Flow inputs carry an origin hint, run or panel

The Inputs editor and the canvas label show it, and the run forms leave
panel inputs out.

frontend/src/components/Flow/FlowBoundary.tsx

@@ -6,6 +6,7 @@ import { MessagesService } from "@/client"
 import { Button } from "@/components/ui/button"
 import { Checkbox } from "@/components/ui/checkbox"
 import { Input } from "@/components/ui/input"
+import { Segmented } from "@/components/ui/segmented"
 import {
   Select,
   SelectContent,
@@ -160,6 +161,12 @@ function usePublishInput() {
   })
 }
 
+/** What writes an input: a run passing it in, or a control on a panel. */
+const ORIGINS = [
+  ["run", "run"],
+  ["panel", "panel"],
+] as const
+
 function InputRow({
   flow,
   declared,
@@ -231,34 +238,44 @@ function InputRow({
         </Button>
       </div>
 
-      {live && name ? (
-        <div className="flex items-center gap-2 pl-1 text-xs text-muted-foreground">
-          <span className="shrink-0">now</span>
-          {current === undefined ? (
-            <span className="flex-1">—</span>
-          ) : (
-            <span className="min-w-0 flex-1">
-              <ValuePreview value={current.value} dtype={spec.dtype} />
-            </span>
-          )}
-          <Tooltip>
-            <TooltipTrigger asChild>
-              <Button
-                variant="ghost"
-                size="icon-sm"
-                aria-label="Publish this value now"
-                disabled={publish.isPending || declared.initial === null}
-                onClick={() =>
-                  publish.mutate({ message, value: declared.initial })
-                }
-              >
-                <ArrowUpFromLine />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>Put this value into the flow now</TooltipContent>
-          </Tooltip>
-        </div>
-      ) : null}
+      <div className="flex items-center gap-2 pl-1 text-xs text-muted-foreground">
+        <Segmented
+          label="Written by"
+          value={declared.origin ?? "run"}
+          options={ORIGINS}
+          onChange={(origin) =>
+            onChange({ ...declared, origin: origin as typeof declared.origin })
+          }
+        />
+        {live && name ? (
+          <>
+            <span className="shrink-0">now</span>
+            {current === undefined ? (
+              <span className="flex-1">—</span>
+            ) : (
+              <span className="min-w-0 flex-1">
+                <ValuePreview value={current.value} dtype={spec.dtype} />
+              </span>
+            )}
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <Button
+                  variant="ghost"
+                  size="icon-sm"
+                  aria-label="Publish this value now"
+                  disabled={publish.isPending || declared.initial === null}
+                  onClick={() =>
+                    publish.mutate({ message, value: declared.initial })
+                  }
+                >
+                  <ArrowUpFromLine />
+                </Button>
+              </TooltipTrigger>
+              <TooltipContent>Put this value into the flow now</TooltipContent>
+            </Tooltip>
+          </>
+        ) : null}
+      </div>
     </div>
   )
 }
@@ -338,8 +355,9 @@ export function BoundarySections({
         <div className="flex items-center justify-between">
           <span className={PANEL_SECTION}>Inputs</span>
           <InfoTip label="Inputs">
-            Messages that arrive from outside, such as a dashboard control, a
-            run or the API, and the value the flow starts from.
+            Messages that arrive from outside, and the value the flow starts
+            from. A run passes a run input in, a dashboard or panel control
+            writes a panel input.
           </InfoTip>
           <Button
             variant="ghost"

frontend/src/components/Flow/RunDialog.tsx

@@ -94,9 +94,16 @@ export function initialText(inputs: FlowInput_Input[]): Record<string, string> {
   )
 }
 
-/** The declared inputs worth drawing a field for. */
+/**
+ * The declared inputs worth drawing a field for.
+ *
+ * A panel input is a control's to write, so a run keeps its starting value
+ * and the form does not offer it as a parameter.
+ */
 export function declaredInputs(definition: FlowDef_Input): FlowInput_Input[] {
-  return (definition.inputs ?? []).filter((one) => one.spec?.name)
+  return (definition.inputs ?? []).filter(
+    (one) => one.spec?.name && one.origin !== "panel",
+  )
 }
 
 /**

frontend/src/components/Flow/deriveEdges.ts

@@ -91,11 +91,14 @@ export function deriveEdges(nodes: NodeDef_Input[], flow: string): Edge[] {
  */
 export function boundaryKey(doc: {
   mode?: string | null
-  inputs?: { spec?: MessageSpec | null }[] | null
+  inputs?: { spec?: MessageSpec | null; origin?: string }[] | null
   outputs?: string[] | null
 }): string {
   const inputs = (doc.inputs ?? [])
-    .map((one) => `${one.spec?.name ?? ""}:${one.spec?.dtype ?? ""}`)
+    .map(
+      (one) =>
+        `${one.spec?.name ?? ""}:${one.spec?.dtype ?? ""}:${one.origin ?? ""}`,
+    )
     .join(",")
   return `${doc.mode ?? "live"}|${inputs}|${(doc.outputs ?? []).join(",")}`
 }

frontend/src/components/Flow/endpoints.ts

@@ -62,7 +62,8 @@ function boundaryOf(
       kind: "input",
       id: `input:${message}`,
       label: displayName(flow, message),
-      detail: declared.spec?.dtype ?? "float",
+      // What writes it, so a control's input does not read as a run's.
+      detail: `${declared.origin ?? "run"} · ${declared.spec?.dtype ?? "float"}`,
       provides: [message],
       requires: [],
     })