Distinguish connection tools with semantic palette icons

crates/oa-desktop/src/app/architecture_authoring/palette.rs

@@ -1,5 +1,6 @@
 //! Compact neutral tool palette. Tool state never changes its allocated width.
 use super::*;
+use crate::connection_tool::Tool;
 use iced::{
     Point, Rectangle, Size, Theme, mouse,
     widget::{
@@ -11,7 +12,7 @@ use iced::{
 #[derive(Clone, Copy)]
 enum Icon {
     Element(Kind),
-    Arrow,
+    Connection(Tool),
     Existing,
     Select,
     Collapse(bool),
@@ -76,10 +77,63 @@ impl canvas::Program<Message> for Icon {
                     );
                 }
             }
-            Self::Arrow => {
-                f.stroke(&line(&[(1., 8.), (14., 8.), (10., 4.)]), stroke);
-                f.stroke(&line(&[(14., 8.), (10., 12.)]), stroke);
+            Self::Connection(connection) => match connection {
+                // The OA and SA work-flow tools share a visual family; they
+                // never coexist in a palette. Keep their small glyph legible.
+                Tool::Interaction | Tool::FunctionalExchange => {
+                    for x in [1., 11.] {
+                        f.stroke(
+                            &Path::rounded_rectangle(
+                                Point::new(x, 5.),
+                                Size::new(4., 6.),
+                                1.5.into(),
+                            ),
+                            stroke,
+                        );
                     }
+                    f.stroke(&line(&[(5., 8.), (10., 8.)]), stroke);
+                    f.stroke(&line(&[(7.5, 5.5), (10., 8.), (7.5, 10.5)]), stroke);
+                }
+                Tool::CommunicationMean => {
+                    // Participant endpoints, without implying a fixed direction.
+                    for x in [1., 11.] {
+                        f.stroke(
+                            &Path::rectangle(Point::new(x, 4.), Size::new(4., 8.)),
+                            stroke,
+                        );
+                    }
+                    f.stroke(&line(&[(5., 8.), (11., 8.)]), stroke);
+                }
+                Tool::BoundaryExchange => {
+                    // Ports on facing participant boundaries. Standard exchanges
+                    // are unoriented, so the generic tool has no arrowhead.
+                    for x in [2., 14.] {
+                        f.stroke(&line(&[(x, 2.), (x, 14.)]), stroke);
+                    }
+                    for x in [1., 12.] {
+                        f.stroke(
+                            &Path::rectangle(Point::new(x, 6.), Size::new(3., 4.)),
+                            stroke,
+                        );
+                    }
+                    f.stroke(&line(&[(4., 8.), (12., 8.)]), stroke);
+                }
+                Tool::Allocation => {
+                    // Work enters a performer: allocation can appear as nesting
+                    // rather than a relationship line in allocated-work views.
+                    f.stroke(&line(&[(1., 2.), (1., 14.), (15., 14.), (15., 2.)]), stroke);
+                    f.stroke(
+                        &Path::rounded_rectangle(
+                            Point::new(5., 9.),
+                            Size::new(6., 3.),
+                            1.into(),
+                        ),
+                        stroke,
+                    );
+                    f.stroke(&line(&[(8., 1.), (8., 7.)]), stroke);
+                    f.stroke(&line(&[(5., 4.), (8., 7.), (11., 4.)]), stroke);
+                }
+            },
             Self::Existing => {
                 f.stroke(
                     &Path::rectangle(Point::new(1., 1.), Size::new(10., 10.)),
@@ -234,7 +288,7 @@ pub fn view(app: &App) -> Element<'_, Message> {
         }
         content = content.push(tool(
             app,
-            Icon::Arrow,
+            Icon::Connection(*connection),
             connection.label(),
             Message::Connection(crate::connection_edit::Event::Choose(Some(*connection))),
             app.connection

harness/connection-icons-20260925.md

@@ -0,0 +1,11 @@
+# Connection tool icons
+
+Branch candidate for [#41](http://217.177.34.108:3000/sorokin.oleg.edu/ARCADIA-Studio/issues/41), based on published Windows preview source `715036e132677dd2bc2fb37ed316d93dc9987aec`. This is not integrated or native acceptance.
+
+The reported collapsed palette repeats one arrow for three different tools. Extend the existing Rust/Iced canvas glyphs at their actual 16×16 size: work endpoints plus an arrow for Interaction/Functional exchange, neutral participant endpoints for Communication means, facing component ports for Boundary exchange, and work entering a performer for Allocation. The first pair never coexist in one perspective. Unoriented generic tools must not imply a fixed direction.
+
+Letter badges were rejected as language-dependent and cramped. Different arrow/dash styles risk confusing tool identity with relation direction. Native endpoint/container shapes fit the existing icon system without font or asset dependencies. Preserve button dimensions, explicit labels/tooltips, ordering, messages, availability and selection rules.
+
+Independent source critique found no blocker and confirmed the tool semantics and Iced API use. Actual-size legibility remains unverified, particularly the exchange arrow, port details and possible download/import interpretation of Allocation. Verify enabled, disabled, hovered and selected palettes in both perspectives, expansion/collapse, tool activation, representative relation creation and cancellation. Existing keyboard/accessibility behavior must be checked, not inferred from hover labels. Reuse semantic connection tests; geometry hashes alone are not an identification or usability evaluator.
+
+Linux remains excluded by the existing user pause. Live ownership and integration status belong to the linked issue.