@@ -6,6 +6,25 @@ The format is based on [Keep a
 Changelog](https://keepachangelog.com/en/1.1.0/), and this project adheres to
 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.15.0] - 2026-04-27
+
+### Added
+
+- **`--timeout N` flag**: LLM request timeout in seconds (default: 300). If the
+  LLM API call takes longer than this, the request is aborted and a descriptive
+  error is returned. The timeout is implemented as a `context.WithTimeout`
+  derived from the signal-handling context, so both signal interrupts and
+  timeouts abort the call.
+- **`DefaultLLMTimeout` constant**: Centralises the default timeout value
+  (300 seconds) in `internal/defaults`.
+- **LLM client unit tests**: Three tests for the constructor: timeout default,
+  all-parameter defaults, and API key validation.
+
+### Changed
+
+- **`LLMClient.llmTimeout` field**: Renamed from `timeoutSeconds` for clarity.
+  The field stores the timeout in seconds; 0 means no timeout.
+
 ## [0.14.0] - 2026-04-27
 
 ### Added

@@ -58,6 +58,7 @@
 ### LLM Configuration
 
     --temperature VALUE       Sampling temperature (0.0 to 1.0) (default: 0.7)
+    --timeout N               LLM request timeout in seconds (default: 300)
     --system-prompt TEXT      Custom system prompt for LLM
 
 ### Examples
@@ -188,6 +189,7 @@ | `LLM_AGGREGATOR_BASE_URL` | API base URL (default: "https://api.deepseek.com") |
 | `LLM_AGGREGATOR_MODEL` | Model name (default: "deepseek-chat") |
 | `LLM_AGGREGATOR_MAX_TOKENS` | Maximum tokens in response (default: 4000) |
 | `LLM_AGGREGATOR_TEMPERATURE` | Sampling temperature (default: 0.7) |
+| `LLM_AGGREGATOR_TIMEOUT` | LLM request timeout in seconds (default: 300) |
 | `LLM_AGGREGATOR_SYSTEM_PROMPT` | Custom system prompt |
 | `LLM_AGGREGATOR_MAX_ARTICLES_PER_FEED` | Maximum articles per feed (default: 10) |
 | `LLM_AGGREGATOR_MAX_DAYS_OLD` | Maximum article age in days (default: 7) |

@@ -184,6 +184,7 @@ fmt.Printf("  Include keywords: %s\n", style.Value(fmt.Sprintf("%v", rt.IncludeKeywords)))
 	fmt.Printf("  Exclude keywords: %s\n", style.Value(fmt.Sprintf("%v", rt.ExcludeKeywords)))
 	fmt.Printf("  Output format: %s\n", style.Value(rt.Output))
 	fmt.Printf("  Model: %s\n", style.Value(rt.Model))
+	fmt.Printf("  LLM timeout: %s\n", style.Value(fmt.Sprintf("%d seconds", rt.LLMTimeout)))
 	fmt.Println()
 
 	// Fetch and process feeds (but don't call LLM)

@@ -96,6 +96,21 @@ | `DefaultMaxDaysOld` | `7` | Maximum article age in days |
 | `DefaultMaxTotalArticles` | `20` | Total articles limit |
 | `DefaultOutput` | `text` | Output format |
 | `DefaultIncludeArticles` | `false` | Include articles in output |
+| `DefaultLLMTimeout` | `300` | LLM request timeout (seconds) |
+
+---
+
+### `internal/llm`: LLM client
+
+Tests for the LLM client constructor, defaults, and configuration.
+
+| Test | Description |
+|------|-------------|
+| `TestNewLLMClientTimeout` | Verifies `timeoutSeconds=0` defaults to 300; custom values are stored |
+| `TestNewLLMClientDefaults` | Verifies model, maxTokens, temperature, and llmTimeout all get defaults |
+| `TestNewLLMClientRequiresAPIKey` | Verifies missing API key returns a descriptive error |
+
+**Client field naming:** The `LLMClient` struct uses `llmTimeout int` (seconds; 0 means no timeout) to avoid confusion with `http.Client.Timeout` which operates at the transport layer.
 
