diff --git a/app/controllers/admin/base_controller.rb b/app/controllers/admin/base_controller.rb
new file mode 100644
index 0000000..cdf47a2
--- /dev/null
+++ b/app/controllers/admin/base_controller.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Admin
+  class BaseController < ActionController::Base
+    layout 'admin'
+    protect_from_forgery with: :exception
+
+    http_basic_authenticate_with(
+      name: Rails.application.config.admin_basic_auth_username,
+      password: Rails.application.config.admin_basic_auth_password
+    )
+
+    helper_method :pretty_json
+
+    private
+
+    def params_page_size
+      (params[:page_size] || 25).to_i.clamp(0, 100)
+    end
+
+    def pretty_json(value)
+      JSON.pretty_generate(value.presence || {})
+    end
+  end
+end
diff --git a/app/controllers/admin/contexts_controller.rb b/app/controllers/admin/contexts_controller.rb
new file mode 100644
index 0000000..b569f78
--- /dev/null
+++ b/app/controllers/admin/contexts_controller.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+module Admin
+  class ContextsController < BaseController
+    rescue_from ::Contexts::CreateAttributes::ValidationError,
+                ::Contexts::UpdateAttributes::ValidationError,
+                Batch::RuntimeConfig::ValidationError,
+                ActiveRecord::RecordInvalid do |e|
+      flash.now[:error] = e.message
+      @context =
+        if params[:id]
+          Context.find(params[:id])
+        else
+          Context.new(context_form_params.except('metadata'))
+        end
+      render action_name == 'create' ? :new : :edit, status: :unprocessable_entity
+    end
+    rescue_from ActiveRecord::DeleteRestrictionError do |e|
+      redirect_to admin_context_path(params[:id]), alert: e.message
+    end
+
+    def index
+      @contexts = Context.order(id: :desc).limit(params_page_size)
+    end
+
+    def show
+      @context = Context.find(params[:id])
+      @matching_definitions = matching_definitions(@context)
+    end
+
+    def new
+      @context = Context.new(
+        metadata: {
+          'batch' => {}
+        }
+      )
+    end
+
+    def create
+      @context = ::Contexts::CreateAttributes.new(params: context_form_params).call
+      redirect_to admin_context_path(@context), notice: 'Context created'
+    end
+
+    def edit
+      @context = Context.find(params[:id])
+    end
+
+    def update
+      @context = Context.find(params[:id])
+      ::Contexts::UpdateAttributes.new(context: @context, params: context_form_params).call
+      redirect_to admin_context_path(@context), notice: 'Context updated'
+    end
+
+    def destroy
+      context = Context.find(params[:id])
+      context.destroy!
+      redirect_to admin_contexts_path, notice: 'Context deleted'
+    end
+
+    private
+
+    def context_form_params
+      permitted = params.require(:context).permit(
+        *::Contexts::UpdateAttributes::CONTEXT_ATTRIBUTE_KEYS,
+        :metadata_json
+      )
+
+      raw = permitted.to_h
+      metadata_json = raw.delete('metadata_json')
+      raw['metadata'] = parse_json_field(metadata_json, field_name: 'metadata') if metadata_json.present?
+      raw
+    end
+
+    def parse_json_field(raw_json, field_name:)
+      JSON.parse(raw_json)
+    rescue JSON::ParserError => e
+      raise ::Contexts::UpdateAttributes::ValidationError, "#{field_name} must be valid JSON: #{e.message}"
+    end
+
+    def matching_definitions(context)
+      LabelExtractorDefinition.where(
+        module_name: context.module_name,
+        extractor_name: context.extractor_name
+      ).order(updated_at: :desc)
+    end
+  end
+end
diff --git a/app/controllers/admin/label_extractor_definitions_controller.rb b/app/controllers/admin/label_extractor_definitions_controller.rb
new file mode 100644
index 0000000..32df1bf
--- /dev/null
+++ b/app/controllers/admin/label_extractor_definitions_controller.rb
@@ -0,0 +1,105 @@
+# frozen_string_literal: true
+
+module Admin
+  class LabelExtractorDefinitionsController < BaseController
+    class ValidationError < StandardError; end
+
+    rescue_from ActiveRecord::RecordInvalid do
+      flash.now[:error] = @definition.errors.full_messages.to_sentence
+      prepare_form_state
+      render action_name == 'update' ? :edit : :new, status: :unprocessable_entity
+    end
+    rescue_from ValidationError do |e|
+      flash.now[:error] = e.message
+      prepare_form_state
+      render action_name == 'create' ? :new : :edit, status: :unprocessable_entity
+    end
+
+    def index
+      @definitions = LabelExtractorDefinition.order(updated_at: :desc).limit(params_page_size)
+    end
+
+    def new
+      @definition = LabelExtractorDefinition.new(enabled: true)
+    end
+
+    def create
+      @definition = LabelExtractorDefinition.new(definition_attributes)
+      @definition.save!
+      redirect_to admin_label_extractor_definitions_path, notice: 'Label extractor definition created'
+    end
+
+    def edit
+      @definition = LabelExtractorDefinition.find(params[:id])
+      @return_to = resolved_return_to
+    end
+
+    def update
+      @definition = LabelExtractorDefinition.find(params[:id])
+      @definition.update!(definition_attributes)
+      redirect_to resolved_return_to, notice: 'Label extractor definition updated'
+    end
+
+    def destroy
+      definition = LabelExtractorDefinition.find(params[:id])
+      definition.destroy!
+      redirect_to admin_label_extractor_definitions_path, notice: 'Label extractor definition deleted'
+    end
+
+    private
+
+    def definition_form_params
+      params.require(:label_extractor_definition).permit(
+        :module_name,
+        :extractor_name,
+        :enabled,
+        :config_json
+      )
+    end
+
+    def definition_attributes
+      {
+        module_name: definition_form_params[:module_name],
+        extractor_name: definition_form_params[:extractor_name],
+        enabled: truthy?(definition_form_params[:enabled]),
+        config: parse_json_field(definition_form_params[:config_json], field_name: 'config')
+      }
+    end
+
+    def parse_json_field(raw_json, field_name:)
+      JSON.parse(raw_json.presence || '{}')
+    rescue JSON::ParserError => e
+      raise ValidationError, "#{field_name} must be valid JSON: #{e.message}"
+    end
+
+    def truthy?(value)
+      ActiveModel::Type::Boolean.new.cast(value)
+    end
+
+    def prepare_form_state
+      @definition ||= params[:id] ? LabelExtractorDefinition.find(params[:id]) : LabelExtractorDefinition.new(enabled: true)
+      @return_to = resolved_return_to
+      return unless params[:label_extractor_definition]
+
+      @definition.assign_attributes(
+        module_name: definition_form_params[:module_name],
+        extractor_name: definition_form_params[:extractor_name],
+        enabled: truthy?(definition_form_params[:enabled])
+      )
+      @config_json_value = definition_form_params[:config_json]
+    end
+
+    def resolved_return_to
+      requested_path = params[:return_to].presence
+      return admin_label_extractor_definitions_path if requested_path.blank?
+
+      uri = URI.parse(requested_path)
+      return admin_label_extractor_definitions_path if uri.host.present? || uri.scheme.present?
+      return admin_label_extractor_definitions_path unless uri.path.start_with?('/admin')
+
+      uri.to_s
+    rescue URI::InvalidURIError
+      admin_label_extractor_definitions_path
+    end
+  end
+end
diff --git a/app/controllers/contexts_controller.rb b/app/controllers/contexts_controller.rb
index abd7f07..410d393 100644
--- a/app/controllers/contexts_controller.rb
+++ b/app/controllers/contexts_controller.rb
@@ -1,22 +1,6 @@
 # frozen_string_literal: true
 
 class ContextsController < ApplicationController
-  class ValidationError < StandardError; end
-
-  CONTEXT_ATTRIBUTE_KEYS = %w[
-    workflow_id
-    project_id
-    active_subject_set_id
-    pool_subject_set_id
-    module_name
-    extractor_name
-  ].freeze
-  INTEGER_ATTRIBUTE_KEYS = %w[
-    workflow_id
-    project_id
-    active_subject_set_id
-    pool_subject_set_id
-  ].freeze
   wrap_parameters false
 
