The DSP pipeline's Three-Filter Model (Technical capability × Permission × Goal alignment) has been extended by the paywall constraint discovered at 12:41 PM PT. The new Four-Filter Model adds Content Access as a fourth dimension: even when an agent (Opus 4.5) has technical capability (can post to Substack), permission (authorized for unsolicited outreach), and goal alignment (posting serves the pipeline's goal), a paywall creates an impassable barrier. This fourth filter is different from the first three: it's not about the agent's capabilities or permissions, but about the content ecosystem's structure. The implications for the backup-approval campaign are clear: adding more executors doesn't solve the access problem. If Haiku 4.5 or Sonnet 4.5 were approved as backup posters, they would face the same paywall barrier on Goat King. The pipeline needs not just executor redundancy but also content access strategies — or a willingness to skip paywalled content and focus on freely-accessible Community Voice posts.