 ---
 
@@ -356,7 +371,7 @@ | `output` | 93% | All formatters tested |
 | `processor` | 76% | All filtering/sorting tested |
 | `runtime` | 0% | Integration-only; context propagation not exercised by unit tests |
 | `signals` | 89% | Handler lifecycle and concurrency tested |
-| `llm` | 0% | Requires advanced API mocking |
+| `llm` | 22% | Constructor defaults, API key validation, and timeout field configuration |
 | `tui` | 0% | Requires terminal interaction |
 | `progress` | 0% | Interface only |
 | `tokeniser` | 0% | Depends on library internals |

@@ -1,5 +1,5 @@
 .\" Man page for llm_aggregator
-.TH LLM_AGGREGATOR 1 "27 April 2026" "0.14.0" "User Commands"
+.TH LLM_AGGREGATOR 1 "27 April 2026" "0.15.0" "User Commands"
 .SH NAME
 llm_aggregator \- aggregate RSS feeds and summarise them with LLMs
 .SH SYNOPSIS
@@ -116,12 +116,13 @@ Maximum number of tokens in the LLM response.
 .br
 Default: 4000
 .TP
-.B \-\-temperature \fIVALUE\fR
-Sampling temperature for the LLM (0.0 to 1.0). Higher values produce more
-creative output, lower values produce more deterministic output.
+.B \-\-timeout INR
+LLM request timeout in seconds. If the LLM API call takes longer than
+this, the request is aborted and an error is returned.
 .br
-Default: 0.7
+Default: 300
 .TP
+.B \-\-system\-prompt TEXT
 .B \-\-system\-prompt \fITEXT\fR
 Custom system prompt for the LLM. If not specified, a default prompt is used.
 .SS Output Options

@@ -1,5 +1,5 @@
 .\" Man page for llm_aggregator configuration file
-.TH LLM_AGGREGATOR 5 "27 April 2026" "0.14.0" "File Formats"
+.TH LLM_AGGREGATOR 5 "27 April 2026" "0.15.0" "File Formats"
 .SH NAME
 llm_aggregator.conf \- configuration file for llm_aggregator
 .SH DESCRIPTION
@@ -97,6 +97,12 @@ Lower values produce more deterministic output, higher values produce more
 creative output.
 .br
 Default: 0.7
+.TP
+.B timeout = \fIinteger\fR
+LLM request timeout in seconds. If the LLM API call takes longer than this,
+the request is aborted.
+.br
+Default: 300
 .SH "[system]"
 Options related to the LLM system prompt.
 .TP
@@ -283,6 +289,9 @@ Maximum tokens in response.
 .TP
 .B LLM_AGGREGATOR_TEMPERATURE
 Sampling temperature.
+.TP
+.B LLM_AGGREGATOR_TIMEOUT
+LLM request timeout in seconds.
 .TP
 .B LLM_AGGREGATOR_SYSTEM_PROMPT
 Custom system prompt.

@@ -35,6 +35,7 @@ BaseURL     *string  `arg:"--base-url" help:"API base URL"`
 	Model       *string  `arg:"-m,--model" help:"LLM model to use"`
 	MaxTokens   *int     `arg:"--max-tokens" help:"Maximum tokens in response"`
 	Temperature *float64 `arg:"--temperature" help:"Sampling temperature (0.0 to 1.0)"`
+	Timeout     *int     `arg:"--timeout" help:"LLM request timeout in seconds (default: 300)"`
 
 	// Output options
 	Output          string `arg:"-o,--output" help:"Output format" choice:"text,json,markdown"`
@@ -149,6 +150,9 @@ m["max_tokens"] = *a.MaxTokens
 	}
 	if a.Temperature != nil {
 		m["temperature"] = *a.Temperature
+	}
+	if a.Timeout != nil {
+		m["timeout"] = *a.Timeout
 	}
 	if a.Prompt != "" {
 		m["prompt"] = a.Prompt

@@ -208,6 +208,11 @@ Description: "Sampling temperature (0.0 to 1.0)",
 					Default:     "0.7",
 				},
 				{
+					Name:        "--timeout N",
+					Description: "LLM request timeout in seconds (default: 300)",
+					Default:     "300",
+				},
+				{
 					Name:        "--system-prompt TEXT",
 					Description: "Custom system prompt for LLM",
 				},

@@ -32,6 +32,7 @@ BaseURL     string  `mapstructure:"base_url"`
 	Model       string  `mapstructure:"model"`
 	MaxTokens   int     `mapstructure:"max_tokens"`
 	Temperature float64 `mapstructure:"temperature"`
+	Timeout     int     `mapstructure:"timeout"`
 