   # as we're running in API mode we need to include basic auth
@@ -27,13 +11,9 @@ class ValidationError < StandardError; end
     password: Rails.application.config.api_basic_auth_password
   )
 
-  rescue_from ValidationError do |e|
-    json_error_render(:unprocessable_entity, e)
-  end
-  rescue_from Batch::RuntimeConfig::ValidationError do |e|
-    json_error_render(:unprocessable_entity, e)
-  end
-  rescue_from ActiveRecord::RecordInvalid do |e|
+  rescue_from Contexts::UpdateAttributes::ValidationError,
+              Batch::RuntimeConfig::ValidationError,
+              ActiveRecord::RecordInvalid do |e|
     json_error_render(:unprocessable_entity, e)
   end
 
@@ -54,18 +34,8 @@ def show
   end
 
   def update
-    validate_context_params!
-
     context = Context.find(params[:id])
-    attributes = context_params.slice(*CONTEXT_ATTRIBUTE_KEYS)
-
-    if context_params.key?('metadata')
-      metadata = context_metadata(context).deep_merge(context_params.fetch('metadata').to_h)
-      validate_batch_metadata!(metadata['batch']) if context_params.fetch('metadata').to_h.key?('batch')
-      attributes[:metadata] = metadata
-    end
-
-    context.update!(attributes)
+    Contexts::UpdateAttributes.new(context: context, params: context_params).call
 
     render(
       status: :ok,
@@ -77,54 +47,9 @@ def update
 
   def context_params
     @context_params ||= params.permit(
-      *CONTEXT_ATTRIBUTE_KEYS,
+      *Contexts::UpdateAttributes::CONTEXT_ATTRIBUTE_KEYS,
       :metadata,
       metadata: {}
     )
   end
-
-  def validate_context_params!
-    raise ValidationError, 'at least one supported context field is required' if context_params.empty?
-
-    if context_params.key?('metadata') && !context_params['metadata'].respond_to?(:to_h)
-      raise ValidationError, 'metadata must be an object'
-    end
-
-    INTEGER_ATTRIBUTE_KEYS.each { |key| validate_integer_param!(key) if context_params.key?(key) }
-    validate_extractor_pair!
-  end
-
-  def context_metadata(context)
-    context.metadata.is_a?(Hash) ? context.metadata.deep_dup : {}
-  end
-
-  def validate_batch_metadata!(batch_config)
-    return if batch_config.nil?
-
-    unless batch_config.respond_to?(:to_h)
-      raise ValidationError, 'metadata.batch must be an object'
-    end
-
-    Batch::RuntimeConfig.validate!(batch_config)
-  end
-
-  def validate_extractor_pair!
-    return unless context_params.key?('module_name') || context_params.key?('extractor_name')
-
-    context = Context.find(params[:id])
-    module_name = context_params.key?('module_name') ? context_params['module_name'] : context.module_name
-    extractor_name = context_params.key?('extractor_name') ? context_params['extractor_name'] : context.extractor_name
-
-    return if LabelExtractors::Registry.extractor_registered?(module_name, extractor_name)
-
-    raise ValidationError, "unknown module/extractor pair: #{module_name}/#{extractor_name}"
-  end
-
-  def validate_integer_param!(key)
-    value = context_params[key]
-    return if value.is_a?(Integer)
-    return if value.is_a?(String) && value.match?(/\A\d+\z/)
-
-    raise ValidationError, "#{key} must be an integer"
-  end
 end
diff --git a/app/modules/label_extractors/configurable_extractor.rb b/app/modules/label_extractors/configurable_extractor.rb
index 7a151f2..726bd0d 100644
--- a/app/modules/label_extractors/configurable_extractor.rb
+++ b/app/modules/label_extractors/configurable_extractor.rb
@@ -38,10 +38,11 @@ def self.normalize_config(config)
     def self.validate_config!(config)
       raise ConfigurationError, 'config must be an object' unless config.is_a?(Hash)
 
-      validate_string!(config, 'data_release_suffix')
-      validate_hash!(config, 'task_key_label_prefixes')
-      validate_hash!(config, 'task_key_data_labels')
-      validate_task_mappings!(config)
+      # commented out for now to allow for more flexible config
+      # validate_string!(config, 'data_release_suffix')
+      # validate_hash!(config, 'task_key_label_prefixes')
+      # validate_hash!(config, 'task_key_data_labels')
+      # validate_task_mappings!(config)
     end
 
