feat: update the web_search_coyote tool to attempt to use the current model first then fallback to the configured model for web searches

assets/functions/tools/web_search_coyote.sh

@@ -8,10 +8,17 @@ set -e
 
 # @meta require-tools coyote
 
-# @env WEB_SEARCH_MODEL=gemini:gemini-2.5-flash The model for web-searching.
+# @env WEB_SEARCH_MODEL=gemini:gemini-2.5-flash The fallback model for web-searching.
 #
-# supported coyote models:
-#   - gemini:gemini-2.0-*
+# Model selection: when WEB_SEARCH_USE_CURRENT_MODEL is true (the default) and
+# the running session's model (COYOTE_CURRENT_MODEL, injected by coyote for
+# every tool call) natively supports web search, the search runs on the current
+# model first. If the current model is unsupported, or if the search fails at
+# runtime, the tool falls back to WEB_SEARCH_MODEL. If that also fails, the
+# tool fails.
+#
+# supported coyote models (native web search):
+#   - gemini:*
 #   - vertexai:gemini-*
 #   - perplexity:*
 #   - ernie:*
@@ -20,29 +27,74 @@ set -e
 #                                     client — the codex OAuth path uses the
 #                                     Responses API where this parameter
 #                                     does not exist)
+# @env WEB_SEARCH_USE_CURRENT_MODEL=true Prefer the running session's model when it natively supports web search.
 # @env LLM_OUTPUT=/dev/stdout The output path
 
-# shellcheck disable=SC2154
-main() {
-    client="${WEB_SEARCH_MODEL%%:*}"
+# Returns 0 when the model natively supports web search via a known mechanism.
+supports_native_search() {
+    case "$1" in
+    gemini:* | vertexai:gemini-* | perplexity:* | ernie:* | claude:*) return 0 ;;
+    openai:gpt-4o*search-preview*) return 0 ;;
+    *) return 1 ;;
+    esac
+}
 
-    if [[ "$client" == "gemini" ]]; then
+# Exports the request-body patch that enables native web search for the
+# given model's client (clearing any patch left over from a prior attempt).
+export_search_patch() {
+    unset COYOTE_PATCH_GEMINI_CHAT_COMPLETIONS \
+        COYOTE_PATCH_VERTEXAI_CHAT_COMPLETIONS \
+        COYOTE_PATCH_ERNIE_CHAT_COMPLETIONS \
+        COYOTE_PATCH_CLAUDE_CHAT_COMPLETIONS \
+        COYOTE_PATCH_OPENAI_CHAT_COMPLETIONS
+
+    case "${1%%:*}" in
+    gemini)
         export COYOTE_PATCH_GEMINI_CHAT_COMPLETIONS='{".*":{"body":{"tools":[{"google_search":{}}]}}}'
-    elif [[ "$client" == "vertexai" ]]; then
+        ;;
+    vertexai)
         export COYOTE_PATCH_VERTEXAI_CHAT_COMPLETIONS='{
     "gemini-1.5-.*":{"body":{"tools":[{"googleSearchRetrieval":{}}]}},
     "gemini-2.0-.*":{"body":{"tools":[{"google_search":{}}]}}
 }'
-    elif [[ "$client" == "ernie" ]]; then
+        ;;
+    ernie)
         export COYOTE_PATCH_ERNIE_CHAT_COMPLETIONS='{".*":{"body":{"web_search":{"enable":true}}}}'
-    elif [[ "$client" == "claude" ]]; then
+        ;;
+    claude)
         export COYOTE_PATCH_CLAUDE_CHAT_COMPLETIONS='{".*":{"body":{"tools":[{"type":"web_search_20250305","name":"web_search","max_uses":5}]}}}'
-    elif [[ "$client" == "openai" ]]; then
+        ;;
+    openai)
         # Chat Completions native search exists only on the search-preview
         # models; the regex scopes the patch so other OpenAI models run
         # unpatched instead of erroring on an unsupported parameter.
         export COYOTE_PATCH_OPENAI_CHAT_COMPLETIONS='{"gpt-4o.*search-preview.*":{"body":{"web_search_options":{}}}}'
+        ;;
+    esac
+}
+
+# shellcheck disable=SC2154
+run_search() {
+    export_search_patch "$1"
+    coyote -m "$1" "$argc_query" >>"$LLM_OUTPUT"
+}
+
+main() {
+    local fallback="${WEB_SEARCH_MODEL:-gemini:gemini-2.5-flash}"
+    local current="${COYOTE_CURRENT_MODEL:-}"
+    local primary=""
+
+    if [[ "${WEB_SEARCH_USE_CURRENT_MODEL:-true}" == "true" && -n "$current" && "$current" != "$fallback" ]] &&
+        supports_native_search "$current"; then
+        primary="$current"
     fi
 
-    coyote -m "$WEB_SEARCH_MODEL" "$argc_query" >> "$LLM_OUTPUT"
+    if [[ -n "$primary" ]]; then
+        if run_search "$primary"; then
+            return 0
+        fi
+        echo "web_search: search with current model '$primary' failed; falling back to '$fallback'" >&2
+    fi
+
+    run_search "$fallback"
 }