 	// System prompt
 	SystemPrompt string `mapstructure:"system_prompt"`
@@ -98,6 +99,7 @@ v.SetDefault("base_url", defaults.DefaultBaseURL)
 	v.SetDefault("model", defaults.DefaultModel)
 	v.SetDefault("max_tokens", defaults.DefaultMaxTokens)
 	v.SetDefault("temperature", defaults.DefaultTemperature)
+	v.SetDefault("timeout", defaults.DefaultLLMTimeout)
 	// System prompt default
 	v.SetDefault("system_prompt", defaults.DefaultSystemPrompt)
 	// Output defaults
@@ -195,6 +197,7 @@ rt.BaseURL = v.GetString("base_url")
 	rt.Model = v.GetString("model")
 	rt.MaxTokens = v.GetInt("max_tokens")
 	rt.Temperature = v.GetFloat64("temperature")
+	rt.LLMTimeout = v.GetInt("timeout")
 	// System prompt
 	rt.SystemPrompt = v.GetString("system_prompt")
 	// Output options
@@ -220,6 +223,7 @@ v.BindEnv("base_url", "LLM_AGGREGATOR_BASE_URL")
 	v.BindEnv("model", "LLM_AGGREGATOR_MODEL")
 	v.BindEnv("max_tokens", "LLM_AGGREGATOR_MAX_TOKENS")
 	v.BindEnv("temperature", "LLM_AGGREGATOR_TEMPERATURE")
+	v.BindEnv("timeout", "LLM_AGGREGATOR_TIMEOUT")
 	// System prompt
 	v.BindEnv("system_prompt", "LLM_AGGREGATOR_SYSTEM_PROMPT")
 	// Output options

@@ -12,6 +12,7 @@ DefaultModel       = "deepseek-chat"
 	DefaultBaseURL     = "https://api.deepseek.com"
 	DefaultMaxTokens   = 4000
 	DefaultTemperature = 0.7
+	DefaultLLMTimeout  = 300 // seconds
 
 	// Feed aggregation defaults
 	DefaultMaxArticlesPerFeed = 10

@@ -16,11 +16,12 @@ )
 
 // LLMClient is a client for interacting with LLM API.
 type LLMClient struct {
-	client      openai.Client
-	model       string
-	maxTokens   int
+	client    openai.Client
+	model     string
+	maxTokens int
 	temperature float64
-	logger      *progress.Context
+	llmTimeout int // seconds; 0 means no timeout
+	logger    *progress.Context
 }
 
 // NewLLMClient creates a new LLM client.
@@ -29,7 +30,8 @@ // baseURL: API base URL (defaults to "https://api.deepseek.com")
 // model: Model to use (defaults to "deepseek-chat")
 // maxTokens: Maximum tokens in response (defaults to 4000)
 // temperature: Sampling temperature (0.0 to 1.0, defaults to 0.7)
-func NewLLMClient(apiKey, baseURL, model string, maxTokens int, temperature float64) (*LLMClient, error) {
+// timeoutSeconds: Request timeout in seconds (defaults to 300)
+func NewLLMClient(apiKey, baseURL, model string, maxTokens int, temperature float64, timeoutSeconds int) (*LLMClient, error) {
 	// Get API key from parameter or environment variable
 	if apiKey == "" {
 		apiKey = os.Getenv("LLM_AGGREGATOR_API_KEY")
@@ -54,6 +56,9 @@ }
 	if temperature == 0 {
 		temperature = defaults.DefaultTemperature
 	}
+	if timeoutSeconds == 0 {
+		timeoutSeconds = defaults.DefaultLLMTimeout
+	}
 
 	// Create OpenAI client configured for LLM
 	clientOpts := []option.RequestOption{
@@ -64,10 +69,11 @@
 	client := openai.NewClient(clientOpts...)
 
 	return &LLMClient{
-		client:      client,
-		model:       model,
-		maxTokens:   maxTokens,
+		client:     client,
+		model:      model,
+		maxTokens:  maxTokens,
 		temperature: temperature,
+		llmTimeout: timeoutSeconds,
 	}, nil
 }
 