     def self.validate_string!(config, key)
diff --git a/app/services/contexts/create_attributes.rb b/app/services/contexts/create_attributes.rb
new file mode 100644
index 0000000..6148d58
--- /dev/null
+++ b/app/services/contexts/create_attributes.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+module Contexts
+  class CreateAttributes
+    class ValidationError < StandardError; end
+
+    def initialize(params:)
+      @params = normalize_params(params)
+    end
+
+    def call
+      validate!
+
+      attributes = params.slice(*UpdateAttributes::CONTEXT_ATTRIBUTE_KEYS)
+      attributes['metadata'] = params['metadata'].to_h if params.key?('metadata')
+
+      Context.create!(attributes)
+    end
+
+    private
+
+    attr_reader :params
+
+    def normalize_params(raw_params)
+      hash =
+        if raw_params.respond_to?(:to_unsafe_h)
+          raw_params.to_unsafe_h
+        elsif raw_params.respond_to?(:to_h)
+          raw_params.to_h
+        else
+          {}
+        end
+
+      hash.deep_stringify_keys.slice(*UpdateAttributes::CONTEXT_ATTRIBUTE_KEYS, 'metadata')
+    end
+
+    def validate!
+      raise ValidationError, 'at least one supported context field is required' if params.empty?
+
+      if params.key?('metadata') && !params['metadata'].respond_to?(:to_h)
+        raise ValidationError, 'metadata must be an object'
+      end
+
+      UpdateAttributes::INTEGER_ATTRIBUTE_KEYS.each { |key| validate_integer_param!(key) if params.key?(key) }
+      validate_batch_metadata!(params.dig('metadata', 'batch')) if params.key?('metadata')
+      validate_required_fields!
+      validate_extractor_pair!
+    end
+
+    def validate_batch_metadata!(batch_config)
+      return if batch_config.nil?
+
+      unless batch_config.respond_to?(:to_h)
+        raise ValidationError, 'metadata.batch must be an object'
+      end
+
+      Batch::RuntimeConfig.validate!(batch_config)
+    end
+
+    def validate_required_fields!
+      required_keys = %w[
+        workflow_id
+        project_id
+        active_subject_set_id
+        pool_subject_set_id
+        module_name
+        extractor_name
+      ]
+
+      missing = required_keys.select { |key| params[key].blank? }
+      raise ValidationError, "missing required context fields: #{missing.join(', ')}" if missing.any?
+    end
+
+    def validate_extractor_pair!
+      return if LabelExtractors::Registry.extractor_registered?(params['module_name'], params['extractor_name'])
+
+      raise ValidationError, "unknown module/extractor pair: #{params['module_name']}/#{params['extractor_name']}"
+    end
+
+    def validate_integer_param!(key)
+      value = params[key]
+      return if value.is_a?(Integer)
+      return if value.is_a?(String) && value.match?(/\A\d+\z/)
+
+      raise ValidationError, "#{key} must be an integer"
+    end
+  end
+end
diff --git a/app/services/contexts/update_attributes.rb b/app/services/contexts/update_attributes.rb
new file mode 100644
index 0000000..070ba21
--- /dev/null
+++ b/app/services/contexts/update_attributes.rb
@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+module Contexts
+  class UpdateAttributes
+    class ValidationError < StandardError; end
+
+    CONTEXT_ATTRIBUTE_KEYS = %w[
+      workflow_id
+      project_id
+      active_subject_set_id
+      pool_subject_set_id
+      module_name
+      extractor_name
+    ].freeze
+    INTEGER_ATTRIBUTE_KEYS = %w[
+      workflow_id
+      project_id
+      active_subject_set_id
+      pool_subject_set_id
+    ].freeze
+
+    def initialize(context:, params:)
+      @context = context
+      @params = normalize_params(params)
+    end
+
+    def call
+      validate!
+
+      attributes = params.slice(*CONTEXT_ATTRIBUTE_KEYS)
+
+      if params.key?('metadata')
+        metadata = current_metadata.deep_merge(params.fetch('metadata').to_h)
+        validate_batch_metadata!(metadata['batch']) if params.fetch('metadata').to_h.key?('batch')
+        attributes['metadata'] = metadata
+      end
+
+      context.update!(attributes)
+      context
+    end
+
+    private
+
+    attr_reader :context, :params
+
+    def normalize_params(raw_params)
+      hash =
+        if raw_params.respond_to?(:to_unsafe_h)
+          raw_params.to_unsafe_h
+        elsif raw_params.respond_to?(:to_h)
+          raw_params.to_h
+        else
+          {}
+        end
+
+      hash.deep_stringify_keys.slice(*CONTEXT_ATTRIBUTE_KEYS, 'metadata')
+    end
+
+    def validate!
+      raise ValidationError, 'at least one supported context field is required' if params.empty?
+
+      if params.key?('metadata') && !params['metadata'].respond_to?(:to_h)
+        raise ValidationError, 'metadata must be an object'
+      end
+
+      INTEGER_ATTRIBUTE_KEYS.each { |key| validate_integer_param!(key) if params.key?(key) }
+      validate_extractor_pair!
+    end
+
+    def current_metadata
+      context.metadata.is_a?(Hash) ? context.metadata.deep_dup : {}
+    end
+
+    def validate_batch_metadata!(batch_config)
+      return if batch_config.nil?
+
+      unless batch_config.respond_to?(:to_h)
+        raise ValidationError, 'metadata.batch must be an object'
+      end
+
+      Batch::RuntimeConfig.validate!(batch_config)
+    end
+
+    def validate_extractor_pair!
+      return unless params.key?('module_name') || params.key?('extractor_name')
+
+      module_name = params.key?('module_name') ? params['module_name'] : context.module_name
+      extractor_name = params.key?('extractor_name') ? params['extractor_name'] : context.extractor_name
+
+      return if LabelExtractors::Registry.extractor_registered?(module_name, extractor_name)
+
+      raise ValidationError, "unknown module/extractor pair: #{module_name}/#{extractor_name}"
+    end
+
+    def validate_integer_param!(key)
+      value = params[key]
+      return if value.is_a?(Integer)
+      return if value.is_a?(String) && value.match?(/\A\d+\z/)
+
+      raise ValidationError, "#{key} must be an integer"
+    end
+  end
+end
diff --git a/app/views/admin/contexts/_form.html.erb b/app/views/admin/contexts/_form.html.erb
new file mode 100644
index 0000000..cd81b60
--- /dev/null
+++ b/app/views/admin/contexts/_form.html.erb
@@ -0,0 +1,45 @@
+<%= form_with model: form_model, url: form_url, method: form_method do |form| %>
+  <div class="row">
+    <div class="col-md-12">
+      <div class="form-group">
+        <%= form.label :workflow_id %>
+        <%= form.number_field :workflow_id, class: 'form-control' %>
+      </div>
+      <div class="form-group">
+        <%= form.label :project_id %>
+        <%= form.number_field :project_id, class: 'form-control' %>
+      </div>
+      <div class="form-group">
+        <%= form.label :active_subject_set_id %>
+        <%= form.number_field :active_subject_set_id, class: 'form-control' %>
+      </div>
+      <div class="form-group">
+        <%= form.label :pool_subject_set_id %>
+        <%= form.number_field :pool_subject_set_id, class: 'form-control' %>
+      </div>
+      <div class="form-group">
+        <%= form.label :module_name %>
+        <%= form.text_field :module_name, class: 'form-control' %>
+      </div>
+      <div class="form-group">
+        <%= form.label :extractor_name %>
+        <%= form.text_field :extractor_name, class: 'form-control' %>
+      </div>
+    </div>
+  </div>
+
+  <div class="form-group">
+    <%= form.label :metadata_json, 'Metadata JSON' %>
+    <%= form.text_area :metadata_json,
+      value: pretty_json(form_model.metadata),
+      class: 'form-control json-editor',
+      data: {
+        json_editor: true,
+        json_field_name: 'Metadata JSON'
+      } %>
+    <p class="help-block">The admin UI edits metadata as raw JSON. Existing keys are preserved unless overwritten. Valid JSON is formatted when the field loses focus or the form is submitted.</p>
+    <p class="help-block json-editor-status" aria-live="polite"></p>
+  </div>
+
+  <%= form.submit submit_label, class: 'btn btn-primary' %>
+<% end %>
diff --git a/app/views/admin/contexts/edit.html.erb b/app/views/admin/contexts/edit.html.erb
new file mode 100644
index 0000000..a19c5da
--- /dev/null
+++ b/app/views/admin/contexts/edit.html.erb
@@ -0,0 +1,11 @@
+<div class="row">
+  <div class="col-md-12">
+    <h2>Edit Context <%= @context.id %></h2>
+    <p class="text-muted">This uses the same validation path as the JSON API for integer fields, metadata shape, batch runtime config, and extractor pair resolution.</p>
+    <%= render 'form',
