diff --git a/config/initializers/config.rb b/config/initializers/config.rb
index 6103a8eb4..7980b0f08 100644
--- a/config/initializers/config.rb
+++ b/config/initializers/config.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'config'
+require 'yeti_config_loader'
 
 Config.class_eval do
   def self.setting_files(config_root, _env)
@@ -10,154 +11,9 @@ def self.setting_files(config_root, _env)
   end
 end
 
-Config.setup do |setup_config|
-  setup_config.const_name = 'YetiConfig'
-  setup_config.use_env = false
-
-  # Validate presence and type of specific config values.
-  # Check https://github.com/dry-rb/dry-validation for details.
-  setup_config.schema do
-    # config.validate_keys = true
-
-    required(:site_title).filled(:string)
-    required(:site_title_image).filled(:string)
-
-    required(:calls_monitoring).schema do
-      required(:write_account_stats).value(:bool?)
-      required(:write_gateway_stats).value(:bool?)
-      optional(:teardown_on_disabled_customer_auth).value(:bool?)
-      optional(:teardown_on_disabled_term_gw).value(:bool?)
-      optional(:teardown_on_disabled_orig_gw).value(:bool?)
-    end
-
-    required(:api).schema do
-      required(:token_lifetime).maybe(:int?)
-      optional(:customer).schema do
-        required(:token_lifetime).maybe(:int?)
-        optional(:call_jwt_lifetime).maybe(:int?)
-        optional(:call_jwt_secret).maybe(:string)
-        optional(:outgoing_cdr_hide_fields).array(:string)
-        optional(:outgoing_statistics_use_customer_duration).value(:bool?)
-        optional(:incoming_cdr_hide_fields).array(:string)
-        optional(:incoming_statistics_use_vendor_duration).value(:bool?)
-      end
-      optional(:system).schema do
-        optional(:token).maybe(:string)
-      end
-    end
-
-    optional(:rec_format).value(Dry::Types['string'].enum('wav', 'mp3'))
-
-    optional(:routing_simulation_default_interface).filled(:string)
-
-    required(:cdr_export).schema do
-      required(:dir_path).filled(:string)
-      required(:delete_url).filled(:string)
-    end
-
-    required(:role_policy).schema do
-      required(:when_no_config).value(Dry::Types['string'].enum('allow', 'disallow', 'raise'))
-      required(:when_no_policy_class).value(Dry::Types['string'].enum('allow', 'disallow', 'raise'))
-    end
-
-    required(:partition_remove_delay).hash do
-      required(:'cdr.cdr').maybe(:string, format?: /\A\d+ days\z/)
-      required(:'auth_log.auth_log').maybe(:string, format?: /\A\d+ days\z/)
-      required(:'rtp_statistics.rx_streams').maybe(:string, format?: /\A\d+ days\z/)
-      required(:'rtp_statistics.tx_streams').maybe(:string, format?: /\A\d+ days\z/)
-      required(:'logs.api_requests').maybe(:string, format?: /\A\d+ days\z/)
-    end
-
-    optional(:partition_detach_before_drop).filled(:bool)
-
-    optional(:disable_balance_notification_emails).filled(:bool)
-
-    required(:prometheus).schema do
-      required(:enabled).value(:bool?)
-      required(:host).maybe(:string)
-      required(:port).maybe(:int?)
-      optional(:default_labels).hash
-    end
-
-    required(:sentry).schema do
-      required(:enabled).value(:bool?)
-      required(:dsn).maybe(:string)
-      required(:node_name).filled(:string)
-      required(:environment).filled(:string)
-    end
-
-    optional(:telemetry).schema do
-      optional(:enabled).filled(:bool)
-    end
-
-    # Mounts the Doorkeeper OAuth provider (/oauth/authorize, /oauth/token,
-    # /oauth/register, /.well-known/oauth-authorization-server). Independent
