chore(release): Update version to v1.4.383

fix: Ollama server now respects the default context window

CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## v1.4.383 (2026-01-18)
+
+### PR [#1943](https://github.com/danielmiessler/Fabric/pull/1943) by [ksylvan](https://github.com/ksylvan): fix: Ollama server now respects the default context window
+
+- Fix: Ollama server now respects the default context window instead of using hardcoded 2048 tokens
+- Add parseOllamaNumCtx() function with type-safe extraction supporting 6 numeric types and platform-aware integer overflow protection
+- Extract num_ctx from client request options and add ModelContextLength field to ChatRequest struct
+- Implement DoS protection via 1,000,000 token maximum limit with sanitized error messages
+- Add comprehensive unit tests for parseOllamaNumCtx function covering edge cases including overflow and invalid types
+
 ## v1.4.382 (2026-01-17)
 
 ### PR [#1941](https://github.com/danielmiessler/Fabric/pull/1941) by [ksylvan](https://github.com/ksylvan): Add `greybeard_secure_prompt_engineer` to metadata, also remove duplicate json data file

cmd/fabric/version.go

@@ -1,3 +1,3 @@
 package main
 
-var version = "v1.4.382"
+var version = "v1.4.383"

internal/server/chat.go

@@ -35,7 +35,8 @@ type PromptRequest struct {
 
 type ChatRequest struct {
 	Prompts            []PromptRequest `json:"prompts"`
-	Language           string          `json:"language"` // Add Language field to bind from request
+	Language           string          `json:"language"`
+	ModelContextLength int             `json:"modelContextLength,omitempty"` // Context window size
 	domain.ChatOptions                 // Embed the ChatOptions from common package
 }
 
@@ -118,7 +119,7 @@ func (h *ChatHandler) HandleChat(c *gin.Context) {
 					}
 				}
 
-				chatter, err := h.registry.GetChatter(p.Model, 2048, p.Vendor, "", true, false)
+				chatter, err := h.registry.GetChatter(p.Model, request.ModelContextLength, p.Vendor, "", true, false)
 				if err != nil {
 					log.Printf("Error creating chatter: %v", err)
 					streamChan <- domain.StreamUpdate{Type: domain.StreamTypeError, Content: fmt.Sprintf("Error: %v", err)}

internal/server/ollama.go

@@ -7,8 +7,10 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"math"
 	"net/http"
 	"net/url"
+	"strconv"
 	"strings"
 	"time"
 
@@ -79,6 +81,111 @@ type FabricResponseFormat struct {
 	Content string `json:"content"`
 }
 
+// parseOllamaNumCtx extracts and validates the num_ctx parameter from Ollama request options.
+// Returns:
+//   - (0, nil) if num_ctx is not present or is null
+//   - (n, nil) if num_ctx is a valid positive integer
+//   - (0, error) if num_ctx is present but invalid
+func parseOllamaNumCtx(options map[string]any) (int, error) {
+	if options == nil {
+		return 0, nil
+	}
+
+	val, exists := options["num_ctx"]
+	if !exists {
+		return 0, nil // Not provided, caller should use default
+	}
+
+	if val == nil {
+		return 0, nil // Explicit null, treat as not provided
+	}
+
+	var contextLength int
+
+	// Platform-specific max int value for overflow checks
+	const maxInt = int64(^uint(0) >> 1)
+
+	switch v := val.(type) {
+	case float64:
+		if math.IsNaN(v) || math.IsInf(v, 0) {
+			return 0, fmt.Errorf("num_ctx must be a finite number")
+		}
+		if math.Trunc(v) != v {
+			return 0, fmt.Errorf("num_ctx must be an integer, got float with fractional part")
+		}
+		// Check for overflow on 32-bit systems (negative values handled by validation at line 166)
+		if v > float64(maxInt) {
+			return 0, fmt.Errorf("num_ctx value out of range")
+		}
+		contextLength = int(v)
+
+	case float32:
+		f64 := float64(v)
+		if math.IsNaN(f64) || math.IsInf(f64, 0) {
+			return 0, fmt.Errorf("num_ctx must be a finite number")
+		}
+		if math.Trunc(f64) != f64 {
+			return 0, fmt.Errorf("num_ctx must be an integer, got float with fractional part")
+		}
+		// Check for overflow on 32-bit systems (negative values handled by validation at line 177)
+		if f64 > float64(maxInt) {
+			return 0, fmt.Errorf("num_ctx value out of range")
+		}
+		contextLength = int(v)
+
+	case int:
+		contextLength = v
+
+	case int64:
+		if v < 0 {
+			return 0, fmt.Errorf("num_ctx must be positive, got: %d", v)
+		}
+		if v > maxInt {
+			return 0, fmt.Errorf("num_ctx value too large: %d", v)
+		}
+		contextLength = int(v)
+
+	case json.Number:
+		i64, err := v.Int64()
+		if err != nil {
+			return 0, fmt.Errorf("num_ctx must be a valid number")
+		}
+		if i64 < 0 {
+			return 0, fmt.Errorf("num_ctx must be positive, got: %d", i64)
+		}
+		if i64 > maxInt {
+			return 0, fmt.Errorf("num_ctx value too large: %d", i64)
+		}
+		contextLength = int(i64)
+
+	case string:
+		parsed, err := strconv.Atoi(v)
+		if err != nil {
+			// Truncate long strings in error messages to avoid logging excessively large input
+			errVal := v
+			if len(v) > 50 {
+				errVal = v[:50] + "..."
+			}
+			return 0, fmt.Errorf("num_ctx must be a valid number, got: %s", errVal)
+		}
+		contextLength = parsed
+
+	default:
+		return 0, fmt.Errorf("num_ctx must be a number, got invalid type")
+	}
+
+	if contextLength <= 0 {
+		return 0, fmt.Errorf("num_ctx must be positive, got: %d", contextLength)
+	}
+
+	const maxContextLength = 1000000
+	if contextLength > maxContextLength {
+		return 0, fmt.Errorf("num_ctx exceeds maximum allowed value of %d", maxContextLength)
+	}
+
+	return contextLength, nil
+}
+
 func ServeOllama(registry *core.PluginRegistry, address string, version string) (err error) {
 	r := gin.New()
 
