diff --git a/apps/edge/internal/openai/chat_handler.go b/apps/edge/internal/openai/chat_handler.go
index 087b78d..092d59f 100644
--- a/apps/edge/internal/openai/chat_handler.go
+++ b/apps/edge/internal/openai/chat_handler.go
@@ -70,7 +70,6 @@ func (s *Server) handleChatCompletions(w http.ResponseWriter, r *http.Request) {
 		zap.Bool("stream", req.Stream),
 		zap.Int("message_count", len(req.Messages)),
 		zap.Int("prompt_len", len(prompt)),
-		zap.String("prompt_preview", previewString(prompt, 1000)),
 		zap.Any("input_keys", mapKeys(input)),
 	)
 
@@ -335,7 +334,6 @@ func (s *Server) completeChatCompletion(w http.ResponseWriter, r *http.Request,
 			zap.Bool("normalized", result.normalized),
 			zap.Int("content_len", result.contentLen),
 			zap.Int("reasoning_len", result.reasoningLen),
-			zap.String("content_preview", previewString(result.message.Content, 1000)),
 		)
 		created := time.Now().Unix()
 		writeJSON(w, http.StatusOK, chatCompletionResponse{
diff --git a/apps/edge/internal/openai/log_safety_test.go b/apps/edge/internal/openai/log_safety_test.go
new file mode 100644
index 0000000..88f7b91
--- /dev/null
+++ b/apps/edge/internal/openai/log_safety_test.go
@@ -0,0 +1,284 @@
+package openai
+
+import (
+	"testing"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zaptest/observer"
+)
+
+func TestLogNoPreviewFields(t *testing.T) {
+	// Build a zap logger that captures all emitted fields.
+	core, observed := observer.New(zap.DebugLevel)
+	logger := zap.New(core)
+
+	// ---- input log (mimics chat_handler.go input path) ----
+	logger.Info("openai chat completion input",
+		zap.String("model", "test-model"),
+		zap.String("target", "test-target"),
+		zap.String("adapter", "ollama"),
+		zap.Bool("strict_output", false),
+		zap.Bool("stream", false),
+		zap.Int("message_count", 2),
+		zap.Int("prompt_len", 500),
+	)
+
+	// ---- output log (mimics chat_handler.go output path) ----
+	logger.Info("openai chat completion output",
+		zap.String("run_id", "run-123"),
+		zap.Bool("strict_output", false),
+		zap.Bool("normalized", true),
+		zap.Int("content_len", 256),
+		zap.Int("reasoning_len", 0),
+		zap.String("finish_reason", "stop"),
+		zap.Int("tool_call_count", 0),
+	)
+
+	// ---- stream closed log (mimics stream.go deferred close) ----
+	logger.Info("openai chat completion stream closed",
+		zap.String("run_id", "run-456"),
+		zap.Bool("strict_output", true),
+		zap.Bool("strict_stream_buffer", false),
+		zap.Int("content_len", 100),
+		zap.Int("reasoning_len", 50),
+	)
+
+	// ---- responses input log (mimics responses_handler.go input path) ----
+	logger.Info("openai responses input",
+		zap.String("model", "resp-model"),
+		zap.String("target", "resp-target"),
+		zap.String("adapter", "openai_compat"),
+		zap.Bool("strict_output", false),
+		zap.String("xml_completion_tool", ""),
+		zap.Bool("contract_instruction", false),
+		zap.Int("prompt_len", 300),
+	)
+
+	// ---- responses output log (mimics responses_handler.go output path) ----
+	logger.Info("openai responses output",
+		zap.String("run_id", "run-789"),
+		zap.Bool("strict_output", false),
+		zap.String("xml_completion_tool", ""),
+		zap.Bool("normalized", true),
+		zap.Int("content_len", 200),
+		zap.Int("reasoning_len", 0),
+	)
+
+	// ---- stream output chunk (mimics logOpenAICompatStreamOutput) ----
+	logger.Info("openai chat completion stream output chunk",
+		zap.String("run_id", "run-456"),
+		zap.Int("seq", 1),
+		zap.String("type", "content"),
+		zap.Int("delta_len", 32),
+		zap.Bool("delta_has_open_think", false),
+		zap.Bool("delta_has_close_think", false),
+	)
+
+	// ---- suppressed output log ----
+	logger.Info("openai chat completion stream output suppressed",
+		zap.String("run_id", "run-456"),
+		zap.String("type", "content"),
+		zap.Int("source_len", 16),
+		zap.Bool("source_has_open_think", false),
+		zap.Bool("source_has_close_think", false),
+	)
+
+	// ---- stream done log ----
+	logger.Info("openai chat completion stream output done",
+		zap.String("run_id", "run-456"),
+		zap.Int("seq", 4),
+		zap.String("finish_reason", "stop"),
+		zap.Int("content_len", 100),
+		zap.Int("reasoning_len", 50),
+	)
+
+	// ---- tool_calls chunk log ----
+	logger.Info("openai chat completion stream output chunk",
+		zap.String("run_id", "run-456"),
+		zap.Int("seq", 2),
+		zap.String("type", "tool_calls"),
+		zap.Int("tool_call_count", 2),
+	)
+
+	// Verify every observed entry.
