[Ability] update-post-content — Read, modify, and save post content with validated block markup #34

Use Case

User says "add a paragraph after the heading" or "delete the second block" in the block editor chat. AI reads the current post blocks, performs the requested insert/replace/delete operation, validates the markup with parse_blocks(), and saves via REST API. Destructive operations (replace, delete) require confirmation.

Checklist

• Writer: Define natural language triggers, expected response format, and confirmation requirements per operation type
• PHP Dev: Create includes/abilities/update-post-content.php using register_agentic_ability()
• JS Dev: Create src/extensions/abilities/update-post-content.js with registerAbility()
• JS Dev: Register in src/extensions/abilities/index.js
• LLM Tester: Add test cases to tests/abilities/core-abilities.test.js
• Build & verify: npm run build and npm run test:abilities

References

• Abilities Guide
• Existing destructive ability example: includes/abilities/plugin-deactivate.php + src/extensions/abilities/plugin-deactivate.js

Notes

Operations: insert, replace, delete blocks by position. Reads current content from editor state or REST API (GET /wp/v2/posts/{id}). Saves via PUT /wp/v2/posts/{id} with content field. Validates all markup with parse_blocks() before saving — zero "Attempt Block Recovery" errors. Replace and delete operations are destructive and need requiresConfirmation: true. Depends on Goal 7 (block editor chat window) for the editor-side surface. See CLOUDFEST_HACKATHON.md Goal 8.