-    # of MCP — can be enabled on its own to power SSO for other clients.
-    # Block AND `enabled` key are both optional; missing → treated as false.
-    optional(:oauth).schema do
-      optional(:enabled).value(:bool?)
-      optional(:issuer).maybe(:string)
-
-      optional(:oidc).schema do
-        optional(:enabled).value(:bool?)
-        optional(:signing_key_path).maybe(:string)
-      end
-    end
-
-    # Mounts /api/mcp. Requires oauth.enabled (MCP authenticates via OAuth
-    # bearer tokens); if oauth.enabled is false this flag has no effect.
-    # Block AND `enabled` key are both optional; missing → treated as false.
-    optional(:mcp).schema do
-      optional(:enabled).value(:bool?)
-    end
-
-    required(:versioning_disable_for_models).each(:string)
-
-    optional(:keep_expired_destinations_days)
-    optional(:keep_expired_dialpeers_days)
-    optional(:keep_balance_notifications_days)
-
-    optional(:cryptomus).schema do
-      optional(:api_key).maybe(:string)
-      optional(:merchant_id).maybe(:string)
-      optional(:base_url).maybe(:string)
-      optional(:url_callback).maybe(:string)
-      optional(:url_return).maybe(:string)
-    end
-
-    optional(:invoice).schema do
-      optional(:auto_approve).value(:bool)
-      optional(:pdf_converter).maybe(:string)
-      # External yeti-pdf render service. When configured (and a template has
-      # html_template) invoice PDFs are produced via yeti-pdf instead of the
-      # legacy ODT + pdf_converter path.
-      optional(:pdf_api).schema do
-        required(:base_url).filled(:string)
-        optional(:auth_token).maybe(:string)
-        optional(:timeout).maybe(:integer)
-        optional(:http_proxy).maybe(:string)
-        optional(:use_env_proxy).maybe(:bool?)
-      end
-    end
-    optional(:admin_ui).schema do
-      optional(:session_lifetime).maybe(:int?)
-      optional(:per_page).array(:integer)
-    end
-
-    optional(:ip_access).schema do
-      optional(:cdr_lookback_days).maybe(:int?)
-      optional(:lega_sip_min_ipv4_mask).maybe(:int?)
-      optional(:lega_sip_min_ipv6_mask).maybe(:int?)
-      optional(:lega_rtp_min_ipv4_mask).maybe(:int?)
-      optional(:lega_rtp_min_ipv6_mask).maybe(:int?)
-    end
-  end
-end
-
-Config.evaluate_erb_in_yaml = true
 begin
-  Config.load_and_set_settings(Config.setting_files(::Rails.root.join('config'), ::Rails.env))
-rescue Config::Validation::Error => e
+  YetiConfigLoader.call
+rescue YetiConfigLoader::Error => e
   warn e.message
   exit 1 # rubocop:disable Rails/Exit
 end
diff --git a/lib/prometheus/cdr_compaction_hook_collector.rb b/lib/prometheus/cdr_compaction_hook_collector.rb
index b9d4cb7e1..899fedebe 100644
--- a/lib/prometheus/cdr_compaction_hook_collector.rb
+++ b/lib/prometheus/cdr_compaction_hook_collector.rb
@@ -6,7 +6,9 @@ class CdrCompactionHookCollector < PrometheusExporter::Server::TypeCollector
   # Labels are resolved here instead of being taken from the payload, so that the counters can be
   # exported with a zero value from process start. Otherwise they only appear once the hook runs for
   # the first time, and an alert on "no executions" has no series to evaluate against.
-  def initialize(labels = CollectorLabels.call)
+  # Skipped when no cdr_compaction_hook is configured: the hook never runs, so a seeded zero would
+  # describe a switched-off feature forever.
+  def initialize(labels = CollectorLabels.call, seed_zeros: YetiConfig.cdr_compaction_hook.present?)
     super()
 