@@ -161,6 +268,15 @@ func (f APIConvert) ollamaChat(c *gin.Context) {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "testing endpoint"})
 		return
 	}
+
+	// Extract and validate num_ctx from options
+	numCtx, err := parseOllamaNumCtx(prompt.Options)
+	if err != nil {
+		log.Printf("Invalid num_ctx in request: %v", err)
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
 	now := time.Now()
 	var chat ChatRequest
 
@@ -210,6 +326,10 @@ func (f APIConvert) ollamaChat(c *gin.Context) {
 			Variables:   variables,
 		}}
 	}
+
+	// Set context length from parsed num_ctx
+	chat.ModelContextLength = numCtx
+
 	fabricChatReq, err := json.Marshal(chat)
 	if err != nil {
 		log.Printf("Error marshalling body: %v", err)

internal/server/ollama_test.go

@@ -1,6 +1,9 @@
 package restapi
 
 import (
+	"encoding/json"
+	"math"
+	"strings"
 	"testing"
 )
 
@@ -98,3 +101,263 @@ func TestBuildFabricChatURL(t *testing.T) {
 		})
 	}
 }
+
+func TestParseOllamaNumCtx(t *testing.T) {
+	tests := []struct {
+		name    string
+		options map[string]any
+		want    int
+		wantErr bool
+		errMsg  string
+	}{
+		// --- Valid inputs ---
+		{
+			name:    "nil options",
+			options: nil,
+			want:    0,
+			wantErr: false,
+		},
+		{
+			name:    "empty options",
+			options: map[string]any{},
+			want:    0,
+			wantErr: false,
+		},
+		{
+			name:    "num_ctx not present",
+			options: map[string]any{"other_key": 123},
+			want:    0,
+			wantErr: false,
+		},
+		{
+			name:    "num_ctx is null",
+			options: map[string]any{"num_ctx": nil},
+			want:    0,
+			wantErr: false,
+		},
+		{
+			name:    "valid int",
+			options: map[string]any{"num_ctx": 4096},
+			want:    4096,
+			wantErr: false,
+		},
+		{
+			name:    "valid float64 (whole number)",
+			options: map[string]any{"num_ctx": float64(8192)},
+			want:    8192,
+			wantErr: false,
+		},
+		{
+			name:    "valid float32 (whole number)",
+			options: map[string]any{"num_ctx": float32(2048)},
+			want:    2048,
+			wantErr: false,
+		},
+		{
+			name:    "valid json.Number",
+			options: map[string]any{"num_ctx": json.Number("16384")},
+			want:    16384,
+			wantErr: false,
+		},
+		{
+			name:    "valid string",
+			options: map[string]any{"num_ctx": "32768"},
+			want:    32768,
+			wantErr: false,
+		},
+		{
+			name:    "valid int64",
+			options: map[string]any{"num_ctx": int64(65536)},
+			want:    65536,
+			wantErr: false,
+		},
+		// --- Invalid inputs ---
+		{
+			name:    "float64 with fractional part",
+			options: map[string]any{"num_ctx": 4096.5},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be an integer, got float with fractional part",
+		},
+		{
+			name:    "float32 with fractional part",
+			options: map[string]any{"num_ctx": float32(2048.75)},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be an integer, got float with fractional part",
+		},
+		{
+			name:    "negative int",
+			options: map[string]any{"num_ctx": -100},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be positive",
+		},
+		{
+			name:    "zero int",
+			options: map[string]any{"num_ctx": 0},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be positive",
+		},
+		{
+			name:    "negative float64",
+			options: map[string]any{"num_ctx": float64(-500)},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be positive",
+		},
+		{
+			name:    "negative float32",
+			options: map[string]any{"num_ctx": float32(-250)},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be positive",
+		},
+		{
+			name:    "non-numeric string",
+			options: map[string]any{"num_ctx": "not-a-number"},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a valid number",
+		},
+		{
+			name:    "invalid json.Number",
