefrontal cortex, amygdala and hippocampus), a first-exposure versus repeated-exposure model toggle and a cue sequence. Every claim is framed as one leading model with sources.
• examples/semaglutide-glp1/ is a GLP-1 receptor agonist (semaglutide) acting on a pancreatic beta cell, with glucose-dependent insulin secretion, the molecule's engineered features and the central appetite and reward context.
• examples/estrogen-aggression/ follows testosterone through aromatase to estradiol and estrogen receptor α in an amygdala-type neuron, with an aromatase-block toggle. It states plainly that the human evidence is weak (pooled Fisher z 0.16 across 14 studies).

Each example has a sources block, an educational-not-medical-advice note, a live readout driven by one small model, a pause control, hover or focus explanations and a reduced-motion still frame. Copy the closest one as a template.

The mechanical examples that the craft references cite (a rocket engine, a ripple tank, an arcade cabinet and others) are not shipped here; the references describe them.

The one idea that matters

The real structure is the explanation. Draw the relevant biological structures faithfully, then use motion, cutaways and restrained labels to reveal how they work. A mechanical metaphor is an optional explanatory layer, not a replacement for the biology. Choose the mode that fits the request:

| Mode | Use | |---|---| | Literal anatomy | Neuron, heart, organ, tissue, cell, organelle or molecular structure. Preserve recognizable shape, spatial relationships and relevant scale. | | Mechanical metaphor | A process or interaction that benefits from analogy, such as receptor–ligand binding as a lock and key or an ion channel as a gated valve. Label the analogy and explain where it differs from biology. |

Accuracy takes precedence over decorative detail. Don't invent anatomy, imply a mechanism unsupported by evidence, or make a drawn scale look quantitative unless it is. Every displayed number—including size, concentration, membrane potential, rate and dose—needs a citation in the figure caption or a sources block. Cite primary or authoritative sources, and keep the cited conditions and units visible. Figures are educational, not medical advice; this warning is especially important for drugs and dosing.

Sources first. Collect trusted references before drawing. Reconcile conflicting measurements, identify species/tissue/conditions where relevant, and state uncertainty or omit a number when it cannot be verified. See references/bio.md and the domain guides.

Avoid abstract boxes-and-arrows when a recognizable structure can be shown. Use detailed, purposeful parts, but don't add detail that undermines accuracy or obscures the mechanism.

Every creation is highly detailed. This holds for every figure, however small the idea or request. What scales with the size (workflow step 1) is how far you push it: a Figure gets the 4× sweep over its subject and mechanism, a Hero or an Epic over the whole drawing.

• Read the references. Preserve real structures, spatial relationships and function; detail belongs only where it is supported by evidence.
• Two looks. At 1× the mechanism is clear. At 4×, every detail remains accurate and purposeful.
• Purposeful, never noise. Include only parts that explain biology; do not invent details to fill space.
• Check it last. Zoom to 4× (subject and mechanism for a Figure; the whole drawing for a Hero or Epic) and verify details against sources.

Workflow

Work in this order. Write the concept and the parts list before any geometry. Most of the quality is decided there.

