Rendering with layouts

[johnpaulashenfelter]

I may be doing something wrong, but I'm trying to add a layout so I can standardize some metadata in the JSON output.

I've got an layouts\api.jb file and I've requested that layout in the controller generating the json output.

ArgumentError in Api::PostsController#show
unknown keywords: id, title, slug, blurb, classification, higher_ed, sponsor_label, comment_count, share_count, tags, authors, image, date, content, description, schema, meta, chartbeat

Extracted source (around line #172):
    def initialize(*)
      @html_safe = true
      super
    end

    def initialize_copy(other)
....
.bundle/gems/activesupport-4.2.7.1/lib/active_support/core_ext/string/output_safety.rb:172:in `initialize'
.bundle/gems/activesupport-4.2.7.1/lib/active_support/core_ext/string/output_safety.rb:172:in `initialize'
.bundle/gems/actionview-4.2.7.1/lib/action_view/flows.rb:18:in `new'
.bundle/gems/actionview-4.2.7.1/lib/action_view/flows.rb:18:in `set'
.bundle/gems/actionview-4.2.7.1/lib/action_view/renderer/template_renderer.rb:65:in `render_with_layout'
.bundle/gems/skylight-0.10.6/lib/skylight/probes/action_view.rb:32:in `block in render_with_layout'
.bundle/gems/actionview-4.2.7.1/lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
.bundle/gems/activesupport-4.2.7.1/lib/active_support/notifications.rb:164:in `block in instrument'
.bundle/gems/activesupport-4.2.7.1/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
.bundle/gems/activesupport-4.2.7.1/lib/active_support/notifications.rb:164:in `instrument'
.bundle/gems/actionview-4.2.7.1/lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
.bundle/gems/skylight-0.10.6/lib/skylight/probes/action_view.rb:31:in `render_with_layout'
.bundle/gems/actionview-4.2.7.1/lib/action_view/renderer/template_renderer.rb:52:in `render_template'

I've tried ERB layout template, using content_for, assigning the template output to variables (including instance vars) and using yield or ERB rendering. All lead to similar issues.

Am I totally missing something simple @amatsuda ?