fix: recover XML tool calls as proper tool execution in agent loop

Move XML tool call extraction from HTTPProvider-only to the central
agent loop so all providers benefit. Plain-text XML tool calls are
now parsed and re-executed as real tool calls, with the XML stripped
from the response content before sending to users.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pkg/agent/loop.go

@@ -1525,6 +1525,14 @@ func (al *AgentLoop) runLLMIteration(
 			)
 		}
 
+		// Recover XML tool calls emitted as plain text by some providers.
+		if len(response.ToolCalls) == 0 {
+			if xmlCalls := providers.ExtractXMLToolCalls(response.Content); len(xmlCalls) > 0 {
+				response.ToolCalls = xmlCalls
+			}
+		}
+		response.Content = providers.StripXMLToolCalls(response.Content)
+
 		// Check if no tool calls - we're done
 		if len(response.ToolCalls) == 0 {
 			// Plan continuation: if unchecked steps remain, nudge the LLM to

pkg/providers/tool_call_extract.go

@@ -171,6 +171,11 @@ func findToolCallBlock(text string) (blockStart, blockEnd int, content string, f
 //	<parameter name="param">value</parameter>
 //	</invoke>
 //	</ns:toolcall>
+// ExtractXMLToolCalls is the exported version for use by the agent loop.
+func ExtractXMLToolCalls(text string) []ToolCall {
+	return extractXMLToolCalls(text)
+}
+
 func extractXMLToolCalls(text string) []ToolCall {
 	var result []ToolCall
 	remaining := text
@@ -260,6 +265,11 @@ func extractXMLToolCalls(text string) []ToolCall {
 	return result
 }
 
+// StripXMLToolCalls is the exported version for use by the agent loop.
+func StripXMLToolCalls(text string) string {
+	return stripXMLToolCalls(text)
+}
+
 // stripXMLToolCalls removes XML tool call blocks from response text.
 // Prevents raw XML tool calls from leaking to users.
 func stripXMLToolCalls(text string) string {