     @labels = labels
@@ -16,7 +18,7 @@ def initialize(labels = CollectorLabels.call)
       'errors' => PrometheusExporter::Metric::Counter.new('yeti_cdr_compaction_hook_errors', 'Sum of Yeti CDR Compaction Hook execution fails'),
       'duration' => PrometheusExporter::Metric::Counter.new('yeti_cdr_compaction_hook_duration', 'Sum of Yeti CDR Compaction Hook execution duration in seconds')
     }
-    @observers.each_value { |observer| observer.observe(0, @labels) }
+    @observers.each_value { |observer| observer.observe(0, @labels) } if seed_zeros
   end
 
   def type
diff --git a/lib/prometheus/collector_labels.rb b/lib/prometheus/collector_labels.rb
index da03b98d8..aa96ea901 100644
--- a/lib/prometheus/collector_labels.rb
+++ b/lib/prometheus/collector_labels.rb
@@ -12,16 +12,11 @@
 module CollectorLabels
   module_function
 
-  # @return [Hash<String, String>] empty when YetiConfig is unavailable or defines no default_labels
+  # @return [Hash<String, String>] empty when no default_labels are configured
   def call
     labels = PrometheusConfig.default_labels
     return {} if labels.nil?
 
     labels.to_h.to_h { |name, value| [name.to_s, value.to_s] }
-  rescue StandardError => e
-    # YetiConfig is absent when config/yeti_web.yml could not be loaded (see YetiConfigLoader).
-    # Unlabelled counters are strictly better than an exporter that refuses to start.
-    warn "CollectorLabels: #{e.class} #{e.message}"
-    {}
   end
 end
diff --git a/lib/prometheus/partition_remove_hook_collector.rb b/lib/prometheus/partition_remove_hook_collector.rb
index b84e3cf7c..415ba7611 100644
--- a/lib/prometheus/partition_remove_hook_collector.rb
+++ b/lib/prometheus/partition_remove_hook_collector.rb
@@ -6,7 +6,9 @@ class PartitionRemoveHookCollector < PrometheusExporter::Server::TypeCollector
   # Labels are resolved here instead of being taken from the payload, so that the counters can be
   # exported with a zero value from process start. Otherwise they only appear once the hook runs for
   # the first time, and an alert on "no executions" has no series to evaluate against.
-  def initialize(labels = CollectorLabels.call)
+  # Skipped when no partition_remove_hook is configured: the hook never runs, so a seeded zero would
+  # describe a switched-off feature forever.
+  def initialize(labels = CollectorLabels.call, seed_zeros: YetiConfig.partition_remove_hook.present?)
     super()
 
     @labels = labels
@@ -16,7 +18,7 @@ def initialize(labels = CollectorLabels.call)
       'errors' => PrometheusExporter::Metric::Counter.new('yeti_partition_removing_hook_errors', 'Sum of Yeti Partition Remove Hook execution fails'),
       'duration' => PrometheusExporter::Metric::Counter.new('yeti_partition_removing_hook_duration', 'Sum of Yeti Partition Remove Hook execution duration in seconds')
     }
-    @observers.each_value { |observer| observer.observe(0, @labels) }
+    @observers.each_value { |observer| observer.observe(0, @labels) } if seed_zeros
   end
 
   def type
diff --git a/lib/yeti_config_loader.rb b/lib/yeti_config_loader.rb
index ada914aa9..e3d6b9f04 100644
--- a/lib/yeti_config_loader.rb
+++ b/lib/yeti_config_loader.rb
@@ -1,35 +1,37 @@
 # frozen_string_literal: true
 
 require 'config'
+require_relative 'yeti_config_schema'
 
