Update subcontext feature to specify required vs conditional selection
>>> [!note] Migrated issue
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Reported by: [kristen pol](https://www.drupal.org/user/8389)
Related to !64
>>>
<p>[Tracker]<br>
<strong>Update Summary: </strong>[One-line status update for stakeholders]<br>
<strong>Check-in Date: </strong>MM/DD/YYYY<br>
<strong>Blocked by: </strong>[#XXXXXX] (New issues on new lines)<br>
<strong>Additional Collaborators: </strong> @username1, @username2<br>
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[/Tracker]</p>
<h3 id="summary-problem-motivation">Problem/Motivation</h3>
<p>Follow-up to:</p>
<p><span class="drupalorg-gitlab-issue-link project-issue-status-info project-issue-status-7"><a href="https://www.drupal.org/project/ai_context/issues/3569312" title="Status: Closed (fixed)">#3569312: Add parent / child relationship for context</a></span><br>
<span class="drupalorg-gitlab-issue-link project-issue-status-info project-issue-status-7"><a href="https://www.drupal.org/project/ai_context/issues/3569313" title="Status: Closed (fixed)">#3569313: Create design for context list UI to include subcontext</a></span></p>
<p>Subcontext has been introduced, but we need to take it a step further to make it useful.</p>
<p>We need to let the user specify whether the subcontext is required by default or conditionally selected.</p>
<h3 id="summary-proposed-resolution">Proposed resolution</h3>
<p>Discuss UX and update the context add/edit form</p>
<h3 id="summary-remaining-tasks">Target date or deadline</h3>
<p>February 2026</p>
<h3 id="summary-remaining-tasks">Remaining tasks</h3>
<ul>
<li>Discuss UX</li>
<li>Mockup approach</li>
<li>Implement</li>
<li>Review and test</li>
</ul>
<h3 id="testing-notes">Testing notes</h3>
<ol>
<li>Install Drupal 11.3</li>
<li>Install ai 1.3, ai_agents, ai_agents_debugger</li>
<li>Install ai_context dev (and switch to this MR branch)</li>
<li>Add context item (fill in fields and save): /admin/ai/context/items/add</li>
<li>Note: you should not see the parent or subcontext type on the form</li>
<li>Choose "Add subcontext" under operations for the new context item on /admin/ai/context/items</li>
<li>Note: you should see the parent and subcontext type on the form</li>
<li>Fill in the fields and save the subcontext</li>
<li>The subcontext will be nested under the parent context on /admin/ai/context/items</li>
<li>Go to agent settings for taxonomy agent: /admin/ai/context/settings/agents/taxonomy_agent_config/edit</li>
<li>Choose "Always include" for parent item and leave subcontext to "Subcontext inclusion"</li>
<li>Go to agent debugger: /admin/config/ai/agents/debug?agent_id=taxonomy_agent_config</li>
<li>Prompt: "list vocabularies" and choose model and click "Run Agent"</li>
<li>Look at <code>AI INPUT</code> on right</li>
<li>You should see the subcontext added along with its parent</li>
<li>Note: The rest of the selection logic (conditional vs required) will be done in a separate issue as the selection rules need to be reworked in general</li>
</ol>
<h3 id="summary-ai-usage">AI usage (if applicable)</h3>
<p>[ ] AI Assisted Issue<br>
This issue was generated with AI assistance, but was reviewed and refined by the creator.</p>
<p>[ ] AI Assisted Code<br>
This code was mainly generated by a human, with AI autocompleting or parts AI generated, but under full human supervision.</p>
<p>[x] AI Generated Code<br>
This code was mainly generated by an AI with human guidance, and reviewed, tested, and refined by a human.</p>
<p>[ ] Vibe Coded<br>
This code was generated by an AI and has only been functionally tested.</p>
> Related issue: [Issue #3569311](https://www.drupal.org/node/3569311)
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