Bring Anthropic usechat backend to OpenAI-level tool-use parity and stream robustness (#2971)

This updates `pkg/aiusechat/anthropic` from partial implementation to
full backend parity for core tool-use orchestration and stream behavior.
The main gaps were unimplemented tool lifecycle methods, missing
persisted tool-use UI state, and weaker disconnect/error handling versus
the OpenAI backend.

- **Tool-use lifecycle parity (critical path)**
  - Implemented Anthropic backend support for:
    - `UpdateToolUseData`
    - `RemoveToolUseCall`
    - `GetFunctionCallInputByToolCallId`
- Wired `pkg/aiusechat/usechat-backend.go` to call Anthropic
implementations instead of stubs.
- Added Anthropic run-step nil-message guard so `nil` responses are not
wrapped into `[]GenAIMessage{nil}`.

- **Persisted tool-use state in Anthropic native messages**
  - Added internal `ToolUseData` storage on Anthropic `tool_use` blocks.
- Ensured internal-only fields are stripped before API requests via
`Clean()`.

- **UI conversion parity for reloaded history**
- Extended `ConvertToUIMessage()` to emit `data-tooluse` parts when
tool-use metadata exists, in addition to `tool-{name}` parts.

- **Streaming UX parity for tool argument deltas**
  - Added `aiutil.SendToolProgress(...)` calls during:
    - `input_json_delta` (incremental updates)
    - `content_block_stop` for `tool_use` (final update)

- **Disconnect/stream robustness**
  - Added `sse.Err()` checks in event handling and decode-error path.
- Added partial-text extraction on client disconnect and deterministic
ordering of partial blocks.
- Cleans up completed blocks from in-flight state to avoid duplicate
partial extraction.

- **Correctness + hygiene alignment**
- Continuation model checks now use `AreModelsCompatible(...)` (instead
of strict string equality).
- Added hostname sanitization in Anthropic error paths (HTTP error
parsing and `httpClient.Do` failures).
- Replaced unconditional Anthropic debug `log.Printf` calls with
`logutil.DevPrintf`.

- **Targeted coverage additions**
  - Added Anthropic tests for:
    - function-call lookup by tool call id
    - tool-use data update + removal
    - `data-tooluse` UI conversion behavior

```go
// usechat-backend.go
func (b *anthropicBackend) RunChatStep(...) (..., []uctypes.GenAIMessage, ...) {
    stopReason, msg, rateLimitInfo, err := anthropic.RunAnthropicChatStep(ctx, sseHandler, chatOpts, cont)
    if msg == nil {
        return stopReason, nil, rateLimitInfo, err
    }
    return stopReason, []uctypes.GenAIMessage{msg}, rateLimitInfo, err
}
```

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Author: Copilot

frontend/app/aipanel/aipanel.tsx

@@ -306,7 +306,7 @@ const AIPanelComponentInner = memo(() => {
     };
 
     useEffect(() => {
-        globalStore.set(model.isAIStreaming, status == "streaming");
+        globalStore.set(model.isAIStreaming, status === "streaming" || status === "submitted");
     }, [status]);
 
     useEffect(() => {

pkg/aiusechat/anthropic/anthropic-backend.go

@@ -10,8 +10,9 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"log"
 	"net/http"
+	"net/url"
+	"sort"
 	"strings"
 	"time"
 
@@ -20,6 +21,7 @@ import (
 	"github.com/wavetermdev/waveterm/pkg/aiusechat/aiutil"
 	"github.com/wavetermdev/waveterm/pkg/aiusechat/chatstore"
 	"github.com/wavetermdev/waveterm/pkg/aiusechat/uctypes"
+	"github.com/wavetermdev/waveterm/pkg/util/logutil"
 	"github.com/wavetermdev/waveterm/pkg/util/utilfn"
 	"github.com/wavetermdev/waveterm/pkg/web/sse"
 )
@@ -56,10 +58,11 @@ func (m *anthropicChatMessage) GetUsage() *uctypes.AIUsage {
 	}
 
 	return &uctypes.AIUsage{
-		APIType:      uctypes.APIType_AnthropicMessages,
-		Model:        m.Usage.Model,
-		InputTokens:  m.Usage.InputTokens,
-		OutputTokens: m.Usage.OutputTokens,
+		APIType:              uctypes.APIType_AnthropicMessages,
+		Model:                m.Usage.Model,
+		InputTokens:          m.Usage.InputTokens,
+		OutputTokens:         m.Usage.OutputTokens,
+		NativeWebSearchCount: m.Usage.NativeWebSearchCount,
 	}
 }
 