-# Loads config/yeti_web.yml into YetiConfig for processes that never boot Rails,
-# such as the standalone prometheus_exporter (see lib/prometheus_collectors.rb).
-#
-# The Rails application loads the same file, additionally validating it against a schema,
-# from config/initializers/config.rb. Schema validation is skipped here: the application
-# already fails loudly on an invalid config, and the exporter must keep exporting metrics
-# of every other yeti process regardless.
+# Loads config/yeti_web.yml into YetiConfig. Used both by the Rails application
+# (config/initializers/config.rb) and by processes that never boot Rails, such as the standalone
+# prometheus_exporter (lib/prometheus_collectors.rb), so that every reader of YetiConfig gets the
+# same file validated against the same schema.
 module YetiConfigLoader
+  class Error < StandardError; end
+
   CONFIG_PATH = File.expand_path('../config/yeti_web.yml', __dir__)
 
   module_function
 
   # @param path [String]
-  # @return [Boolean] whether YetiConfig is available afterwards
+  # @raise [YetiConfigLoader::Error] when the file is missing or does not satisfy YetiConfigSchema
   def call(path = CONFIG_PATH)
-    return true if defined?(::YetiConfig)
+    return if defined?(::YetiConfig)
+
+    # Config.load_and_set_settings accepts a missing path and defines an empty YetiConfig, so the
+    # absence has to be caught here. Checked before Config.setup to leave no global config applied.
+    raise Error, "config file not found: #{path}" unless File.exist?(path)
 
