gptel-openai: Adapt OpenAI tool-ids for Openrouter+Anthropic

* gptel-openai.el (gptel--openai-format-tool-id,
gptel--openai-unformat-tool-id): It is possible to use the
gptel-openai to access Anthropic backends with Openrouter.  In
this case, the tool call ids are not in the call_* format, and
tool calls fail (#747).  Try to work around this by registering
tool call ids as received when they are not in the call_* format.

This will make the chat log not work when switching backends when
both of these conditions are met: (i) tool results are included in
the buffer and (ii) a non-standard tool call id is in effect.  But
there's not much we can do about it since we no longer tell if the
gptel-openai backend in effect wants call_*, toolu_* or some other
format.

* gptel-anthropic.el (gptel--anthropic-unformat-tool-id): Don't
issue a message if the tool call id is not in the expected form.

Author: karthink

gptel-anthropic.el

@@ -300,9 +300,7 @@ TOOL-USE is a list of plists containing tool names, arguments and call results."
 (defun gptel--anthropic-unformat-tool-id (tool-id)
   (or (and (string-match "toolu_\\(.+\\)" tool-id)
            (match-string 1 tool-id))
-      (progn
-        (message "Unexpected tool_call_id format: %s" tool-id)
-        tool-id)))
+      tool-id))
 
 (cl-defmethod gptel--parse-list ((_backend gptel-anthropic) prompt-list)
   (cl-loop for text in prompt-list

gptel-openai.el

@@ -328,14 +328,18 @@ Mutate state INFO with response metadata."
    tool-use))
 
 (defun gptel--openai-format-tool-id (tool-id)
-  (format "call_%s" tool-id))
+  "Format TOOL-ID for OpenAI.
+
+If the ID has the format used by a different backend, use as-is."
+  (if (or (string-prefix-p "toolu_" tool-id) ;#747
+          (string-prefix-p "call_"  tool-id))
+      tool-id
+    (format "call_%s" tool-id)))
 
 (defun gptel--openai-unformat-tool-id (tool-id)
   (or (and (string-match "call_\\(.+\\)" tool-id)
            (match-string 1 tool-id))
-      (progn
-        (message "Unexpected tool_call_id format: %s" tool-id)
-        tool-id)))
+      tool-id))
 
 ;; NOTE: No `gptel--inject-prompt' method required for gptel-openai, since this
 ;; is handled by its defgeneric implementation