@@ -95,8 +98,9 @@ type anthropicMessageContentBlock struct {
 	Name  string      `json:"name,omitempty"`
 	Input interface{} `json:"input,omitempty"`
 
-	ToolUseDisplayName      string `json:"toolusedisplayname,omitempty"`      // internal field (cannot marshal to API, must be stripped)
-	ToolUseShortDescription string `json:"tooluseshortdescription,omitempty"` // internal field (cannot marshal to API, must be stripped)
+	ToolUseDisplayName      string                        `json:"toolusedisplayname,omitempty"`      // internal field (cannot marshal to API, must be stripped)
+	ToolUseShortDescription string                        `json:"tooluseshortdescription,omitempty"` // internal field (cannot marshal to API, must be stripped)
+	ToolUseData             *uctypes.UIMessageDataToolUse `json:"toolusedata,omitempty"`             // internal field (cannot marshal to API, must be stripped)
 
 	// Tool result content
 	ToolUseID string      `json:"tool_use_id,omitempty"`
@@ -154,6 +158,7 @@ func (b *anthropicMessageContentBlock) Clean() *anthropicMessageContentBlock {
 	rtn.SourcePreviewUrl = ""
 	rtn.ToolUseDisplayName = ""
 	rtn.ToolUseShortDescription = ""
+	rtn.ToolUseData = nil
 	if rtn.Source != nil {
 		rtn.Source = rtn.Source.Clean()
 	}
@@ -177,10 +182,15 @@ type anthropicStreamRequest struct {
 	Stream     bool                           `json:"stream"`
 	System     []anthropicMessageContentBlock `json:"system,omitempty"`
 	ToolChoice any                            `json:"tool_choice,omitempty"`
-	Tools      []uctypes.ToolDefinition       `json:"tools,omitempty"`
+	Tools      []any                          `json:"tools,omitempty"` // *uctypes.ToolDefinition or *anthropicWebSearchTool
 	Thinking   *anthropicThinkingOpts         `json:"thinking,omitempty"`
 }
 
+type anthropicWebSearchTool struct {
+	Type string `json:"type"` // "web_search_20250305"
+	Name string `json:"name"` // "web_search"
+}
+
 type anthropicCacheControl struct {
 	Type string `json:"type"` // "ephemeral"
 	TTL  string `json:"ttl"`  // "5m" or "1h"
@@ -228,8 +238,9 @@ type anthropicUsageType struct {
 	CacheCreationInputTokens int `json:"cache_creation_input_tokens,omitempty"`
 	CacheReadInputTokens     int `json:"cache_read_input_tokens,omitempty"`
 
-	// internal field for Wave use (not sent to API)
-	Model string `json:"model,omitempty"`
+	// internal fields for Wave use (not sent to API)
+	Model                string `json:"model,omitempty"`
+	NativeWebSearchCount int    `json:"nativewebsearchcount,omitempty"`
 
 	// for reference, but we dont keep thsese up to date or track them
 	CacheCreation *anthropicCacheCreationType `json:"cache_creation,omitempty"`  // breakdown of cached tokens by TTL
@@ -290,14 +301,16 @@ type partialJSON struct {
 }
 
 type streamingState struct {
-	blockMap      map[int]*blockState
-	toolCalls     []uctypes.WaveToolCall
-	stopFromDelta string
-	msgID         string
-	model         string
-	stepStarted   bool
-	rtnMessage    *anthropicChatMessage
-	usage         *anthropicUsageType
+	blockMap        map[int]*blockState
+	toolCalls       []uctypes.WaveToolCall
+	stopFromDelta   string
+	msgID           string
+	model           string
+	stepStarted     bool
+	rtnMessage      *anthropicChatMessage
+	usage           *anthropicUsageType
+	chatOpts        uctypes.WaveChatOpts
+	webSearchCount  int
 }
 
 func (p *partialJSON) Write(s string) {
@@ -330,6 +343,20 @@ func (p *partialJSON) FinalObject() (json.RawMessage, error) {
 	}
 }
 
