Add HTTP size limits

internal/config/config.go

@@ -40,8 +40,11 @@ type Config struct {
 }
 
 type ServerConfig struct {
-	Addr         string `yaml:"addr"`
-	ArtifactRoot string `yaml:"artifact_root"`
+	Addr             string `yaml:"addr"`
+	ArtifactRoot     string `yaml:"artifact_root"`
+	MaxRequestBytes  *int64 `yaml:"max_request_bytes"`
+	MaxArtifactBytes *int64 `yaml:"max_artifact_bytes"`
+	MaxResponseBytes *int64 `yaml:"max_response_bytes"`
 }
 
 type DefaultsConfig struct {
@@ -55,17 +58,23 @@ type AppSettings struct {
 	SchemaDir           string
 	ServerAddr          string
 	ArtifactRoot        string
+	MaxRequestBytes     int64
+	MaxArtifactBytes    int64
+	MaxResponseBytes    int64
 	DefaultRenderFormat renderformat.PreparedRunOutputFormat
 }
 
 // CLIOverrides can be applied after config load to enforce precedence.
 type CLIOverrides struct {
-	PromptDir    string
-	ProfileDir   string
-	SchemaDir    string
-	ServerAddr   string
-	ArtifactRoot string
-	RenderFormat string
+	PromptDir        string
+	ProfileDir       string
+	SchemaDir        string
+	ServerAddr       string
+	ArtifactRoot     string
+	MaxRequestBytes  *int64
+	MaxArtifactBytes *int64
+	MaxResponseBytes *int64
+	RenderFormat     string
 }
 
 // BuiltInDefaults returns compile-time application defaults.
@@ -73,6 +82,9 @@ func BuiltInDefaults() AppSettings {
 	return AppSettings{
 		SchemaDir:           defaults.SchemaDirDefault,
 		ServerAddr:          defaults.HTTPAddrDefault,
+		MaxRequestBytes:     defaults.HTTPMaxRequestBytesDefault,
+		MaxArtifactBytes:    defaults.HTTPMaxArtifactBytesDefault,
+		MaxResponseBytes:    defaults.HTTPMaxResponseBytesDefault,
 		DefaultRenderFormat: renderformat.DefaultPreparedRunOutputFormat,
 	}
 }
@@ -148,6 +160,24 @@ func ApplyCLIOverrides(base AppSettings, overrides CLIOverrides) (AppSettings, e
 	if v := strings.TrimSpace(overrides.ArtifactRoot); v != "" {
 		out.ArtifactRoot = filepath.Clean(v)
 	}
+	if overrides.MaxRequestBytes != nil {
+		if *overrides.MaxRequestBytes < 0 {
+			return AppSettings{}, fmt.Errorf("%w: server.max_request_bytes must be greater than or equal to 0", ErrInvalidConfig)
+		}
+		out.MaxRequestBytes = *overrides.MaxRequestBytes
+	}
+	if overrides.MaxArtifactBytes != nil {
+		if *overrides.MaxArtifactBytes < 0 {
+			return AppSettings{}, fmt.Errorf("%w: server.max_artifact_bytes must be greater than or equal to 0", ErrInvalidConfig)
+		}
+		out.MaxArtifactBytes = *overrides.MaxArtifactBytes
+	}
+	if overrides.MaxResponseBytes != nil {
+		if *overrides.MaxResponseBytes < 0 {
+			return AppSettings{}, fmt.Errorf("%w: server.max_response_bytes must be greater than or equal to 0", ErrInvalidConfig)
+		}
+		out.MaxResponseBytes = *overrides.MaxResponseBytes
+	}
 	if rawFormat := strings.TrimSpace(overrides.RenderFormat); rawFormat != "" {
 		parsed, err := renderformat.ParsePreparedRunOutputFormat(rawFormat)
 		if err != nil {
@@ -190,6 +220,24 @@ func applyConfig(base AppSettings, cfg Config) (AppSettings, error) {
 	if v := strings.TrimSpace(cfg.Server.ArtifactRoot); v != "" {
 		out.ArtifactRoot = filepath.Clean(v)
 	}
+	if cfg.Server.MaxRequestBytes != nil {
+		if *cfg.Server.MaxRequestBytes < 0 {
+			return AppSettings{}, fmt.Errorf("%w: server.max_request_bytes must be greater than or equal to 0", ErrInvalidConfig)
+		}
+		out.MaxRequestBytes = *cfg.Server.MaxRequestBytes
+	}
+	if cfg.Server.MaxArtifactBytes != nil {
+		if *cfg.Server.MaxArtifactBytes < 0 {
+			return AppSettings{}, fmt.Errorf("%w: server.max_artifact_bytes must be greater than or equal to 0", ErrInvalidConfig)
+		}
+		out.MaxArtifactBytes = *cfg.Server.MaxArtifactBytes
+	}
+	if cfg.Server.MaxResponseBytes != nil {
+		if *cfg.Server.MaxResponseBytes < 0 {
+			return AppSettings{}, fmt.Errorf("%w: server.max_response_bytes must be greater than or equal to 0", ErrInvalidConfig)
+		}
+		out.MaxResponseBytes = *cfg.Server.MaxResponseBytes
+	}
 	if rawFormat := strings.TrimSpace(cfg.Defaults.RenderFormat); rawFormat != "" {
 		parsed, err := renderformat.ParsePreparedRunOutputFormat(rawFormat)
 		if err != nil {