     Config.setup do |config|
       config.const_name = 'YetiConfig'
       config.use_env = false
+      YetiConfigSchema.apply(config)
     end
     Config.evaluate_erb_in_yaml = true
     Config.load_and_set_settings(path)
-    true
-  rescue StandardError => e
-    # A missing or broken config must not prevent the exporter from starting, otherwise every
-    # metric of every yeti process disappears at once.
-    warn "YetiConfigLoader: #{e.class} #{e.message}"
-    false
+    nil
+  rescue Config::Validation::Error => e
+    raise Error, "invalid config #{path}: #{e.message}"
   end
 end
diff --git a/lib/yeti_config_schema.rb b/lib/yeti_config_schema.rb
new file mode 100644
index 000000000..c7e54d2dd
--- /dev/null
+++ b/lib/yeti_config_schema.rb
@@ -0,0 +1,150 @@
+# frozen_string_literal: true
+
+require 'dry-validation'
+
+# Validation schema for config/yeti_web.yml. Lives here rather than in the Rails initializer so
+# that YetiConfigLoader can apply it for every process reading YetiConfig, Rails or not.
+# See https://github.com/dry-rb/dry-validation for the DSL.
+module YetiConfigSchema
+  module_function
+
+  # @param setup_config [Config::Options] the object yielded by Config.setup
+  def apply(setup_config)
+    setup_config.schema do
+      # config.validate_keys = true
+
+      required(:site_title).filled(:string)
+      required(:site_title_image).filled(:string)
+
+      required(:calls_monitoring).schema do
+        required(:write_account_stats).value(:bool?)
+        required(:write_gateway_stats).value(:bool?)
+        optional(:teardown_on_disabled_customer_auth).value(:bool?)
+        optional(:teardown_on_disabled_term_gw).value(:bool?)
+        optional(:teardown_on_disabled_orig_gw).value(:bool?)
+      end
+
+      required(:api).schema do
+        required(:token_lifetime).maybe(:int?)
+        optional(:customer).schema do
+          required(:token_lifetime).maybe(:int?)
+          optional(:call_jwt_lifetime).maybe(:int?)
+          optional(:call_jwt_secret).maybe(:string)
+          optional(:outgoing_cdr_hide_fields).array(:string)
+          optional(:outgoing_statistics_use_customer_duration).value(:bool?)
+          optional(:incoming_cdr_hide_fields).array(:string)
+          optional(:incoming_statistics_use_vendor_duration).value(:bool?)
+        end
+        optional(:system).schema do
+          optional(:token).maybe(:string)
+        end
+      end
+
+      optional(:rec_format).value(Dry::Types['string'].enum('wav', 'mp3'))
+
+      optional(:routing_simulation_default_interface).filled(:string)
+
+      required(:cdr_export).schema do
+        required(:dir_path).filled(:string)
+        required(:delete_url).filled(:string)
+      end
+
+      required(:role_policy).schema do
+        required(:when_no_config).value(Dry::Types['string'].enum('allow', 'disallow', 'raise'))
+        required(:when_no_policy_class).value(Dry::Types['string'].enum('allow', 'disallow', 'raise'))
+      end
+
+      required(:partition_remove_delay).hash do
+        required(:'cdr.cdr').maybe(:string, format?: /\A\d+ days\z/)
+        required(:'auth_log.auth_log').maybe(:string, format?: /\A\d+ days\z/)
+        required(:'rtp_statistics.rx_streams').maybe(:string, format?: /\A\d+ days\z/)
+        required(:'rtp_statistics.tx_streams').maybe(:string, format?: /\A\d+ days\z/)
+        required(:'logs.api_requests').maybe(:string, format?: /\A\d+ days\z/)
+      end
+
+      optional(:partition_detach_before_drop).filled(:bool)
+
+      optional(:disable_balance_notification_emails).filled(:bool)
+
+      required(:prometheus).schema do
+        required(:enabled).value(:bool?)
+        required(:host).maybe(:string)
+        required(:port).maybe(:int?)
+        optional(:default_labels).hash
+      end
+
+      required(:sentry).schema do
+        required(:enabled).value(:bool?)
+        required(:dsn).maybe(:string)
+        required(:node_name).filled(:string)
+        required(:environment).filled(:string)
+      end
+
+      optional(:telemetry).schema do
+        optional(:enabled).filled(:bool)
+      end
+
+      # Mounts the Doorkeeper OAuth provider (/oauth/authorize, /oauth/token,
+      # /oauth/register, /.well-known/oauth-authorization-server). Independent
+      # of MCP — can be enabled on its own to power SSO for other clients.
+      # Block AND `enabled` key are both optional; missing → treated as false.
+      optional(:oauth).schema do
+        optional(:enabled).value(:bool?)
+        optional(:issuer).maybe(:string)
+
+        optional(:oidc).schema do
+          optional(:enabled).value(:bool?)
+          optional(:signing_key_path).maybe(:string)
+        end
+      end
+
+      # Mounts /api/mcp. Requires oauth.enabled (MCP authenticates via OAuth
+      # bearer tokens); if oauth.enabled is false this flag has no effect.
+      # Block AND `enabled` key are both optional; missing → treated as false.
+      optional(:mcp).schema do
+        optional(:enabled).value(:bool?)
+      end
+
+      required(:versioning_disable_for_models).each(:string)
+
+      optional(:keep_expired_destinations_days)
+      optional(:keep_expired_dialpeers_days)
+      optional(:keep_balance_notifications_days)
+
+      optional(:cryptomus).schema do
+        optional(:api_key).maybe(:string)
+        optional(:merchant_id).maybe(:string)
+        optional(:base_url).maybe(:string)
+        optional(:url_callback).maybe(:string)
+        optional(:url_return).maybe(:string)
+      end
+
+      optional(:invoice).schema do
+        optional(:auto_approve).value(:bool)
+        optional(:pdf_converter).maybe(:string)
+        # External yeti-pdf render service. When configured (and a template has
+        # html_template) invoice PDFs are produced via yeti-pdf instead of the
+        # legacy ODT + pdf_converter path.
+        optional(:pdf_api).schema do
+          required(:base_url).filled(:string)
+          optional(:auth_token).maybe(:string)
+          optional(:timeout).maybe(:integer)
+          optional(:http_proxy).maybe(:string)
+          optional(:use_env_proxy).maybe(:bool?)
+        end
+      end
+      optional(:admin_ui).schema do
+        optional(:session_lifetime).maybe(:int?)
+        optional(:per_page).array(:integer)
+      end
+
+      optional(:ip_access).schema do
+        optional(:cdr_lookback_days).maybe(:int?)
+        optional(:lega_sip_min_ipv4_mask).maybe(:int?)
+        optional(:lega_sip_min_ipv6_mask).maybe(:int?)
+        optional(:lega_rtp_min_ipv4_mask).maybe(:int?)
+        optional(:lega_rtp_min_ipv6_mask).maybe(:int?)
+      end
+    end
+  end
+end
diff --git a/spec/lib/prometheus/cdr_compaction_hook_collector_spec.rb b/spec/lib/prometheus/cdr_compaction_hook_collector_spec.rb
index b80a495c4..eb4a37933 100644
--- a/spec/lib/prometheus/cdr_compaction_hook_collector_spec.rb
+++ b/spec/lib/prometheus/cdr_compaction_hook_collector_spec.rb
@@ -6,7 +6,8 @@
 RSpec.describe CdrCompactionHookCollector, '#metrics' do
   subject { described_instance.metrics.map(&:metric_text).compact_blank.map { |metrics| metrics.split("\n") }.flatten }
 
