Request Search Assist explicitly instead of relying on automatic display

docs/plugins.md

@@ -1354,6 +1354,12 @@ waits for answer text with a source link instead of stopping at the empty Search
 Assist heading, and supports expanded answer cards. Browser requests share one
 slot across networks to limit memory use on small hosts.
 
+Both the lightweight and browser lookups explicitly request Search Assist using
+the `assiston=1` web route published in DuckDuckGo's [official bang catalog](https://duckduckgo.com/bang.js)
+for `!assist`. The no-answer search link requests it too. This avoids relying on
+the normal search page's automatic answer-display setting, but is not a public
+Search Assist API, a challenge bypass, or a guarantee of an answer for every query.
+
 The plugin is configured under `plugins.ask`:
 
 ~~~yaml

plugins/ask.go

@@ -780,7 +780,7 @@ func askDuckDuckGoSearchAssist(ctx context.Context, question string) (askSource,
 		if attempt < len(queries) {
 			query = queries[attempt]
 		}
-		if source, ok := askDuckDuckGoSearchAssistOnce(ctx, query, duckDuckGoSearchURL(question)); ok {
+		if source, ok := askDuckDuckGoSearchAssistOnce(ctx, query, duckDuckGoSearchAssistURL(question)); ok {
 			return source, true
 		}
 		if err := ctx.Err(); err != nil {
@@ -830,7 +830,7 @@ func askSearchAssistQueryVariants(question string) []string {
 var askVersusPattern = regexp.MustCompile(`(?i)\bvs\b\.?`)
 
 func askDuckDuckGoSearchAssistOnce(ctx context.Context, question, fallbackURL string) (askSource, bool) {
-	pageURL := duckDuckGoSearchURL(question)
+	pageURL := duckDuckGoSearchAssistURL(question)
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, pageURL, nil)
 	if err != nil {
 		return askSource{}, false
@@ -946,7 +946,7 @@ func askDuckDuckGoRenderedSearchAssist(ctx context.Context, question, browserPat
 		if index < len(queries) {
 			query = queries[index]
 		}
-		if source, ok := askDuckDuckGoRenderedSearchAssistOnce(ctx, query, duckDuckGoSearchURL(question), executable, fetchResults); ok {
+		if source, ok := askDuckDuckGoRenderedSearchAssistOnce(ctx, query, duckDuckGoSearchAssistURL(question), executable, fetchResults); ok {
 			return source, true
 		}
 		if err := ctx.Err(); err != nil {
@@ -986,7 +986,7 @@ func askDuckDuckGoRenderedSearchAssistOnce(ctx context.Context, question, fallba
 	defer browserCancel()
 
 	var result askRenderedSearchAssistData
-	if err := chromedp.Run(browserCtx, chromedp.Navigate(duckDuckGoSearchURL(question))); err != nil {
+	if err := chromedp.Run(browserCtx, chromedp.Navigate(duckDuckGoSearchAssistURL(question))); err != nil {
 		return askSource{}, false
 	}
 	// Navigation and browser startup have already consumed some of the budget.
@@ -1484,6 +1484,14 @@ func duckDuckGoSearchURL(query string) string {
 	return "https://duckduckgo.com/?q=" + url.QueryEscape(strings.TrimSpace(query))
 }
 
+// This is the destination used by DuckDuckGo's official !assist bang
+// (https://duckduckgo.com/bang.js). It requests Search Assist explicitly,
+// rather than relying on the default search setting to display an answer.
+// It is a web route, not an API or a way to bypass provider challenges.
+func duckDuckGoSearchAssistURL(query string) string {
+	return "https://duckduckgo.com/?assiston=1&q=" + url.QueryEscape(strings.TrimSpace(query))
+}
+
 func askHTTPSuccess(status int) bool {
 	return status >= http.StatusOK && status < http.StatusMultipleChoices
 }
@@ -2056,7 +2064,7 @@ func formatAskResponse(nick, answer, sourceURL string, maxLength, maxResponseCha
 
 func formatAskNoAnswer(question string, maxLength int) string {
 	maxLength = clampAskLength(maxLength, 120, 450, 360)
-	return truncateAskBytes("I couldn't find a reliable answer — search: "+duckDuckGoSearchURL(question), maxLength)
+	return truncateAskBytes("I couldn't find a reliable answer — search: "+duckDuckGoSearchAssistURL(question), maxLength)
 }
 
 func clampAskLength(value, min, max, fallback int) int {

plugins/ask_resilience_test.go

@@ -3,6 +3,7 @@ package plugins
 import (
 	"context"
 	"net/http"
+	"net/url"
 	"os"
 	"reflect"
 	"strings"
@@ -72,6 +73,9 @@ func TestAskComparisonRecoversOnNormalizedRetry(t *testing.T) {
 		if r.URL.Path == "/assist.js" {
 			return newPluginResponse(200, `DDG.deep.deepPayload={"instantAnswers":[{"data":{"answer":"Compare equivalent dirt bikes and go-karts, including maintenance costs.","sources":[{"article":{"link":"https://example.org/comparison"}}]}}]};callback();`), nil
 		}
+		if r.URL.Query().Get("assiston") != "1" {
+			t.Fatal("Search Assist was not explicitly requested")
+		}
 		queries = append(queries, r.URL.Query().Get("q"))
 		if len(queries) == 1 {
 			return newPluginResponse(200, `<html><body>No answer yet</body></html>`), nil
@@ -87,6 +91,18 @@ func TestAskComparisonRecoversOnNormalizedRetry(t *testing.T) {
 	}
 }
 
+func TestAskExplicitAssistURL(t *testing.T) {
+	for _, question := range []string{"how much do dirt bikes cost vs GoKarts?", "R&D vs C++? &assiston=0", "日本語の質問"} {
+		u, err := url.Parse(duckDuckGoSearchAssistURL(question))
+		if err != nil || u.Host != "duckduckgo.com" || u.Scheme != "https" || u.Query().Get("q") != question || !reflect.DeepEqual(u.Query()["assiston"], []string{"1"}) {
+			t.Fatalf("invalid explicit route: %v %v", u, err)
+		}
+	}
+	if !strings.Contains(formatAskNoAnswer("a question", 360), "?assiston=1&q=a+question") {
+		t.Fatal("fallback link does not request Search Assist")
+	}
+}
+
 func TestAskComparisonDoesNotReturnEntityDescription(t *testing.T) {
 	old := askHTTPClient
 	t.Cleanup(func() { askHTTPClient = old })

plugins/ask_test.go

@@ -484,7 +484,7 @@ func TestAskResponseDropsInvalidSourceURL(t *testing.T) {
 
 func TestAskNoAnswerProvidesSearchFallback(t *testing.T) {
 	got := formatAskNoAnswer("Is the Earth flat?", 180)
-	if !strings.Contains(got, "I couldn't find a reliable answer") || !strings.Contains(got, "https://duckduckgo.com/?q=Is+the+Earth+flat%3F") {
+	if !strings.Contains(got, "I couldn't find a reliable answer") || !strings.Contains(got, "https://duckduckgo.com/?assiston=1&q=Is+the+Earth+flat%3F") {
 		t.Fatalf("formatAskNoAnswer() = %q, want bounded search fallback", got)
 	}
 	if strings.ContainsAny(got, "\r\n") || len([]byte(got)) > 180 {