+// sanitizeHostnameInError removes the Wave cloud hostname from error messages
+func sanitizeHostnameInError(err error) error {
+	if err == nil {
+		return nil
+	}
+	errStr := err.Error()
+	parsedURL, parseErr := url.Parse(uctypes.DefaultAIEndpoint)
+	if parseErr == nil && parsedURL.Host != "" && strings.Contains(errStr, parsedURL.Host) {
+		errStr = strings.ReplaceAll(errStr, uctypes.DefaultAIEndpoint, "AI service")
+		errStr = strings.ReplaceAll(errStr, parsedURL.Host, "host")
+	}
+	return fmt.Errorf("%s", errStr)
+}
+
 // makeThinkingOpts creates thinking options based on level and max tokens
 func makeThinkingOpts(thinkingLevel string, maxTokens int) *anthropicThinkingOpts {
 	if thinkingLevel != uctypes.ThinkingLevelMedium && thinkingLevel != uctypes.ThinkingLevelHigh {
@@ -373,21 +400,21 @@ func parseAnthropicHTTPError(resp *http.Response) error {
 	// Try to parse as Anthropic error format first
 	var eresp anthropicHTTPErrorResponse
 	if err := json.Unmarshal(slurp, &eresp); err == nil && eresp.Error.Message != "" {
-		return fmt.Errorf("anthropic %s: %s", resp.Status, eresp.Error.Message)
+		return sanitizeHostnameInError(fmt.Errorf("anthropic %s: %s", resp.Status, eresp.Error.Message))
 	}
 
 	// Try to parse as proxy error format
 	var proxyErr uctypes.ProxyErrorResponse
 	if err := json.Unmarshal(slurp, &proxyErr); err == nil && !proxyErr.Success && proxyErr.Error != "" {
-		return fmt.Errorf("anthropic %s: %s", resp.Status, proxyErr.Error)
+		return sanitizeHostnameInError(fmt.Errorf("anthropic %s: %s", resp.Status, proxyErr.Error))
 	}
 
 	// Fall back to truncated raw response
 	msg := utilfn.TruncateString(strings.TrimSpace(string(slurp)), 120)
 	if msg == "" {
 		msg = "unknown error"
 	}
-	return fmt.Errorf("anthropic %s: %s", resp.Status, msg)
+	return sanitizeHostnameInError(fmt.Errorf("anthropic %s: %s", resp.Status, msg))
 }
 
 func RunAnthropicChatStep(
@@ -426,7 +453,7 @@ func RunAnthropicChatStep(
 
 	// Validate continuation if provided
 	if cont != nil {
-		if chatOpts.Config.Model != cont.Model {
+		if !uctypes.AreModelsCompatible(chat.APIType, chatOpts.Config.Model, cont.Model) {
 			return nil, nil, nil, fmt.Errorf("cannot continue with a different model, model:%q, cont-model:%q", chatOpts.Config.Model, cont.Model)
 		}
 	}
@@ -461,7 +488,7 @@ func RunAnthropicChatStep(
 
 	resp, err := httpClient.Do(req)
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, nil, sanitizeHostnameInError(err)
 	}
 	defer resp.Body.Close()
 
@@ -499,7 +526,7 @@ func RunAnthropicChatStep(
 	// Use eventsource decoder for proper SSE parsing
 	decoder := eventsource.NewDecoder(resp.Body)
 
-	stopReason, rtnMessage := handleAnthropicStreamingResp(ctx, sse, decoder, cont)
+	stopReason, rtnMessage := handleAnthropicStreamingResp(ctx, sse, decoder, cont, chatOpts)
 	return stopReason, rtnMessage, rateLimitInfo, nil
 }
 
@@ -509,6 +536,7 @@ func handleAnthropicStreamingResp(
 	sse *sse.SSEHandlerCh,
 	decoder *eventsource.Decoder,
 	cont *uctypes.WaveContinueResponse,
+	chatOpts uctypes.WaveChatOpts,
 ) (*uctypes.WaveStopReason, *anthropicChatMessage) {
 	// Per-response state
 	state := &streamingState{
@@ -518,6 +546,7 @@ func handleAnthropicStreamingResp(
 			Role:      "assistant",
 			Content:   []anthropicMessageContentBlock{},
 		},
+		chatOpts: chatOpts,
 	}
 
 	var rtnStopReason *uctypes.WaveStopReason
@@ -526,8 +555,10 @@ func handleAnthropicStreamingResp(
 	defer func() {
 		// Set usage in the returned message
 		if state.usage != nil {
-			// Set model in usage for internal use
 			state.usage.Model = state.model
+			if state.webSearchCount > 0 {
+				state.usage.NativeWebSearchCount = state.webSearchCount
+			}
 			state.rtnMessage.Usage = state.usage
 		}
 