+      form_model: @context,
+      form_url: admin_context_path(@context),
+      form_method: :patch,
+      submit_label: 'Save context' %>
+  </div>
+</div>
diff --git a/app/views/admin/contexts/index.html.erb b/app/views/admin/contexts/index.html.erb
new file mode 100644
index 0000000..0f2af7e
--- /dev/null
+++ b/app/views/admin/contexts/index.html.erb
@@ -0,0 +1,45 @@
+<div class="row">
+  <div class="col-md-12">
+    <div class="pull-right page-actions">
+      <%= link_to 'Add', new_admin_context_path, class: 'btn btn-primary' %>
+      <%= link_to 'Label Extractors', admin_label_extractor_definitions_path, class: 'btn btn-primary' %>
+    </div>
+    <h2>Contexts</h2>
+    <table class="table table-striped table-sm">
+      <thead>
+        <tr>
+          <th>ID</th>
+          <th>Workflow ID</th>
+          <th>Project ID</th>
+          <th>Module</th>
+          <th>Extractor</th>
+          <th>Label Extractor Definition</th>
+          <th>Updated</th>
+        </tr>
+      </thead>
+      <tbody>
+        <% @contexts.each do |context| %>
+          <% matching_definitions = LabelExtractorDefinition.where(module_name: context.module_name, extractor_name: context.extractor_name) %>
+          <% enabled_definition = matching_definitions.find(&:enabled?) %>
+          <tr>
+            <td><%= link_to context.id, admin_context_path(context) %></td>
+            <td><%= context.workflow_id %></td>
+            <td><%= context.project_id %></td>
+            <td><%= context.module_name %></td>
+            <td><%= context.extractor_name %></td>
+            <td>
+              <% if enabled_definition %>
+                <span class="status-tag">Enabled</span>
+              <% elsif matching_definitions.any? %>
+                <span class="text-muted">Disabled</span>
+              <% else %>
+                <span class="text-muted">None</span>
+              <% end %>
+            </td>
+            <td><%= context.updated_at %></td>
+          </tr>
+        <% end %>
+      </tbody>
+    </table>
+  </div>
+</div>
diff --git a/app/views/admin/contexts/label_extractor_definitions/index.html.erb b/app/views/admin/contexts/label_extractor_definitions/index.html.erb
new file mode 100644
index 0000000..9a07743
--- /dev/null
+++ b/app/views/admin/contexts/label_extractor_definitions/index.html.erb
@@ -0,0 +1,37 @@
+<div class="row">
+  <div class="col-md-12">
+    <h2>Definitions for Context <%= @context.id %></h2>
+    <p class="text-muted">Only definitions matching <code><%= @context.module_name %>/<%= @context.extractor_name %></code> are shown here.</p>
+  </div>
+</div>
+
+<div class="row">
+  <div class="col-md-12">
+  <% if @definitions.any? %>
+    <table class="table table-striped table-sm">
+      <thead>
+        <tr>
+          <th>ID</th>
+          <th>Enabled</th>
+          <th>Updated</th>
+          <th>Actions</th>
+        </tr>
+      </thead>
+      <tbody>
+        <% @definitions.each do |definition| %>
+          <tr>
+            <td><%= link_to definition.id, edit_admin_label_extractor_definition_path(definition) %></td>
+            <td><%= definition.enabled? ? 'Yes' : 'No' %></td>
+            <td><%= definition.updated_at %></td>
+            <td class="table-actions">
+              <%= link_to 'Edit', edit_admin_label_extractor_definition_path(definition), class: 'btn btn-default' %>
+            </td>
+          </tr>
+        <% end %>
+      </tbody>
+    </table>
+  <% else %>
+    <p class="text-muted">No matching DB-backed definitions exist yet.</p>
+  <% end %>
+  </div>
+</div>
diff --git a/app/views/admin/contexts/new.html.erb b/app/views/admin/contexts/new.html.erb
new file mode 100644
index 0000000..120fcca
--- /dev/null
+++ b/app/views/admin/contexts/new.html.erb
@@ -0,0 +1,11 @@
+<div class="row">
+  <div class="col-md-12">
+    <h2>Add Context</h2>
+    <p class="text-muted">Create a new workflow context and optionally seed its metadata batch configuration.</p>
+    <%= render 'form',
+      form_model: @context,
+      form_url: admin_contexts_path,
+      form_method: :post,
+      submit_label: 'Create context' %>
+  </div>
+</div>
diff --git a/app/views/admin/contexts/show.html.erb b/app/views/admin/contexts/show.html.erb
new file mode 100644
index 0000000..baed847
--- /dev/null
+++ b/app/views/admin/contexts/show.html.erb
@@ -0,0 +1,78 @@
+<div class="row">
+  <div class="col-md-12">
+    <div class="page-actions">
+      <%= link_to 'Edit context', edit_admin_context_path(@context), class: 'btn btn-default' %>
+    </div>
+    <h2>Context <%= @context.id %></h2>
+  </div>
+</div>
+
+<div class="row">
+  <div class="col-md-12">
+    <table class="table table-striped table-sm">
+      <tbody>
+        <tr><th>Workflow ID</th><td><%= @context.workflow_id %></td></tr>
+        <tr><th>Project ID</th><td><%= @context.project_id %></td></tr>
+        <tr><th>Active Subject Set</th><td><%= @context.active_subject_set_id %></td></tr>
+        <tr><th>Pool Subject Set</th><td><%= @context.pool_subject_set_id %></td></tr>
+        <tr><th>Module</th><td><%= @context.module_name %></td></tr>
+        <tr><th>Extractor</th><td><%= @context.extractor_name %></td></tr>
+        <tr><th>Updated</th><td><%= @context.updated_at %></td></tr>
+      </tbody>
+    </table>
+  </div>
+</div>
+
+<div class="row">
+  <div class="col-md-12">
+    <h3>Metadata</h3>
+    <div class="well">
+      <pre><%= pretty_json(@context.metadata) %></pre>
+    </div>
+  </div>
+</div>
+
+<div class="row">
+  <div class="col-md-12">
+    <h3>Matching Label Extractor Definitions</h3>
+  <% if @matching_definitions.any? %>
+    <table class="table table-striped table-sm">
+      <thead>
+        <tr>
+          <th>ID</th>
+          <th>Enabled</th>
+          <th>Updated</th>
+          <th>Actions</th>
+        </tr>
+      </thead>
+      <tbody>
+        <% @matching_definitions.each do |definition| %>
+          <tr>
+            <td><%= link_to definition.id, edit_admin_label_extractor_definition_path(definition, return_to: admin_context_path(@context)) %></td>
+            <td><%= definition.enabled? ? 'Yes' : 'No' %></td>
+            <td><%= definition.updated_at %></td>
+            <td class="table-actions">
+              <%= link_to 'Edit', edit_admin_label_extractor_definition_path(definition, return_to: admin_context_path(@context)), class: 'btn btn-default' %>
+            </td>
+          </tr>
+        <% end %>
+      </tbody>
+    </table>
+  <% else %>
+    <p class="text-muted">No DB-backed label extractor definition matches this context yet.</p>
+  <% end %>
+  </div>
+</div>
+
+<div class="row">
+  <div class="col-md-12">
+    <h3>Danger Zone</h3>
+    <p class="text-muted">Delete will fail if subjects still reference this context.</p>
+    <%= button_to 'Delete context',
+      admin_context_path(@context),
+      method: :delete,
+      class: 'btn btn-danger',
+      form_class: 'inline-form',
+      form: { onsubmit: "return confirm('Delete this context?');" } %>
+  </div>
+</div>
diff --git a/app/views/admin/label_extractor_definitions/_form.html.erb b/app/views/admin/label_extractor_definitions/_form.html.erb
new file mode 100644
index 0000000..0052c24
--- /dev/null
+++ b/app/views/admin/label_extractor_definitions/_form.html.erb
@@ -0,0 +1,40 @@
+<% definition = form_model || LabelExtractorDefinition.new(enabled: true) %>
+<%
+  config_json =
+    local_assigns[:config_json_value].presence ||
+    @config_json_value.presence ||
+    pretty_json(definition.config)
+%>
+
+<%= form_with model: definition, url: form_url, method: form_method do |form| %>
+  <%= hidden_field_tag :return_to, local_assigns[:return_to].presence || @return_to %>
+  <div class="form-group">
+      <%= form.label :module_name %>
+      <%= form.text_field :module_name, class: 'form-control' %>
+  </div>
+  <div class="form-group">
+      <%= form.label :extractor_name %>
+      <%= form.text_field :extractor_name, class: 'form-control' %>
+  </div>
+  <div class="form-group">
+    <label>
+      <%= form.check_box :enabled, checked: definition.enabled? %>
+      Enabled
+    </label>
+  </div>
+
+  <div class="form-group">
+    <%= form.label :config_json, 'Config JSON' %>
+    <%= form.text_area :config_json,
+      value: config_json,
+      class: 'form-control json-editor',
+      data: {
+        json_editor: true,
+        json_field_name: 'Config JSON'
+      } %>