1. Size it before you start. Tell the user which size the request is and roughly how long it will take, before any other work.
   • Figure: one mechanism, 40–80 parts, SVG with at most one WebGL layer. About 30–90 minutes. Build it without asking.
   • Hero: a dense object, several WebGL layers or one 3D subject, 80–150 parts. About 2–4 hours. Say so, then build it unless the user asked for something quick.
   • Epic: a whole organ system, organism, tissue field or multi-scale biological process with many interacting structures. 6 hours or more. Do not start it. Give the estimate, propose a Hero version that keeps the core of the idea, and list what the full version would add. Build the Epic only when the user chooses it.
   • Whatever the size, have a working page that opens in the browser within the first hour, and deepen it from there. Run date at the start and at each step, and when a step runs past twice its share of the estimate, tell the user where it stands and what is left.
2. Sources first. Collect the real structure, behavior and sourced numbers. Record citations alongside the model data. Every number shown in the art or readout must be traceable to a source; don't imply precision beyond the source. If you can, write the model as a small pure module and drive all motion and readouts from it.
3. Choose the representation. State whether this is literal anatomy or a mechanical metaphor. For anatomy, identify structures and relationships that must be visible. For a metaphor, state the mapping and its limits; don't confuse it with the biological object.
4. Parts list. List structures, tissues, molecules, channels, ligands, labels and dynamic elements appropriate to the selected size. Group them by anatomy and function, and make each item purposeful and traceable to references. Consult references/bio.md and the domain guides.
5. Plan the world. Establish a meaningful scale or label the drawing as schematic. Set x, y and z consistently, preserve critical spatial relationships, and make any scale break explicit. Choose the isometric camera and fit the composition to the card.
6. Build geometry once. Precompute every static path in a geometry module with the kit. Use kit/blob.mjs for smooth organic forms, kit/branch.mjs for branches and variable-radius structures, and kit/chem.mjs for molecules, helices and ribbons. Existing kit/lathe.mjs and kit/tube.mjs remain useful for mechanical metaphors. Moving parts are built once at rest and driven by the shared model; rebuild only shapes that change per frame.
7. Paint back to front, bottom to top. Sort repeated parts with depthOf. Split anything that wraps another part into a back half and a front half: the springs around a rod, the bars of a frame around a carriage. A moving part is drawn in the slot where it physically sits. See "Painter's order" in references/craft.md. Once a figure has pipes, cables and round parts, stop tuning keys by eye: record each item's shape as you put it into A.recorder(P, { order, spring }), let A.settle(R, P) measure true depth wherever two items overlap and set the keys, and end the build with A.auditOrExit(R, P). Route pipes before you draw them: real ports at both ends, legs along the structure, crossings on straights, collars gapping the pipe (references/craft.md, section 8). Record the true shape of what you draw: a stand-in shape that silences the audit is a bug, and the audit fails one. A rod that slides out of a gland is one rod from G.rodOut, recorded with A.slide.
8. Frame it. Put the figure in a card: Fig n at top left, a short title at top right, the interaction hint at bottom left and the live readout at bottom right. Add a concise caption and citations for every displayed number under the card or in a sources block. Include the educational-not-medical-advice note, especially for drugs and dosing.
9. Make it live. Use calm time-based motion: exponential follow or real springs. An idle tour loops when nobody touches it. The figure responds to pointer and keyboard, stops when offscreen, and goes still under reduced motion. Write attributes on refs and don't re-render per frame. See references/motion.md.
10. Verify like a critic. The owner finds faults by zooming in, so you zoom in first. Check every label against the parts list and references, verify scale declarations, and run kit/bio-audit.mjs checks for biological figures. Read every PNG you make.

• Capture desktop, phone (390 wide), hover and several moments of motion with scripts/capture.mjs; use scripts/drive.mjs for sequences, the apart pose and the --no-webgl fallback.
• Run the audit to zero. With pipes, cables or round parts, node build.mjs --audit must end audit passed, every failing line at 0: clearance at rest, apart and in mid-flight, terminals, loose ends, folds, self-overlap, crowding (against slender solids too), stand-in shapes, support, wobble, saddles and depth order. Fix an interlock in the geometry, never with a key bias.
• Run the line check to zero. The audit never sees line markup. node scripts/lines.mjs page.html --out shots/lines.png (and on the -light page, and in every resting pose with drive.mjs's ["lines"] action) must print line ends: 0: every seam, rule, rib, tick and pointer ends on a stroke, a dot or an outline. Read the ringed PNG.
• 4× close-ups of every junction in both themes (build --light too), assembled and apart: every flange, tee, elbow, clamp, valve, bellows, band, saddle, ball joint and crossing, every curved body (no tone staircase), every place a texture ends (on an edge or fading), flat box faces with their seams, every textured hose at a chunk joint, every sliding rod at rest and at full stroke, and every window with text or shader content in it.
• Shaders: a contact sheet slowed with ["slow", 0.05] across every transition; nothing pops, no colour switch, edges read 0. In light, also log ink per frame through each transition (it must follow the light monotonically) and crop where the ink meets strokes at 8–16× (references/verify.md,