diff --git a/cmd/gateway_providers.go b/cmd/gateway_providers.go
index 80702bfb..c4e365a9 100644
--- a/cmd/gateway_providers.go
+++ b/cmd/gateway_providers.go
@@ -41,7 +41,9 @@ func registerProviders(registry *providers.Registry, cfg *config.Config) {
 	}
 
 	if cfg.Providers.OpenRouter.APIKey != "" {
-		registry.Register(providers.NewOpenAIProvider("openrouter", cfg.Providers.OpenRouter.APIKey, "https://openrouter.ai/api/v1", "anthropic/claude-sonnet-4-5-20250929"))
+		orProv := providers.NewOpenAIProvider("openrouter", cfg.Providers.OpenRouter.APIKey, "https://openrouter.ai/api/v1", "anthropic/claude-sonnet-4-5-20250929")
+		orProv.WithSiteInfo("https://goclaw.sh", "GoClaw")
+		registry.Register(orProv)
 		slog.Info("registered provider", "name", "openrouter")
 	}
 
@@ -404,6 +406,9 @@ func registerProvidersFromDB(registry *providers.Registry, provStore store.Provi
 			if p.ProviderType == store.ProviderMiniMax {
 				prov.WithChatPath("/text/chatcompletion_v2")
 			}
+			if p.ProviderType == store.ProviderOpenRouter {
+				prov.WithSiteInfo("https://goclaw.sh", "GoClaw")
+			}
 			registry.RegisterForTenant(p.TenantID, prov)
 		}
 		slog.Info("registered provider from DB", "name", p.Name)
diff --git a/internal/agent/systemprompt_sections.go b/internal/agent/systemprompt_sections.go
index 42ae9d8b..d59e881e 100644
--- a/internal/agent/systemprompt_sections.go
+++ b/internal/agent/systemprompt_sections.go
@@ -55,7 +55,14 @@ func buildMCPToolsInlineSection(descs map[string]string) []string {
 		mcpOptionalParamInstruction,
 		"",
 	}
-	for name, desc := range descs {
+	// Sort MCP tool names for deterministic ordering — critical for prompt caching.
+	sortedNames := make([]string, 0, len(descs))
+	for name := range descs {
+		sortedNames = append(sortedNames, name)
+	}
+	slices.Sort(sortedNames)
+	for _, name := range sortedNames {
+		desc := descs[name]
 		if len(desc) > mcpToolDescMaxLen {
 			desc = desc[:mcpToolDescMaxLen] + "…"
 		}
diff --git a/internal/providers/openai.go b/internal/providers/openai.go
index fcd057f4..8f4f4a56 100644
--- a/internal/providers/openai.go
+++ b/internal/providers/openai.go
@@ -27,6 +27,8 @@ type OpenAIProvider struct {
 	authPrefix   string // auth header prefix, defaults to "Bearer " if empty
 	defaultModel string
 	providerType string // DB provider_type (e.g. "gemini_native", "openai", "minimax_native")
+	siteURL      string // optional site URL for provider identification (e.g. OpenRouter HTTP-Referer)
+	siteTitle    string // optional site title for provider identification (e.g. OpenRouter X-Title)
 	client       *http.Client
 	retryConfig  RetryConfig
 }
@@ -114,6 +116,14 @@ func (p *OpenAIProvider) WithAuthPrefix(prefix string) *OpenAIProvider {
 	return p
 }
 
+// WithSiteInfo sets site identification headers sent with API requests.
+// Used by OpenRouter for rankings (HTTP-Referer, X-Title).
+func (p *OpenAIProvider) WithSiteInfo(url, title string) *OpenAIProvider {
+	p.siteURL = url
+	p.siteTitle = title
+	return p
+}
+
 func (p *OpenAIProvider) Name() string           { return p.name }
 func (p *OpenAIProvider) DefaultModel() string   { return p.defaultModel }
 func (p *OpenAIProvider) SupportsThinking() bool { return true }
@@ -576,6 +586,13 @@ func (p *OpenAIProvider) doRequest(ctx context.Context, body any) (io.ReadCloser
 		}
 		httpReq.Header.Set("Authorization", prefix+p.apiKey)
 	}
+	// OpenRouter identification headers for rankings/analytics
+	if p.siteURL != "" {
+		httpReq.Header.Set("HTTP-Referer", p.siteURL)
+	}
+	if p.siteTitle != "" {
+		httpReq.Header.Set("X-Title", p.siteTitle)
+	}
 