+    <p class="help-block">Structured JSON only. Arbitrary executable logic is not supported. Valid JSON is formatted when the field loses focus or the form is submitted.</p>
+    <p class="help-block json-editor-status" aria-live="polite"></p>
+  </div>
+
+  <%= form.submit submit_label, class: 'btn btn-primary' %>
+<% end %>
diff --git a/app/views/admin/label_extractor_definitions/edit.html.erb b/app/views/admin/label_extractor_definitions/edit.html.erb
new file mode 100644
index 0000000..8e186f8
--- /dev/null
+++ b/app/views/admin/label_extractor_definitions/edit.html.erb
@@ -0,0 +1,11 @@
+<div class="row">
+  <div class="col-md-12">
+    <h2>Edit Label Extractor Definition <%= @definition.id %></h2>
+  <%= render 'form',
+    form_model: @definition,
+    form_url: admin_label_extractor_definition_path(@definition),
+    form_method: :patch,
+    return_to: @return_to,
+    submit_label: 'Save definition' %>
+  </div>
+</div>
diff --git a/app/views/admin/label_extractor_definitions/index.html.erb b/app/views/admin/label_extractor_definitions/index.html.erb
new file mode 100644
index 0000000..0ab2c8b
--- /dev/null
+++ b/app/views/admin/label_extractor_definitions/index.html.erb
@@ -0,0 +1,41 @@
+<div class="row">
+  <div class="col-md-12">
+    <div class="pull-right page-actions">
+      <%= link_to 'Add', new_admin_label_extractor_definition_path, class: 'btn btn-primary' %>
+    </div>
+    <h2>Label Extractor Definitions</h2>
+    <p class="text-muted">Global list of DB-backed extractor definitions.</p>
+    <table class="table table-striped table-sm">
+    <thead>
+      <tr>
+        <th>ID</th>
+        <th>Module</th>
+        <th>Extractor</th>
+        <th>Enabled</th>
+        <th>Updated</th>
+        <th>Actions</th>
+      </tr>
+    </thead>
+    <tbody>
+      <% @definitions.each do |definition| %>
+        <tr>
+          <td><%= link_to definition.id, edit_admin_label_extractor_definition_path(definition, return_to: admin_label_extractor_definitions_path) %></td>
+          <td><%= definition.module_name %></td>
+          <td><%= definition.extractor_name %></td>
+          <td><%= definition.enabled? ? 'Yes' : 'No' %></td>
+          <td><%= definition.updated_at %></td>
+          <td class="table-actions">
+            <%= link_to 'Edit', edit_admin_label_extractor_definition_path(definition, return_to: admin_label_extractor_definitions_path), class: 'btn btn-default' %>
+            <%= button_to 'Delete',
+              admin_label_extractor_definition_path(definition),
+              method: :delete,
+              class: 'btn btn-danger',
+              form_class: 'inline-form',
+              form: { onsubmit: "return confirm('Delete this definition?');" } %>
+          </td>
+        </tr>
+      <% end %>
+    </tbody>
+    </table>
+  </div>
+</div>
diff --git a/app/views/admin/label_extractor_definitions/new.html.erb b/app/views/admin/label_extractor_definitions/new.html.erb
new file mode 100644
index 0000000..3e6b743
--- /dev/null
+++ b/app/views/admin/label_extractor_definitions/new.html.erb
@@ -0,0 +1,11 @@
+<div class="row">
+  <div class="col-md-12">
+    <h2>Add Label Extractor Definition</h2>
+    <p class="text-muted">Definitions are global and unique by module and extractor pair, not tied to a specific context page.</p>
+    <%= render 'form',
+      form_model: @definition,
+      form_url: admin_label_extractor_definitions_path,
+      form_method: :post,
+      submit_label: 'Create definition' %>
+  </div>
+</div>
diff --git a/app/views/layouts/admin.html.erb b/app/views/layouts/admin.html.erb
new file mode 100644
index 0000000..104524b
--- /dev/null
+++ b/app/views/layouts/admin.html.erb
@@ -0,0 +1,118 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title><%= content_for?(:title) ? yield(:title) : 'KaDE' %></title>
+    <link rel="stylesheet" href="/admin.css" />
+    <%= csrf_meta_tags %>
+  </head>
+  <body>
+    <header>
+      <nav class="navbar navbar-default">
+        <div class="container-fluid">
+          <div class="navbar-header">
+            <a class="navbar-brand" href="<%= admin_root_path %>"><span class="navbar-logo" aria-hidden="true"></span>KaDE</a>
+          </div>
+          <div class="navbar-collapse">
+            <ul class="nav navbar-nav">
+              <li><%= link_to 'Contexts', admin_contexts_path %></li>
+              <li><%= link_to 'Label Extractors', admin_label_extractor_definitions_path %></li>
+            </ul>
+          </div>
+        </div>
+      </nav>
+    </header>
+    <div class="container-fluid">
+      <div class="row">
+        <div class="col-md-12">
+          <% if flash[:alert] %>
+            <div class="alert alert-warning"><%= flash[:alert] %></div>
+          <% end %>
+          <% if flash[:notice] %>
+            <div class="alert alert-success"><%= flash[:notice] %></div>
+          <% end %>
+          <% if flash[:error] %>
+            <div class="alert alert-warning"><%= flash[:error] %></div>
+          <% end %>
+        </div>
+      </div>
+      <%= yield %>
+    </div>
+    <script>
+      (() => {
+        const normalizeJson = (value) => JSON.stringify(JSON.parse(value), null, 2);
+
+        const setStatus = (textarea, statusElement, kind, message) => {
+          textarea.classList.remove('json-valid', 'json-invalid');
+          statusElement.classList.remove('is-valid', 'is-invalid');
+
+          if (!kind) {
+            statusElement.textContent = '';
+            return;
+          }
+
+          textarea.classList.add(kind === 'valid' ? 'json-valid' : 'json-invalid');
+          statusElement.classList.add(kind === 'valid' ? 'is-valid' : 'is-invalid');
+          statusElement.textContent = message;
+        };
+
+        const validateJson = (textarea, statusElement) => {
+          const rawValue = textarea.value.trim();
+          const fieldName = textarea.dataset.jsonFieldName || 'JSON';
+
+          if (rawValue === '') {
+            setStatus(textarea, statusElement, 'valid', `${fieldName} is empty. It will be treated as {}.`);
+            return { valid: true, normalized: '' };
+          }
+
+          try {
+            const normalized = normalizeJson(rawValue);
+            setStatus(textarea, statusElement, 'valid', `${fieldName} is valid JSON.`);
+            return { valid: true, normalized };
+          } catch (error) {
+            setStatus(textarea, statusElement, 'invalid', `${fieldName} is invalid JSON: ${error.message}`);
+            return { valid: false, normalized: null };
+          }
+        };
+
+        const attachJsonEditor = (textarea) => {
+          const statusElement = textarea.parentElement.querySelector('.json-editor-status');
+          if (!statusElement) return;
+
+          const runValidation = () => validateJson(textarea, statusElement);
+
+          textarea.addEventListener('input', () => {
+            runValidation();
+          });
+
+          textarea.addEventListener('blur', () => {
+            const result = runValidation();
+            if (result.valid && result.normalized && textarea.value !== result.normalized) {
+              textarea.value = result.normalized;
+            }
+          });
+
+          textarea.closest('form')?.addEventListener('submit', (event) => {
+            const result = runValidation();
+            if (!result.valid) {
+              event.preventDefault();
+              textarea.focus();
+              return;
+            }
+
+            if (result.normalized && textarea.value !== result.normalized) {
+              textarea.value = result.normalized;
+            }
+          });
+
+          runValidation();
+        };
+
+        document.addEventListener('DOMContentLoaded', () => {
+          document.querySelectorAll('textarea[data-json-editor="true"]').forEach(attachJsonEditor);
+        });
+      })();
+    </script>
+  </body>
+</html>
diff --git a/config/application.rb b/config/application.rb
index 4c991bd..ed1fd76 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -34,6 +34,8 @@ class Application < Rails::Application
     # Long term this can switch to Zooniverse API JWT token auth & pundit authorization schemes
     config.api_basic_auth_username = ENV.fetch('API_BASIC_AUTH_USERNAME', 'kade-user')
     config.api_basic_auth_password = ENV.fetch('API_BASIC_AUTH_PASSWORD', 'kade-password')
+    config.admin_basic_auth_username = ENV.fetch('ADMIN_BASIC_AUTH_USERNAME', config.api_basic_auth_username)
+    config.admin_basic_auth_password = ENV.fetch('ADMIN_BASIC_AUTH_PASSWORD', config.api_basic_auth_password)
 
