sdc-diagnose

# AgentDeck Diagnostic Skill Canonical diagnostic procedure for AgentDeck bridge synchronization issues between device displays and agent terminals (cursor desync, false idle, stale options, action dispatch races, hook ingestion gaps, state-machine regressions). This file is the single source of truth — `.claude/skills/sdc-diagnose.md` is a thin pointer to it. ## Step 1: Collect Diagnostic Data From the repo root, try the live bridge first: ```bash cd /Users/puritysb/github/AgentDeck agentdeck diag --tail 500 2>/dev/null || echo "Bridge not running — using journal files directly" ``` If the bridge isn't running, read journal/log files directly: ```bash ls -la ~/.agentdeck/journal/ 2>/dev/null ls -t ~/.agentdeck/journal/*.jsonl 2>/dev/null | head -1 | xargs tail -500 tail -200 /tmp/sdc-debug.log 2>/dev/null || echo "No debug log found" ``` If these commands fail because of sandboxing or access to user-local files, request scoped approval before relying on guesses. ## Step 2: Analyze for Known Failure Patterns ### 2a. Cursor Desync `navigate_option` followed by a stale `cursor_update` with conflicting indices. ``` Pattern: navigate_option cursor=X->Y ... cursor_update cursorIndex=X (reverted) Root cause: PTY confirmation overwrites optimistic update Fix: cursor authority system (A3) — optimistic suppresses PTY within 200ms ``` ### 2b. False Idle `option_prompt` followed by `idle` within 500ms. ``` Pattern: option_prompt (N options) ... idle_detected (< 500ms gap) Root...