 	resp, err := p.client.Do(httpReq)
 	if err != nil {
diff --git a/internal/store/pg/agents_context.go b/internal/store/pg/agents_context.go
index b1763fc7..7684d3bd 100644
--- a/internal/store/pg/agents_context.go
+++ b/internal/store/pg/agents_context.go
@@ -25,7 +25,7 @@ func (s *PGAgentStore) GetAgentContextFiles(ctx context.Context, agentID uuid.UU
 		return nil, err
 	}
 	rows, err := s.db.QueryContext(ctx,
-		"SELECT agent_id, file_name, content FROM agent_context_files WHERE agent_id = $1"+tClause,
+		"SELECT agent_id, file_name, content FROM agent_context_files WHERE agent_id = $1"+tClause+" ORDER BY file_name",
 		append([]any{agentID}, tArgs...)...)
 	if err != nil {
 		return nil, err
@@ -87,7 +87,7 @@ func (s *PGAgentStore) GetUserContextFiles(ctx context.Context, agentID uuid.UUI
 		return nil, err
 	}
 	rows, err := s.db.QueryContext(ctx,
-		"SELECT agent_id, user_id, file_name, content FROM user_context_files WHERE agent_id = $1 AND user_id = $2"+tClause,
+		"SELECT agent_id, user_id, file_name, content FROM user_context_files WHERE agent_id = $1 AND user_id = $2"+tClause+" ORDER BY file_name",
 		append([]any{agentID, userID}, tArgs...)...)
 	if err != nil {
 		return nil, err
diff --git a/internal/store/sqlitestore/agents_context.go b/internal/store/sqlitestore/agents_context.go
index a3dc2418..cded9c0c 100644
--- a/internal/store/sqlitestore/agents_context.go
+++ b/internal/store/sqlitestore/agents_context.go
@@ -27,7 +27,7 @@ func (s *SQLiteAgentStore) GetAgentContextFiles(ctx context.Context, agentID uui
 		return nil, err
 	}
 	rows, err := s.db.QueryContext(ctx,
-		"SELECT agent_id, file_name, content FROM agent_context_files WHERE agent_id = ?"+tClause,
+		"SELECT agent_id, file_name, content FROM agent_context_files WHERE agent_id = ?"+tClause+" ORDER BY file_name",
 		append([]any{agentID}, tArgs...)...)
 	if err != nil {
 		return nil, err
@@ -97,7 +97,7 @@ func (s *SQLiteAgentStore) GetUserContextFiles(ctx context.Context, agentID uuid
 		return nil, err
 	}
 	rows, err := s.db.QueryContext(ctx,
-		"SELECT agent_id, user_id, file_name, content FROM user_context_files WHERE agent_id = ? AND user_id = ?"+tClause,
+		"SELECT agent_id, user_id, file_name, content FROM user_context_files WHERE agent_id = ? AND user_id = ?"+tClause+" ORDER BY file_name",
 		append([]any{agentID, userID}, tArgs...)...)
 	if err != nil {
 		return nil, err
diff --git a/internal/tools/policy.go b/internal/tools/policy.go
index e7f70a0e..57df0a84 100644
--- a/internal/tools/policy.go
+++ b/internal/tools/policy.go
@@ -130,8 +130,16 @@ func (pe *PolicyEngine) FilterTools(
 		}
 	}
 
-	// Add registry aliases for allowed canonical tools
-	for alias, canonical := range registry.Aliases() {
+	// Add registry aliases for allowed canonical tools.
+	// Sort alias names for deterministic ordering (prompt caching).
+	aliasMap := registry.Aliases()
+	aliasList := make([]string, 0, len(aliasMap))
+	for alias := range aliasMap {
+		aliasList = append(aliasList, alias)
+	}
+	slices.Sort(aliasList)
+	for _, alias := range aliasList {
+		canonical := aliasMap[alias]
 		if !allowedSet[canonical] {
 			continue
 		}
diff --git a/internal/tools/registry.go b/internal/tools/registry.go
index 0325a464..490841f8 100644
--- a/internal/tools/registry.go
+++ b/internal/tools/registry.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log/slog"
 	"maps"
+	"slices"
 	"strings"
 	"sync"
 	"time"
@@ -222,18 +223,34 @@ func safeExecute(tool Tool, ctx context.Context, args map[string]any) (result *R
 
 // ProviderDefs returns tool definitions for LLM provider APIs.
 // Includes alias definitions (same params/description, alias name).
+// Results are sorted by tool name for deterministic ordering (prompt caching).
 func (r *Registry) ProviderDefs() []providers.ToolDefinition {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 
-	defs := make([]providers.ToolDefinition, 0, len(r.tools)+len(r.aliases))
-	for name, tool := range r.tools {
-		if r.disabled[name] {
-			continue
+	// Sort canonical tool names for deterministic ordering.
+	sortedNames := make([]string, 0, len(r.tools))
+	for name := range r.tools {
+		if !r.disabled[name] {
+			sortedNames = append(sortedNames, name)
 		}
-		defs = append(defs, ToProviderDef(tool))
 	}
-	for alias, canonical := range r.aliases {
+	slices.Sort(sortedNames)
+
+	defs := make([]providers.ToolDefinition, 0, len(sortedNames)+len(r.aliases))
+	for _, name := range sortedNames {
+		defs = append(defs, ToProviderDef(r.tools[name]))
+	}
+
+	// Sort alias names for deterministic ordering.
+	sortedAliases := make([]string, 0, len(r.aliases))
+	for alias := range r.aliases {
+		sortedAliases = append(sortedAliases, alias)
+	}
+	slices.Sort(sortedAliases)
+
+	for _, alias := range sortedAliases {
+		canonical := r.aliases[alias]
 		if r.disabled[canonical] {
 			continue
 		}
@@ -254,6 +271,8 @@ func (r *Registry) ProviderDefs() []providers.ToolDefinition {
 }
 
 // List returns all registered canonical tool names (excludes aliases).
+// Results are sorted lexicographically for deterministic ordering — critical
+// for LLM prompt caching (Anthropic/OpenAI cache by exact prefix match).
 func (r *Registry) List() []string {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
@@ -263,6 +282,7 @@ func (r *Registry) List() []string {
 			names = append(names, name)
 		}
 	}
+	slices.Sort(names)
 	return names
 }