+			options: map[string]any{"num_ctx": json.Number("invalid")},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a valid number",
+		},
+		{
+			name:    "exceeds maximum allowed value",
+			options: map[string]any{"num_ctx": 2000000},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx exceeds maximum allowed value",
+		},
+		{
+			name:    "unsupported type (bool)",
+			options: map[string]any{"num_ctx": true},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a number, got invalid type",
+		},
+		{
+			name:    "unsupported type (slice)",
+			options: map[string]any{"num_ctx": []int{1, 2, 3}},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a number, got invalid type",
+		},
+		// --- Edge cases ---
+		{
+			name:    "minimum valid value",
+			options: map[string]any{"num_ctx": 1},
+			want:    1,
+			wantErr: false,
+		},
+		{
+			name:    "maximum allowed value",
+			options: map[string]any{"num_ctx": 1000000},
+			want:    1000000,
+			wantErr: false,
+		},
+		{
+			name:    "very large float64 (overflow)",
+			options: map[string]any{"num_ctx": float64(math.MaxFloat64)},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx value out of range",
+		},
+		{
+			name:    "large int64 exceeding maxInt on 32-bit",
+			options: map[string]any{"num_ctx": int64(1 << 40)},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx", // either "too large" or "exceeds maximum"
+		},
+		{
+			name:    "long string gets truncated in error",
+			options: map[string]any{"num_ctx": "this-is-a-very-long-string-that-should-be-truncated-in-the-error-message"},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a valid number",
+		},
+		// --- Special float values ---
+		{
+			name:    "float64 NaN",
+			options: map[string]any{"num_ctx": math.NaN()},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a finite number",
+		},
+		{
+			name:    "float64 positive infinity",
+			options: map[string]any{"num_ctx": math.Inf(1)},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a finite number",
+		},
+		{
+			name:    "float64 negative infinity",
+			options: map[string]any{"num_ctx": math.Inf(-1)},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a finite number",
+		},
+		{
+			name:    "float32 NaN",
+			options: map[string]any{"num_ctx": float32(math.NaN())},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a finite number",
+		},
+		{
+			name:    "float32 positive infinity",
+			options: map[string]any{"num_ctx": float32(math.Inf(1))},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a finite number",
+		},
+		{
+			name:    "float32 negative infinity",
+			options: map[string]any{"num_ctx": float32(math.Inf(-1))},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be a finite number",
+		},
+		// --- Negative int64 (32-bit wraparound prevention) ---
+		{
+			name:    "negative int64",
+			options: map[string]any{"num_ctx": int64(-1000)},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be positive",
+		},
+		{
+			name:    "negative json.Number",
+			options: map[string]any{"num_ctx": json.Number("-500")},
+			want:    0,
+			wantErr: true,
+			errMsg:  "num_ctx must be positive",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := parseOllamaNumCtx(tt.options)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("parseOllamaNumCtx() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if err != nil && tt.errMsg != "" {
+				if !strings.Contains(err.Error(), tt.errMsg) {
+					t.Errorf("parseOllamaNumCtx() error message = %q, want to contain %q", err.Error(), tt.errMsg)
+				}
+			}
+			if got != tt.want {
+				t.Errorf("parseOllamaNumCtx() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

nix/pkgs/fabric/version.nix

@@ -1 +1 @@
-"1.4.382"
+"1.4.383"