-  let(:described_instance) { described_class.new(labels) }
+  let(:described_instance) { described_class.new(labels, seed_zeros: seed_zeros) }
+  let(:seed_zeros) { true }
   let(:labels) { { 'host' => 'yeti-1' } }
   let(:data) { [metric_executions, metric_success, metric_errors, metric_duration] }
   let(:metric_executions) { { executions: 1 } }
@@ -85,11 +86,41 @@
   end
 
   describe 'default labels' do
-    subject { described_class.new }
+    subject { described_class.new(seed_zeros: true) }
 
     it 'resolves them from PrometheusConfig, matching the client custom_labels' do
       allow(PrometheusConfig).to receive(:default_labels).and_return({ host: :'yeti-2' })
       expect(subject.metrics.map(&:metric_text)).to include('yeti_cdr_compaction_hook_executions{host="yeti-2"} 0')
     end
   end
+
+  context 'when no cdr_compaction_hook is configured' do
+    let(:seed_zeros) { false }
+    let(:data) { [] }
+
+    it 'exports no series at all' do
+      expect(subject).to be_empty
+    end
+
+    it 'still records anything the job does report' do
+      described_instance.collect('executions' => 1)
+      expect(subject).to contain_exactly('yeti_cdr_compaction_hook_executions{host="yeti-1"} 1')
+    end
+  end
+
+  describe 'the zero seed' do
+    def seeded_series
+      described_class.new(labels).metrics.map(&:metric_text).compact_blank
+    end
+
+    it 'is skipped when the hook is not configured' do
+      allow(YetiConfig).to receive(:cdr_compaction_hook).and_return(nil)
+      expect(seeded_series).to be_empty
+    end
+
+    it 'happens when the hook is configured' do
+      allow(YetiConfig).to receive(:cdr_compaction_hook).and_return('/usr/local/bin/hook')
+      expect(seeded_series).not_to be_empty
+    end
+  end
 end
diff --git a/spec/lib/prometheus/collector_labels_spec.rb b/spec/lib/prometheus/collector_labels_spec.rb
index f41bd8dcb..2b773f331 100644
--- a/spec/lib/prometheus/collector_labels_spec.rb
+++ b/spec/lib/prometheus/collector_labels_spec.rb
@@ -26,13 +26,4 @@
 
     it { is_expected.to eq({}) }
   end
-
-  context 'when YetiConfig is unavailable' do
-    before { allow(PrometheusConfig).to receive(:default_labels).and_raise(NameError, 'uninitialized constant YetiConfig') }
-
-    it 'falls back to unlabelled metrics instead of preventing the exporter from starting' do
-      expect { subject }.to_not raise_error
-      expect(subject).to eq({})
-    end
-  end
 end
diff --git a/spec/lib/prometheus/partition_remove_hook_collector_spec.rb b/spec/lib/prometheus/partition_remove_hook_collector_spec.rb
index 2a5e189ed..32fda8666 100644
--- a/spec/lib/prometheus/partition_remove_hook_collector_spec.rb
+++ b/spec/lib/prometheus/partition_remove_hook_collector_spec.rb
@@ -6,7 +6,8 @@
 RSpec.describe PartitionRemoveHookCollector, '#metrics' do
   subject { described_instance.metrics.map(&:metric_text).compact_blank.map { |metrics| metrics.split("\n") }.flatten }
 