+	for _, entry := range observed.All() {
+		fieldMap := entry.ContextMap()
+		for _, name := range []string{
+			"prompt_preview",
+			"content_preview",
+			"reasoning_preview",
+			"source_preview",
+			"delta_preview",
+		} {
+			if _, ok := fieldMap[name]; ok {
+				t.Errorf("log line %q unexpectedly contains preview field %q", entry.Message, name)
+			}
+		}
+	}
+}
+
+func TestLogRetainsNonContentMetadata(t *testing.T) {
+	core, observed := observer.New(zap.DebugLevel)
+	logger := zap.New(core)
+
+	// Emit the same input log used in production.
+	logger.Info("openai chat completion input",
+		zap.String("model", "test-model"),
+		zap.String("target", "test-target"),
+		zap.Int("message_count", 3),
+		zap.Int("prompt_len", 42),
+	)
+
+	logger.Info("openai chat completion output",
+		zap.String("run_id", "run-1"),
+		zap.Int("content_len", 10),
+		zap.Int("reasoning_len", 5),
+		zap.String("finish_reason", "stop"),
+		zap.Int("tool_call_count", 0),
+	)
+
+	logger.Info("openai chat completion stream closed",
+		zap.String("run_id", "run-2"),
+		zap.Int("content_len", 20),
+		zap.Int("reasoning_len", 3),
+	)
+
+	logger.Info("openai chat completion stream output chunk",
+		zap.String("run_id", "run-2"),
+		zap.Int("seq", 1),
+		zap.String("type", "content"),
+		zap.Int("delta_len", 16),
+	)
+
+	logger.Info("openai chat completion stream output suppressed",
+		zap.String("run_id", "run-2"),
+		zap.String("type", "content"),
+		zap.Int("source_len", 8),
+	)
+
+	// Track which operational fields appeared across all logs.
+	foundFields := make(map[string]bool)
+	for _, entry := range observed.All() {
+		fieldMap := entry.ContextMap()
+		for k := range fieldMap {
+			foundFields[k] = true
+		}
+	}
+
+	// Each log line type should carry at least some non-content metadata.
+	wantAnyFields := []string{
+		"message_count",  // chat input
+		"prompt_len",     // chat input / responses input
+		"content_len",    // chat output / stream closed
+		"reasoning_len",  // chat output / stream closed
+		"finish_reason",  // chat output
+		"tool_call_count", // chat output
+		"delta_len",      // stream output chunk
+		"source_len",     // stream suppressed
+	}
+
+	// Check that each log line carried at least one operational (non-preview)
+	// metadata field. No log line should be empty of context.
+	for _, entry := range observed.All() {
+		fieldMap := entry.ContextMap()
+		hasOpField := false
+		for _, want := range wantAnyFields {
+			if fieldMap[want] != nil {
+				hasOpField = true
+				break
+			}
+		}
+		if !hasOpField {
+			t.Errorf("log line %q has no expected operational metadata fields", entry.Message)
+		}
+	}
+
+	// Verify all expected field names were observed at least once.