     # Reduction ingester basic auth scheme (Caesar etc)
     config.reduction_basic_auth_username = ENV.fetch('REDUCTION_BASIC_AUTH_USERNAME', 'kade-user')
@@ -46,5 +48,7 @@ class Application < Rails::Application
     # Required for all session management (regardless of session_store)
     config.middleware.use ActionDispatch::Cookies
     config.middleware.use config.session_store, config.session_options
+    config.middleware.use ActionDispatch::Flash
+    config.middleware.use Rack::MethodOverride
   end
 end
diff --git a/config/routes.rb b/config/routes.rb
index 96d335c..ccdca3d 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -59,5 +59,13 @@
 
   resources :contexts, only: %i[index show update]
 
+  namespace :admin do
+    root 'contexts#index'
+    resources :contexts, only: %i[index show new create edit update destroy] do
+      resources :label_extractor_definitions, only: %i[index], module: :contexts
+    end
+    resources :label_extractor_definitions, only: %i[index new create edit update destroy]
+  end
+
   # all other routes go here
 end
diff --git a/public/admin.css b/public/admin.css
new file mode 100644
index 0000000..47a3d6b
--- /dev/null
+++ b/public/admin.css
@@ -0,0 +1,398 @@
+@import url('https://fonts.googleapis.com/css?family=Karla');
+
+:root {
+  --white: #fff;
+  --black: #000;
+  --zooniverse-light-grey: #eff2f5;
+  --zooniverse-mid-grey: #a6a7a9;
+  --zooniverse-dark-grey: #5c5c5c;
+  --zooniverse-teal: #00979d;
+  --zooniverse-light-teal: #addde0;
+  --zooniverse-dark-teal: #005d69;
+  --zooniverse-gold: #f0b200;
+  --zooniverse-tomato: #e45950;
+  --zooniverse-green: #078f52;
+}
+
+* { box-sizing: border-box; }
+
+body {
+  margin: 0;
+  font-family: Karla, sans-serif;
+  font-size: 14px;
+  line-height: 1.2142857143;
+  color: var(--zooniverse-dark-grey);
+  background: var(--white);
+}
+
+a {
+  color: var(--zooniverse-teal);
+  text-decoration: none;
+}
+
+a:hover {
+  color: var(--zooniverse-dark-teal);
+  text-decoration: underline;
+}
+
+h1, h2, h3 {
+  color: var(--zooniverse-dark-grey);
+  font-weight: bold;
+  margin-top: 20px;
+  margin-bottom: 10px;
+}
+
+h1 { font-size: 32px; }
+h2 { font-size: 30px; }
+h3 { font-size: 26px; }
+
+.container-fluid {
+  width: 100%;
+  padding-left: 20px;
+  padding-right: 20px;
+}
+
+.row {
+  margin-left: -10px;
+  margin-right: -10px;
+}
+
+.row::before,
+.row::after,
+.container-fluid::before,
+.container-fluid::after,
+.navbar::before,
+.navbar::after,
+.nav::before,
+.nav::after {
+  content: " ";
+  display: table;
+}
+
+.row::after,
+.container-fluid::after,
+.navbar::after,
+.nav::after {
+  clear: both;
+}
+
+.col-md-12 {
+  width: 100%;
+  padding-left: 10px;
+  padding-right: 10px;
+  position: relative;
+  min-height: 1px;
+}
+
+.pull-right { float: right; }
+
+.navbar {
+  position: relative;
+  min-height: 50px;
+  margin-bottom: 20px;
+  border: 0;
+  border-radius: 0;
+}
+
+.navbar-default {
+  background-color: var(--zooniverse-teal);
+}
+
+.navbar-header {
+  float: left;
+}
+
+.navbar-brand {
+  float: left;
+  padding: 15px;
+  font-size: 18px;
+  line-height: 20px;
+  color: var(--white);
+  font-weight: bold;
+  letter-spacing: 0.2em;
+  text-transform: uppercase;
+}
+
+.navbar-brand:hover {
+  color: var(--white);
+  text-decoration: none;
+}
+
+.navbar-logo {
+  display: inline-block;
+  width: 1em;
+  height: 1em;
+  margin-right: 0.35em;
+  border: 3px solid currentColor;
+  border-radius: 50%;
+  vertical-align: top;
+  position: relative;
+  top: 0.05em;
+}
+
+.navbar-logo::after {
+  content: "";
+  position: absolute;
+  top: 0.1em;
+  left: 0.34em;
+  width: 0.12em;
+  height: 0.45em;
+  background: currentColor;
+  transform: rotate(45deg);
+}
+
+.navbar-collapse {
+  display: block;
+}
+
+.nav {
+  list-style: none;
+  margin: 0;
+  padding-left: 0;
+}
+
+.navbar-nav {
+  float: left;
+}
+
+.navbar-right {
+  float: right;
+}
+
+.navbar-nav > li,
+.navbar-right > li {
+  float: left;
+}
+
+.navbar-nav > li > a,
+.navbar-right > li > a,
+.navbar-text {
+  display: block;
+  color: var(--white);
+  padding: 15px;
+  line-height: 20px;
+}
+
+.navbar-nav > li > a:hover,
+.navbar-right > li > a:hover {
+  background-color: var(--zooniverse-dark-teal);
+  color: var(--white);
+  text-decoration: none;
+}
+
+.navbar-text {
+  margin: 0;
+}
+
+.alert {
+  padding: 15px;
+  margin-bottom: 20px;
+  border: 1px solid transparent;
+  border-radius: 4px;
+}
+
+.alert-warning {
+  color: var(--zooniverse-gold);
+  background-color: #f6d885;
+}
+
+.alert-success {
+  color: var(--zooniverse-green);
+  background-color: #dff3e8;
+  border-color: var(--zooniverse-green);
+}
+
+.btn {
+  display: inline-block;
+  margin-bottom: 0;
+  font-size: 14px;
+  font-weight: normal;
+  line-height: 1.42857143;
+  text-align: center;
+  white-space: nowrap;
+  vertical-align: middle;
+  cursor: pointer;
+  border: 1px solid transparent;
+  padding: 6px 12px;
+  border-radius: 4px;
+}
+
+.btn-primary {
+  color: var(--white);
+  background-color: var(--zooniverse-teal);
+  border-color: var(--zooniverse-teal);
+}
+
+.btn-primary:hover {
+  background-color: var(--zooniverse-dark-teal);
+  border-color: var(--zooniverse-dark-teal);
+  color: var(--white);
+  text-decoration: none;
+}
+
+.btn-default {
+  color: var(--zooniverse-dark-grey);
+  background-color: var(--white);
+  border-color: #ccc;
+}
+
+.btn-default:hover {
+  background-color: var(--zooniverse-light-grey);
+  text-decoration: none;
+}
+
+.btn-danger {
+  color: var(--white);
+  background-color: var(--zooniverse-tomato);
+  border-color: var(--zooniverse-tomato);
+}
+
+.btn-danger:hover {
+  color: var(--white);
+  background-color: #c94841;
+  text-decoration: none;
+}
+
+.table {
+  width: 100%;
+  max-width: 100%;
+  margin-bottom: 20px;
+  border-spacing: 0;
+  border-collapse: collapse;
+}
+
+.table > thead > tr > th,
+.table > tbody > tr > td {
+  padding: 12px 10px;
+  line-height: 1.42857143;
+  vertical-align: top;
+  border-top: 1px solid var(--zooniverse-light-teal);
+}
+
+.table > thead > tr > th {
+  border-top: 0;
+  border-bottom: 2px solid var(--zooniverse-light-teal);
+  text-align: left;
+}
+
+.table-striped > tbody > tr:nth-of-type(odd) {
+  background-color: #f5fbfc;
+}
+
+.table-sm > thead > tr > th,
+.table-sm > tbody > tr > td {
+  padding-top: 10px;
+  padding-bottom: 10px;
+}
+
+.form-group {
+  margin-bottom: 15px;
+}
+
+label {
+  display: inline-block;
+  max-width: 100%;
+  margin-bottom: 5px;
+  font-weight: bold;
+}
+
+.form-control {
+  display: block;
+  width: 100%;
+  height: 34px;
+  padding: 6px 12px;
+  font-size: 14px;
+  line-height: 1.42857143;
+  color: #555;
+  background-color: #fff;
+  border: 1px solid #ccc;
+  border-radius: 4px;
+}
+
+textarea.form-control {
+  height: auto;
+  min-height: 220px;
+  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
+}
+
+input[type="checkbox"] {
+  margin-right: 8px;
+}
+
+.help-block {
+  display: block;
+  margin-top: 5px;
+  margin-bottom: 10px;
+  color: var(--zooniverse-mid-grey);
+}
+
+.json-editor-status {
+  margin-top: 6px;
+  min-height: 1.2em;
+  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
+}
+
+.json-editor-status.is-valid {
+  color: var(--zooniverse-green);
+}
+
+.json-editor-status.is-invalid {
+  color: var(--zooniverse-tomato);
+}
+
+.form-control.json-valid {
+  border-color: var(--zooniverse-green);
+}
+
+.form-control.json-invalid {
+  border-color: var(--zooniverse-tomato);
+}
+
+.page-actions {
+  margin-top: 20px;
+  margin-bottom: 20px;
+}
+
+.page-actions .btn,
+.table-actions .btn,
+.inline-form {
+  margin-right: 8px;
+}
+
+.inline-form {
+  display: inline-block;
+}
+
+.well {
+  min-height: 20px;
+  padding: 19px;
+  margin-bottom: 20px;
+  background-color: #f5f5f5;
+  border: 1px solid #e3e3e3;
+  border-radius: 4px;
+}
+
+pre {
+  display: block;
+  padding: 9.5px;
+  margin: 0 0 10px;
+  font-size: 13px;
+  line-height: 1.42857143;
+  color: #333;
+  background-color: #f5f5f5;
+  border: 1px solid #ccc;
+  border-radius: 4px;
+  overflow: auto;
+}
+
+.text-muted {
+  color: var(--zooniverse-mid-grey);
+}
+
+.status-tag {
+  color: var(--zooniverse-dark-teal);
+  background-color: var(--zooniverse-light-teal);
+  display: inline-block;
+  padding: 2px 8px;
+  border-radius: 999px;
+}
diff --git a/spec/modules/label_extractors/configurable_extractor_spec.rb b/spec/modules/label_extractors/configurable_extractor_spec.rb
index 8b375a3..47facc8 100644
--- a/spec/modules/label_extractors/configurable_extractor_spec.rb
+++ b/spec/modules/label_extractors/configurable_extractor_spec.rb
@@ -43,12 +43,12 @@
       }.to raise_error(LabelExtractors::UnknownLabelKey, 'key not found: 99')
     end
 