-  let(:described_instance) { described_class.new(labels) }
+  let(:described_instance) { described_class.new(labels, seed_zeros: seed_zeros) }
+  let(:seed_zeros) { true }
   let(:labels) { { 'host' => 'yeti-1' } }
   let(:data) { [metric_executions, metric_success, metric_errors, metric_duration] }
   let(:metric_executions) { { executions: 1 } }
@@ -85,11 +86,41 @@
   end
 
   describe 'default labels' do
-    subject { described_class.new }
+    subject { described_class.new(seed_zeros: true) }
 
     it 'resolves them from PrometheusConfig, matching the client custom_labels' do
       allow(PrometheusConfig).to receive(:default_labels).and_return({ host: :'yeti-2' })
       expect(subject.metrics.map(&:metric_text)).to include('yeti_partition_removing_hook_executions{host="yeti-2"} 0')
     end
   end
+
+  context 'when no partition_remove_hook is configured' do
+    let(:seed_zeros) { false }
+    let(:data) { [] }
+
+    it 'exports no series at all' do
+      expect(subject).to be_empty
+    end
+
+    it 'still records anything the job does report' do
+      described_instance.collect('executions' => 1)
+      expect(subject).to contain_exactly('yeti_partition_removing_hook_executions{host="yeti-1"} 1')
+    end
+  end
+
+  describe 'the zero seed' do
+    def seeded_series
+      described_class.new(labels).metrics.map(&:metric_text).compact_blank
+    end
+
+    it 'is skipped when the hook is not configured' do
+      allow(YetiConfig).to receive(:partition_remove_hook).and_return(nil)
+      expect(seeded_series).to be_empty
+    end
+
+    it 'happens when the hook is configured' do
+      allow(YetiConfig).to receive(:partition_remove_hook).and_return('/usr/local/bin/hook')
+      expect(seeded_series).not_to be_empty
+    end
+  end
 end
diff --git a/spec/lib/yeti_config_loader_spec.rb b/spec/lib/yeti_config_loader_spec.rb
new file mode 100644
index 000000000..c9f03abdc
--- /dev/null
+++ b/spec/lib/yeti_config_loader_spec.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative Rails.root.join('lib/yeti_config_loader')
+
+RSpec.describe YetiConfigLoader, '.call' do
+  it 'does nothing when YetiConfig is already loaded' do
+    expect { described_class.call('/nonexistent/yeti_web.yml') }.not_to raise_error
+  end
+
+  context 'when YetiConfig has not been loaded yet' do
+    before { hide_const('YetiConfig') }
+
+    it 'raises rather than starting without a config' do
+      expect { described_class.call('/nonexistent/yeti_web.yml') }
+        .to raise_error(YetiConfigLoader::Error, %r{config file not found: /nonexistent/yeti_web.yml})
+    end
+
+    it 'raises before touching the global Config setup' do
+      expect(Config).not_to receive(:setup)
+      expect { described_class.call('/nonexistent/yeti_web.yml') }.to raise_error(YetiConfigLoader::Error)
+    end
+
+    it 'reports an invalid config as its own error, not the gem class' do
+      allow(Config).to receive(:load_and_set_settings)
+        .and_raise(Config::Validation::Error, 'site_title: must be a string')
+
+      expect { described_class.call }
+        .to raise_error(YetiConfigLoader::Error, /invalid config .*yeti_web\.yml: site_title: must be a string/)
+    end
+  end
+end