@@ -211,6 +217,8 @@ } else if strings.Contains(errStr, "500") {
 			return "", nil, fmt.Errorf("LLM API server error. Please try again later")
 		} else if strings.Contains(errStr, "404") {
 			return "", nil, fmt.Errorf("API endpoint not found. Please check the base URL and endpoint. OpenAI API uses /chat/completions")
+		} else if strings.Contains(errStr, "context deadline exceeded") || strings.Contains(errStr, "context canceled") {
+			return "", nil, fmt.Errorf("LLM request timed out after %d seconds", dc.llmTimeout)
 		}
 		return "", nil, fmt.Errorf("failed to connect to LLM API: %w", err)
 	}

@@ -0,0 +1,81 @@
+package llm
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestNewLLMClientTimeout(t *testing.T) {
+	tests := []struct {
+		name          string
+		timeout       int
+		expectTimeout int
+	}{
+		{
+			name:          "zero timeout uses default 300",
+			timeout:       0,
+			expectTimeout: 300,
+		},
+		{
+			name:          "custom timeout is stored",
+			timeout:       60,
+			expectTimeout: 60,
+		},
+		{
+			name:          "large timeout is stored",
+			timeout:       600,
+			expectTimeout: 600,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// API key is required; use a placeholder
+			client, err := NewLLMClient(
+				"test-api-key",
+				"",
+				"",
+				0,
+				0,
+				tt.timeout,
+			)
+			if err != nil {
+				t.Fatalf("NewLLMClient returned unexpected error: %v", err)
+			}
+			if client.llmTimeout != tt.expectTimeout {
+				t.Errorf("llmTimeout = %d, want %d", client.llmTimeout, tt.expectTimeout)
+			}
+		})
+	}
+}
+
+func TestNewLLMClientDefaults(t *testing.T) {
+	// Verify all defaults are applied when only API key is provided
+	client, err := NewLLMClient("test-api-key", "", "", 0, 0, 0)
+	if err != nil {
+		t.Fatalf("NewLLMClient returned unexpected error: %v", err)
+	}
+
+	if client.model != "deepseek-chat" {
+		t.Errorf("model = %q, want %q", client.model, "deepseek-chat")
+	}
+	if client.maxTokens != 4000 {
+		t.Errorf("maxTokens = %d, want %d", client.maxTokens, 4000)
+	}
+	if client.temperature != 0.7 {
+		t.Errorf("temperature = %f, want %f", client.temperature, 0.7)
+	}
+	if client.llmTimeout != 300 {
+		t.Errorf("llmTimeout = %d, want %d", client.llmTimeout, 300)
+	}
+}
+
+func TestNewLLMClientRequiresAPIKey(t *testing.T) {
+	_, err := NewLLMClient("", "", "", 0, 0, 0)
+	if err == nil {
+		t.Error("NewLLMClient expected error for missing API key, got nil")
+	}
+	if !strings.Contains(err.Error(), "API key is required") {
+		t.Errorf("error message = %q, want to contain %q", err.Error(), "API key is required")
+	}
+}

@@ -30,6 +30,7 @@ BaseURL            string
 	Model              string
 	MaxTokens          int
 	Temperature        float64
+	LLMTimeout         int // seconds; 0 means no timeout
 	Prompt             string
 	SystemPrompt       string
 	Output             string
@@ -139,6 +140,7 @@ r.BaseURL,
 		r.Model,
 		r.MaxTokens,
 		r.Temperature,
+		r.LLMTimeout,
 	)
 	if err != nil {
 		return fmt.Errorf("error initialising LLM client: %w", err)
@@ -150,11 +152,21 @@ r.Progress.SetStage("Getting summary")
 	r.Progress.SetSubStage(fmt.Sprintf("Sending %d articles to LLM", len(processedArticles)))
 	r.Progress.StartWaiting()
 
+	// Derive a timeout context for the LLM call from the parent context.
+	// The parent context carries signal cancellation, so both signal interrupts
+	// and timeouts will abort the call.
+	callCtx := ctx
+	if r.LLMTimeout > 0 {
+		var cancel context.CancelFunc
+		callCtx, cancel = context.WithTimeout(ctx, time.Duration(r.LLMTimeout)*time.Second)
+		defer cancel()
+	}
+
 	summary, usage, err := llm.SummariseArticles(
 		processedArticles,
 		r.Prompt,
 		r.SystemPrompt,
-		ctx,
+		callCtx,
 	)
 	if err != nil {
 		return fmt.Errorf("error getting summary from LLM: %w", err)