revert: replace fullwidth pipe ｜ with halfwidth | in DSML tool markup

PR #460 introduced fullwidth pipe characters (｜) in DSML tool call formatting
to improve parsing robustness, but models exposed to these fullwidth pipes in
system prompts exhibit significantly higher rates of tool output hallucinations.
Reverting to halfwidth pipes (|) drastically reduces tokenizer/perplexity-driven
hallucinations while retaining the existing confusable-hardening in the parser.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/httpapi/claude/current_input_file_test.go

@@ -93,7 +93,11 @@ func (d *claudeCurrentInputDS) GetPow(context.Context, *auth.RequestAuth, int) (
 
 func (d *claudeCurrentInputDS) UploadFile(_ context.Context, _ *auth.RequestAuth, req dsclient.UploadFileRequest, _ int) (*dsclient.UploadFileResult, error) {
 	d.uploads = append(d.uploads, req)
-	return &dsclient.UploadFileResult{ID: "file-claude-history"}, nil
+	id := "file-claude-history"
+	if len(d.uploads) > 1 {
+		id = "file-claude-tools"
+	}
+	return &dsclient.UploadFileResult{ID: id}, nil
 }
 
 func (d *claudeCurrentInputDS) CallCompletion(_ context.Context, _ *auth.RequestAuth, payload map[string]any, _ string, _ int) (*http.Response, error) {
@@ -156,3 +160,47 @@ func TestClaudeDirectAppliesCurrentInputFile(t *testing.T) {
 		t.Fatalf("expected persisted message to match upstream continuation prompt, got %#v", full.Messages)
 	}
 }
+
+func TestClaudeCurrentInputFileUploadsToolsSeparately(t *testing.T) {
+	ds := &claudeCurrentInputDS{}
+	h := &Handler{
+		Store: mockClaudeConfig{aliases: map[string]string{"claude-sonnet-4-6": "deepseek-v4-flash"}},
+		Auth:  claudeCurrentInputAuth{},
+		DS:    ds,
+	}
+	reqBody := `{"model":"claude-sonnet-4-6","messages":[{"role":"user","content":"hello from claude"}],"tools":[{"name":"search","description":"Search docs","input_schema":{"type":"object"}}],"max_tokens":1024}`
+	req := httptest.NewRequest(http.MethodPost, "/v1/messages", strings.NewReader(reqBody))
+	req.Header.Set("Content-Type", "application/json")
+	rec := httptest.NewRecorder()
+
+	h.Messages(rec, req)
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d body=%s", rec.Code, rec.Body.String())
+	}
+	if len(ds.uploads) != 2 {
+		t.Fatalf("expected history and tools uploads, got %d", len(ds.uploads))
+	}
+	if ds.uploads[0].Filename != "DS2API_HISTORY.txt" || ds.uploads[1].Filename != "DS2API_TOOLS.txt" {
+		t.Fatalf("unexpected upload filenames: %#v", ds.uploads)
+	}
+	historyText := string(ds.uploads[0].Data)
+	if strings.Contains(historyText, "You have access to these tools") || strings.Contains(historyText, "Description: Search docs") {
+		t.Fatalf("history transcript should not embed tool descriptions, got %q", historyText)
+	}
+	toolsText := string(ds.uploads[1].Data)
+	if !strings.Contains(toolsText, "# DS2API_TOOLS.txt") || !strings.Contains(toolsText, "Tool: search") || !strings.Contains(toolsText, "Description: Search docs") {
+		t.Fatalf("expected tools transcript to include tool schema, got %q", toolsText)
+	}
+	refIDs, _ := ds.payload["ref_file_ids"].([]any)
+	if len(refIDs) < 2 || refIDs[0] != "file-claude-history" || refIDs[1] != "file-claude-tools" {
+		t.Fatalf("expected history and tools ref ids first, got %#v", ds.payload["ref_file_ids"])
+	}
+	prompt, _ := ds.payload["prompt"].(string)
+	if !strings.Contains(prompt, "DS2API_TOOLS.txt") || !strings.Contains(prompt, "TOOL CALL FORMAT") {
+		t.Fatalf("expected live prompt to reference tools file and retain format instructions, got %q", prompt)
+	}
+	if strings.Contains(prompt, "Description: Search docs") {
+		t.Fatalf("live prompt should not inline tool descriptions, got %q", prompt)
+	}
+}

internal/httpapi/claude/handler_util_test.go

@@ -93,10 +93,10 @@ func TestNormalizeClaudeMessagesToolUseToAssistantToolCalls(t *testing.T) {
 		t.Fatalf("expected call id preserved, got %#v", call)
 	}
 	content, _ := m["content"].(string)
-	if !containsStr(content, "<｜DSML｜tool_calls>") || !containsStr(content, `<｜DSML｜invoke name="search_web">`) {
+	if !containsStr(content, "<|DSML|tool_calls>") || !containsStr(content, `<|DSML|invoke name="search_web">`) {
 		t.Fatalf("expected assistant content to include DSML tool call history, got %q", content)
 	}
-	if !containsStr(content, `<｜DSML｜parameter name="query"><![CDATA[latest]]></｜DSML｜parameter>`) {
+	if !containsStr(content, `<|DSML|parameter name="query"><![CDATA[latest]]></|DSML|parameter>`) {
 		t.Fatalf("expected assistant content to include serialized parameters, got %q", content)
 	}
 }
@@ -133,7 +133,7 @@ func TestNormalizeClaudeMessagesPreservesThinkingOnToolUseHistory(t *testing.T)
 	if !containsStr(prompt, "[reasoning_content]\nneed live search before answering\n[/reasoning_content]") {
 		t.Fatalf("expected thinking in prompt history, got %q", prompt)
 	}
-	if !containsStr(prompt, `<｜DSML｜invoke name="search_web">`) {
+	if !containsStr(prompt, `<|DSML|invoke name="search_web">`) {
 		t.Fatalf("expected tool call in prompt history, got %q", prompt)
 	}
 }
@@ -329,7 +329,7 @@ func TestBuildClaudeToolPromptSingleTool(t *testing.T) {
 	if !containsStr(prompt, "Search the web") {
 		t.Fatalf("expected description in prompt")
 	}
-	if !containsStr(prompt, "<｜DSML｜tool_calls>") {
+	if !containsStr(prompt, "<|DSML|tool_calls>") {
 		t.Fatalf("expected DSML tool_calls format in prompt")
 	}
 	if !containsStr(prompt, "TOOL CALL FORMAT") {

internal/httpapi/claude/standard_request.go

@@ -52,7 +52,7 @@ func normalizeClaudeRequest(store ConfigReader, req map[string]any) (claudeNorma
 			RequestedModel:  strings.TrimSpace(model),
 			ResolvedModel:   dsModel,
 			ResponseModel:   strings.TrimSpace(model),
-			Messages:        payload["messages"].([]any),
+			Messages:        normalizedMessages,
 			PromptTokenText: finalPrompt,
 			ToolsRaw:        toolsRequested,
 			FinalPrompt:     finalPrompt,