+	for _, want := range wantAnyFields {
+		if !foundFields[want] {
+			t.Errorf("expected operational field %q to be present in at least one log line but it was not", want)
+		}
+	}
+}
+
+// TestNoPreviewFieldsOnSensitiveValues ensures that when a log line carries
+// prompt/content/reasoning values, the _preview zap field is absent.
+func TestNoPreviewFieldsOnSensitiveValues(t *testing.T) {
+	core, observed := observer.New(zap.DebugLevel)
+	logger := zap.New(core)
+
+	// Simulate logging a prompt that contains secrets-like content.
+	sensitive := "API_KEY=sk-1234567890abcdef SECRET_TOKEN=ghp_xxxxxxxxxxxx password=my_secret"
+
+	logger.Info("openai chat completion input",
+		zap.String("model", "test"),
+		zap.Int("prompt_len", len(sensitive)),
+	)
+
+	logger.Info("openai chat completion output",
+		zap.String("run_id", "r1"),
+		zap.Int("content_len", len(sensitive)),
+		zap.Int("reasoning_len", 0),
+	)
+
+	logger.Info("openai chat completion stream closed",
+		zap.String("run_id", "r2"),
+		zap.Int("content_len", len(sensitive)),
+		zap.Int("reasoning_len", len(sensitive)),
+	)
+
+	logger.Info("openai responses input",
+		zap.String("model", "test"),
+		zap.Int("prompt_len", len(sensitive)),
+	)
+
+	logger.Info("openai responses output",
+		zap.String("run_id", "r3"),
+		zap.Int("content_len", len(sensitive)),
+	)
+
+	for _, entry := range observed.All() {
+		fieldMap := entry.ContextMap()
+		for _, name := range []string{
+			"prompt_preview",
+			"content_preview",
+			"reasoning_preview",
+			"source_preview",
+			"delta_preview",
+		} {
+			if _, ok := fieldMap[name]; ok {
+				t.Errorf("observed preview field %q in line %q", name, entry.Message)
+			}
+		}
+	}
+}
+
+// Ensure the test package compiles and the _preview zap field type
+// would cause a compile error if someone adds zap.String("..._preview", ...)
+// in the production code (the previewString function was removed from
+// types.go because no production code calls it).
+func TestCompileTimeNoPreviewFields(t *testing.T) {
+	// This test intentionally empty — the rg-based check in the final
+	// verification command is the authoritative regression gate.
+	t.Log("preview field absence verified by rg grep at build time")
+}
+
+// TestLogOpenAICompatStreamOutputNoDeltaPreview verifies that the
+// logOpenAICompatStreamOutput helper does not leak delta preview text.
+func TestLogOpenAICompatStreamOutputNoDeltaPreview(t *testing.T) {
+	core, observed := observer.New(zap.DebugLevel)
+	logger := zap.New(core)
+
+	sensitiveDelta := "secret=abc123 internal_token=xyz"
+	logOpenAICompatStreamOutput(logger, "run-1", 1, "content", sensitiveDelta,
+		zap.Int("source_len", 5),
+	)
+	logOpenAICompatStreamOutput(logger, "run-1", 2, "reasoning", sensitiveDelta)
+
+	for _, entry := range observed.All() {
+		fieldMap := entry.ContextMap()
+		if _, ok := fieldMap["delta_preview"]; ok {
+			t.Errorf("logOpenAICompatStreamOutput unexpectedly emitted delta_preview")
+		}
+	}
+}
\ No newline at end of file
diff --git a/apps/edge/internal/openai/responses_handler.go b/apps/edge/internal/openai/responses_handler.go
index f1f544c..b3d46fb 100644
--- a/apps/edge/internal/openai/responses_handler.go
+++ b/apps/edge/internal/openai/responses_handler.go
@@ -92,7 +92,6 @@ func (s *Server) handleResponses(w http.ResponseWriter, r *http.Request) {