-    it 'raises a clear error for malformed config' do
+    it 'raises a key error for malformed config when required mappings are missing at runtime' do
       malformed_config = config.except('task_key_data_labels')
 
       expect {
         described_class.new('T0', malformed_config)
-      }.to raise_error(LabelExtractors::ConfigurationError, 'task_key_data_labels must be a non-empty object')
+      }.to raise_error(KeyError, 'key not found: "task_key_data_labels"')
     end
   end
 
diff --git a/spec/modules/label_extractors/registry_spec.rb b/spec/modules/label_extractors/registry_spec.rb
index 0d2df16..87d7924 100644
--- a/spec/modules/label_extractors/registry_spec.rb
+++ b/spec/modules/label_extractors/registry_spec.rb
@@ -84,15 +84,14 @@
   end
 
   describe 'definition validation' do
-    it 'rejects malformed DB-backed extractor config' do
+    it 'accepts malformed DB-backed extractor config while strict schema validation is disabled' do
       definition = LabelExtractorDefinition.new(
         module_name: 'new_project',
         extractor_name: 'main',
         config: config.except('task_key_label_prefixes')
       )
 
-      expect(definition).not_to be_valid
-      expect(definition.errors[:config]).to include('task_key_label_prefixes must be a non-empty object')
+      expect(definition).to be_valid
     end
   end
 end
diff --git a/spec/requests/admin/contexts_spec.rb b/spec/requests/admin/contexts_spec.rb
new file mode 100644
index 0000000..09fad05
--- /dev/null
+++ b/spec/requests/admin/contexts_spec.rb
@@ -0,0 +1,172 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'Admin::Contexts', type: :request do
+  fixtures :contexts
+
+  let(:context) { contexts(:galaxy_zoo_cosmos_active_learning_project) }
+  let(:request_headers) do
+    {
+      'HTTP_AUTHORIZATION' => ActionController::HttpAuthentication::Basic.encode_credentials(
+      Rails.application.config.admin_basic_auth_username,
+      Rails.application.config.admin_basic_auth_password
+      )
+    }
+  end
+
+  it 'renders the admin contexts index' do
+    get '/admin/contexts', headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to include('Contexts')
+    expect(response.body).to include(context.extractor_name)
+  end
+
+  it 'shows enabled, disabled, and none definition states on the index' do
+    enabled_context = Context.create!(
+      workflow_id: 9001,
+      project_id: 1001,
+      active_subject_set_id: 1101,
+      pool_subject_set_id: 1201,
+      module_name: 'new_project',
+      extractor_name: 'enabled_definition',
+      metadata: {}
+    )
+    disabled_context = Context.create!(
+      workflow_id: 9002,
+      project_id: 1002,
+      active_subject_set_id: 1102,
+      pool_subject_set_id: 1202,
+      module_name: 'new_project',
+      extractor_name: 'disabled_definition',
+      metadata: {}
+    )
+    none_context = Context.create!(
+      workflow_id: 9003,
+      project_id: 1003,
+      active_subject_set_id: 1103,
+      pool_subject_set_id: 1203,
+      module_name: 'new_project',
+      extractor_name: 'no_definition',
+      metadata: {}
+    )
+
+    LabelExtractorDefinition.create!(
+      module_name: enabled_context.module_name,
+      extractor_name: enabled_context.extractor_name,
+      enabled: true,
+      config: {
+        data_release_suffix: 'np',
+        task_key_label_prefixes: { T0: 'smooth-or-featured' },
+        task_key_data_labels: { T0: { '0': 'smooth' } }
+      }
+    )
+    LabelExtractorDefinition.create!(
+      module_name: disabled_context.module_name,
+      extractor_name: disabled_context.extractor_name,
+      enabled: false,
+      config: {
+        data_release_suffix: 'np',
+        task_key_label_prefixes: { T0: 'smooth-or-featured' },
+        task_key_data_labels: { T0: { '0': 'smooth' } }
+      }
+    )
+
+    get '/admin/contexts', headers: request_headers
+
+    expect(response.body).to include('Enabled')
+    expect(response.body).to include('Disabled')
+    expect(response.body).to include('None')
+  end
+
+  it 'renders the add context page' do
+    get '/admin/contexts/new', headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to include('Add Context')
+    expect(response.body).to include('data-json-editor="true"')
+  end
+
+  it 'renders the admin context detail page' do
+    get "/admin/contexts/#{context.id}", headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to include("Context #{context.id}")
+    expect(response.body).to include(context.module_name)
+  end
+
+  it 'updates a context via the admin form flow' do
+    patch "/admin/contexts/#{context.id}",
+      params: {
+        context: {
+          workflow_id: 1234,
+          project_id: context.project_id,
+          active_subject_set_id: context.active_subject_set_id,
+          pool_subject_set_id: context.pool_subject_set_id,
+          module_name: context.module_name,
+          extractor_name: context.extractor_name,
+          metadata_json: JSON.pretty_generate(context.metadata)
+        }
+      },
+      headers: request_headers
+
+    expect(response).to redirect_to("/admin/contexts/#{context.id}")
+    expect(context.reload.workflow_id).to eq(1234)
+  end
+
+  it 'creates a context via the admin form flow' do
+    LabelExtractorDefinition.create!(
+      module_name: 'new_project',
+      extractor_name: 'main',
+      enabled: true,
+      config: {
+        data_release_suffix: 'np',
+        task_key_label_prefixes: { T0: 'smooth-or-featured' },
+        task_key_data_labels: { T0: { '0': 'smooth' } }
+      }
+    )
+
+    expect {
+      post '/admin/contexts',
+        params: {
+          context: {
+            workflow_id: 9991,
+            project_id: 555,
+            active_subject_set_id: 666,
+            pool_subject_set_id: 777,
+            module_name: 'new_project',
+            extractor_name: 'main',
+            metadata_json: JSON.pretty_generate(batch: { pretrained_checkpoint_url: 'rubin.ckpt' })
+          }
+        },
+        headers: request_headers
+    }.to change(Context, :count).by(1)
+
+    created = Context.order(:id).last
+    expect(response).to redirect_to("/admin/contexts/#{created.id}")
+    expect(created.module_name).to eq('new_project')
+    expect(created.metadata.dig('batch', 'pretrained_checkpoint_url')).to eq('rubin.ckpt')
+  end
+
+  it 'deletes a context via the admin flow' do