@@ -558,6 +589,13 @@ func handleAnthropicStreamingResp(
 				// Normal end of stream
 				break
 			}
+			if sse.Err() != nil {
+				return &uctypes.WaveStopReason{
+					Kind:      uctypes.StopKindCanceled,
+					ErrorType: "client_disconnect",
+					ErrorText: "client disconnected",
+				}, extractPartialTextFromState(state)
+			}
 			// transport error mid-stream
 			_ = sse.AiMsgError(err.Error())
 			return &uctypes.WaveStopReason{
@@ -587,6 +625,37 @@ func handleAnthropicStreamingResp(
 	return rtnStopReason, state.rtnMessage
 }
 
+func extractPartialTextFromState(state *streamingState) *anthropicChatMessage {
+	var content []anthropicMessageContentBlock
+	for _, block := range state.rtnMessage.Content {
+		if block.Type == "text" && block.Text != "" {
+			content = append(content, block)
+		}
+	}
+	var partialIdx []int
+	for idx, st := range state.blockMap {
+		if st.kind == blockText && st.contentBlock != nil && st.contentBlock.Text != "" {
+			partialIdx = append(partialIdx, idx)
+		}
+	}
+	sort.Ints(partialIdx)
+	for _, idx := range partialIdx {
+		st := state.blockMap[idx]
+		if st.kind == blockText && st.contentBlock != nil && st.contentBlock.Text != "" {
+			content = append(content, *st.contentBlock)
+		}
+	}
+	if len(content) == 0 {
+		return nil
+	}
+	return &anthropicChatMessage{
+		MessageId: state.rtnMessage.MessageId,
+		Role:      "assistant",
+		Content:   content,
+		Usage:     state.rtnMessage.Usage,
+	}
+}
+
 // handleAnthropicEvent processes one SSE event block. It may emit SSE parts
 // and/or return a StopReason when the stream is complete.
 //
@@ -601,6 +670,13 @@ func handleAnthropicEvent(
 	state *streamingState,
 	cont *uctypes.WaveContinueResponse,
 ) (stopFromDelta *string, final *uctypes.WaveStopReason) {
+	if err := sse.Err(); err != nil {
+		return nil, &uctypes.WaveStopReason{
+			Kind:      uctypes.StopKindCanceled,
+			ErrorType: "client_disconnect",
+			ErrorText: "client disconnected",
+		}
+	}
 	eventName := event.Event()
 	data := event.Data()
 	switch eventName {
@@ -693,6 +769,10 @@ func handleAnthropicEvent(
 			}
 			state.blockMap[idx] = st
 			_ = sse.AiMsgToolInputStart(tcID, tName)
+		case "server_tool_use":
+			if ev.ContentBlock.Name == "web_search" {
+				state.webSearchCount++
+			}
 		default:
 			// ignore other block types gracefully per Anthropic guidance :contentReference[oaicite:18]{index=18}
 		}
@@ -732,6 +812,7 @@ func handleAnthropicEvent(
 			if st.kind == blockToolUse {
 				st.accumJSON.Write(ev.Delta.PartialJSON)
 				_ = sse.AiMsgToolInputDelta(st.toolCallID, ev.Delta.PartialJSON)
+				aiutil.SendToolProgress(st.toolCallID, st.toolName, st.accumJSON.Bytes(), state.chatOpts, sse, true)
 			}
 		case "signature_delta":
 			// Accumulate signature for thinking blocks
@@ -784,6 +865,7 @@ func handleAnthropicEvent(
 				}
 			}
 			_ = sse.AiMsgToolInputAvailable(st.toolCallID, st.toolName, raw)
+			aiutil.SendToolProgress(st.toolCallID, st.toolName, raw, state.chatOpts, sse, false)
 			state.toolCalls = append(state.toolCalls, uctypes.WaveToolCall{
 				ID:    st.toolCallID,
 				Name:  st.toolName,
@@ -798,6 +880,9 @@ func handleAnthropicEvent(
 			}
 			state.rtnMessage.Content = append(state.rtnMessage.Content, toolUseBlock)
 		}
+		// extractPartialTextFromState reads blockMap for still-in-flight content, so remove completed blocks
+		// once they have been appended to rtnMessage.Content to avoid duplicate text on disconnect.
+		delete(state.blockMap, *ev.Index)
 		return nil, nil
 
 	case "message_delta":
@@ -868,7 +953,7 @@ func handleAnthropicEvent(
 		}
 
 	default:
-		log.Printf("unknown anthropic event type: %s", eventName)
+		logutil.DevPrintf("unknown anthropic event type: %s", eventName)
 		return nil, nil
 	}
 }