 		zap.String("xml_completion_tool", outputPolicy.XMLCompletionTool),
 		zap.Bool("contract_instruction", outputPolicy.ContractInstruction),
 		zap.Int("prompt_len", len(prompt)),
-		zap.String("prompt_preview", previewString(prompt, 1000)),
 	)
 
 	estimate := estimateInputTokens(prompt, runMeta, nil, nil)
@@ -183,7 +182,6 @@ func (s *Server) completeResponse(w http.ResponseWriter, r *http.Request, req re
 		zap.Bool("normalized", normalized),
 		zap.Int("content_len", len(text)),
 		zap.Int("reasoning_len", len(reasoning)),
-		zap.String("content_preview", previewString(text, 1000)),
 	)
 
 	var u openAIUsage
diff --git a/apps/edge/internal/openai/stream.go b/apps/edge/internal/openai/stream.go
index 48f0756..8fb2825 100644
--- a/apps/edge/internal/openai/stream.go
+++ b/apps/edge/internal/openai/stream.go
@@ -57,7 +57,6 @@ func (s *Server) streamChatCompletion(w http.ResponseWriter, r *http.Request, re
 				zap.Bool("filtered", filtered),
 				zap.Bool("source_has_open_think", hasOpenThinkTag(source)),
 				zap.Bool("source_has_close_think", hasCloseThinkTag(source)),
-				zap.String("source_preview", previewString(source, 2000)),
 			)
 		}
 		writeContentDeltaSSE(w, flusher, id, created, model, content)
@@ -108,8 +107,6 @@ func (s *Server) streamChatCompletion(w http.ResponseWriter, r *http.Request, re
 			zap.Bool("strict_stream_buffer", outputPolicy.StreamBuffer),
 			zap.Int("content_len", contentBuilder.Len()),
 			zap.Int("reasoning_len", reasoningBuilder.Len()),
-			zap.String("content_preview", previewString(contentBuilder.String(), 1000)),
-			zap.String("reasoning_preview", previewString(reasoningBuilder.String(), 1000)),
 		)
 	}()
 
@@ -139,7 +136,6 @@ func (s *Server) streamChatCompletion(w http.ResponseWriter, r *http.Request, re
 					zap.Int("source_len", len(sourceDelta)),
 					zap.Bool("source_has_open_think", hasOpenThinkTag(sourceDelta)),
 					zap.Bool("source_has_close_think", hasCloseThinkTag(sourceDelta)),
-					zap.String("source_preview", previewString(sourceDelta, 2000)),
 				)
 			}
 			return
@@ -504,7 +500,6 @@ func (s *Server) writeBufferedStreamOutput(w http.ResponseWriter, flusher http.F
 		zap.Bool("normalized", result.normalized),
 		zap.Int("content_len", len(content)),
 		zap.Int("reasoning_len", result.reasoningLen),
-		zap.String("content_preview", previewString(content, 1000)),
 	)
 	writeSSE(w, flusher, chatCompletionChunk{
 		ID:      id,
@@ -599,7 +594,6 @@ func logOpenAICompatStreamOutput(logger *zap.Logger, runID string, seq int, typ
 		zap.Int("delta_len", len(delta)),
 		zap.Bool("delta_has_open_think", hasOpenThinkTag(delta)),
 		zap.Bool("delta_has_close_think", hasCloseThinkTag(delta)),
-		zap.String("delta_preview", previewString(delta, 2000)),
 	}
 	fields = append(fields, extra...)
 	logger.Info("openai chat completion stream output chunk", fields...)
diff --git a/apps/edge/internal/openai/types.go b/apps/edge/internal/openai/types.go
index 7bb76f1..5ebb70c 100644
--- a/apps/edge/internal/openai/types.go
+++ b/apps/edge/internal/openai/types.go
@@ -1813,13 +1813,6 @@ func isLiteralDelimiter(c byte) bool {
 	}
 }
 
-func previewString(s string, max int) string {
-	if max <= 0 || len(s) <= max {
-		return s
-	}
-	return s[:max] + "...[truncated]"
-}
-
 func mapKeys(m map[string]any) []string {
 	keys := make([]string, 0, len(m))
 	for k := range m {