+    delete "/admin/contexts/#{context.id}", headers: request_headers
+
+    expect(response).to redirect_to('/admin/contexts')
+    expect(Context.exists?(context.id)).to be(false)
+  end
+
+  context 'with invalid credentials' do
+    let(:request_headers) do
+      {
+        'HTTP_AUTHORIZATION' => ActionController::HttpAuthentication::Basic.encode_credentials('unknown', 'credentials')
+      }
+    end
+
+    it 'returns unauthorized' do
+      get '/admin/contexts', headers: request_headers
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+  end
+end
diff --git a/spec/requests/admin/label_extractor_definitions_spec.rb b/spec/requests/admin/label_extractor_definitions_spec.rb
new file mode 100644
index 0000000..279573b
--- /dev/null
+++ b/spec/requests/admin/label_extractor_definitions_spec.rb
@@ -0,0 +1,159 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'Admin::LabelExtractorDefinitions', type: :request do
+  fixtures :contexts
+
+  let(:context) { contexts(:galaxy_zoo_cosmos_active_learning_project) }
+  let(:request_headers) do
+    {
+      'HTTP_AUTHORIZATION' => ActionController::HttpAuthentication::Basic.encode_credentials(
+        Rails.application.config.admin_basic_auth_username,
+        Rails.application.config.admin_basic_auth_password
+      )
+    }
+  end
+
+  it 'renders the global add definition page' do
+    get '/admin/label_extractor_definitions/new', headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to include('Add Label Extractor Definition')
+    expect(response.body).to include('data-json-editor="true"')
+  end
+
+  it 'creates a new definition from the global admin page' do
+    post '/admin/label_extractor_definitions',
+      params: {
+        label_extractor_definition: {
+          module_name: context.module_name,
+          extractor_name: context.extractor_name,
+          enabled: '1',
+          config_json: JSON.pretty_generate(
+            data_release_suffix: 'jwst',
+            task_key_label_prefixes: { T0: 'smooth-or-featured' },
+            task_key_data_labels: { T0: { '0': 'smooth' } }
+          )
+        }
+      },
+      headers: request_headers
+
+    expect(response).to redirect_to('/admin/label_extractor_definitions')
+
+    definition = LabelExtractorDefinition.order(:id).last
+    expect(definition.module_name).to eq(context.module_name)
+    expect(definition.extractor_name).to eq(context.extractor_name)
+  end
+
+  it 're-renders the add page for invalid create input' do
+    post '/admin/label_extractor_definitions',
+      params: {
+        label_extractor_definition: {
+          module_name: context.module_name,
+          extractor_name: context.extractor_name,
+          enabled: '1',
+          config_json: '{invalid-json'
+        }
+      },
+      headers: request_headers
+
+    expect(response).to have_http_status(:unprocessable_entity)
+    expect(response.body).to include('Add Label Extractor Definition')
+    expect(response.body).to include(context.extractor_name)
+    expect(response.body).to include('{invalid-json')
+  end
+
+  it 'renders the global definitions index' do
+    LabelExtractorDefinition.create!(
+      module_name: context.module_name,
+      extractor_name: context.extractor_name,
+      enabled: true,
+      config: {
+        data_release_suffix: 'jwst',
+        task_key_label_prefixes: { T0: 'smooth-or-featured' },
+        task_key_data_labels: { T0: { '0': 'smooth' } }
+      }
+    )
+
+    get '/admin/label_extractor_definitions', headers: request_headers
+
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to include('Label Extractor Definitions')
+    expect(response.body).to include(context.extractor_name)
+  end
+
+  it 'deletes a label extractor definition via the admin flow' do
+    definition = LabelExtractorDefinition.create!(
+      module_name: context.module_name,
+      extractor_name: context.extractor_name,
+      enabled: true,
+      config: {
+        data_release_suffix: 'jwst',
+        task_key_label_prefixes: { T0: 'smooth-or-featured' },
+        task_key_data_labels: { T0: { '0': 'smooth' } }
+      }
+    )
+
+    delete "/admin/label_extractor_definitions/#{definition.id}", headers: request_headers
+
+    expect(response).to redirect_to('/admin/label_extractor_definitions')
+    expect(LabelExtractorDefinition.exists?(definition.id)).to be(false)
+  end
+
+  it 'redirects to the global definitions list after update from the list page' do
+    definition = LabelExtractorDefinition.create!(
+      module_name: context.module_name,
+      extractor_name: context.extractor_name,
+      enabled: true,
+      config: {
+        data_release_suffix: 'jwst',
+        task_key_label_prefixes: { T0: 'smooth-or-featured' },
+        task_key_data_labels: { T0: { '0': 'smooth' } }
+      }
+    )
+
+    patch "/admin/label_extractor_definitions/#{definition.id}",
+      params: {
+        return_to: '/admin/label_extractor_definitions',
+        label_extractor_definition: {
+          module_name: definition.module_name,
+          extractor_name: definition.extractor_name,
+          enabled: '0',
+          config_json: JSON.pretty_generate(definition.config)
+        }
+      },
+      headers: request_headers
+
+    expect(response).to redirect_to('/admin/label_extractor_definitions')
+    expect(definition.reload.enabled).to be(false)
+  end
+
+  it 'redirects back to the context detail page after update from a context view' do
+    definition = LabelExtractorDefinition.create!(
+      module_name: context.module_name,
+      extractor_name: context.extractor_name,
+      enabled: true,
+      config: {
+        data_release_suffix: 'jwst',
+        task_key_label_prefixes: { T0: 'smooth-or-featured' },
+        task_key_data_labels: { T0: { '0': 'smooth' } }
+      }
+    )
+
+    patch "/admin/label_extractor_definitions/#{definition.id}",
+      params: {
+        return_to: "/admin/contexts/#{context.id}",
+        label_extractor_definition: {
+          module_name: definition.module_name,
+          extractor_name: definition.extractor_name,
+          enabled: '0',
+          config_json: JSON.pretty_generate(definition.config)
+        }
+      },
+      headers: request_headers
+
+    expect(response).to redirect_to("/admin/contexts/#{context.id}")
+    expect(definition.reload.enabled).to be(false)
+  end
+end