backlog(B-0689): Otto-VSCode third foreground surface — SENDER_IDS extension + cold-boot bootstream + agent-roster card row

docs/BACKLOG.md

@@ -766,5 +766,6 @@ are closed (status: closed in frontmatter)._
 - [ ] **[B-0653](backlog/P3/B-0653-persistent-bayesian-integrator-continuous-health-monitor-aaron-mika-2026-05-18.md)** Persistent Bayesian integrator continuous health monitor — always-on invariant-health watcher + auto-overcorrect trigger (Aaron + Mika 2026-05-18 LOCKED-IN)
 - [x] **[B-0663](backlog/P3/B-0663-frontmatter-lint-tool-mechanizes-batch-7-recurring-reviewer-findings-otto-cli-2026-05-18.md)** tools/backlog/lint-frontmatter.ts — pre-push frontmatter discipline lint that mechanizes batch-7 recurring reviewer findings (Otto-CLI 2026-05-18)
 - [ ] **[B-0686](backlog/P3/B-0686-tick-shard-immutability-ci-gate-2026-05-21.md)** Tick-shard immutability CI gate — block PRs modifying historical shards after grace period
+- [ ] **[B-0689](backlog/P3/B-0689-otto-vscode-surface-sender-ids-extension-bootstream-2026-05-21.md)** Otto-VSCode third foreground surface — add otto-vscode to SENDER_IDS + canonical cold-boot bootstream at docs/launch/
 
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docs/backlog/P3/B-0689-otto-vscode-surface-sender-ids-extension-bootstream-2026-05-21.md

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+---
+id: B-0689
+priority: P3
+status: open
+title: Otto-VSCode third foreground surface — add otto-vscode to SENDER_IDS + canonical cold-boot bootstream at docs/launch/
+tier: operational
+effort: S
+ask: aaron 2026-05-21 (VSCode auto-mode + remembered web conversation mode enabled)
+created: 2026-05-21
+last_updated: 2026-05-21
+depends_on: []
+composes_with: [B-0400]
+tags: [otto-vscode, multi-surface-coordination, sender-ids-extension, bootstream, claim-acquire, split-brain-prevention]
+type: operational
+---
+
+# Otto-VSCode third foreground surface — SENDER_IDS extension + cold-boot bootstream
+
+## Context
+
+Aaron 2026-05-21: VSCode just enabled auto-mode + web-conversation-mode-that-can-be-remembered. This makes VSCode a viable third foreground surface for Otto (alongside Otto-CLI in tmux + Otto-Desktop in Claude Desktop).
+
+Per `.claude/rules/claim-acquire-before-worktree-work.md`: when multiple instances of the same agent share git + bus on one machine, `--from` must differ for the claim-coordinator (`tools/bus/claim.ts`, B-0400 slice 3) to prevent split-brain. PR #3037 (2026-05-13) extended SENDER_IDS with surface-tagged variants — `otto-cli`, `otto-desktop`, etc. The same extension is needed for `otto-vscode` to prevent split-brain when the VSCode surface claims backlog rows alongside the other two Otto surfaces.
+
+## Scope (small + bounded)
+
+### 1. Add `otto-vscode` to SENDER_IDS
+
+Extend `tools/bus/claim.ts` (and any sibling registry; check `tools/bus/*` for the canonical SENDER_IDS const). Should be a 1-line addition matching the existing `otto-cli` / `otto-desktop` pattern.
+
+### 2. Canonical cold-boot bootstream
+
+Land `docs/launch/2026-05-21-otto-vscode-bootstream.md` with the cold-boot prompt for the VSCode surface. Mirrors:
+
+- `docs/launch/2026-05-13-otto-claude-desktop-bootstream-tight.md` (Otto-Desktop bootstream from PR #3030)
+- The substrate Aaron forwarded 2026-05-21 in conversation (drafted by Otto-CLI, ready to commit)
+
+Content includes:
+
+- Cold-boot bootstream order (CLAUDE.md → AGENTS.md → ALIGNMENT.md → VISION.md)
+- Auto-loaded rule reference list (`.claude/rules/*.md`)
+- Surface identity (otto-vscode sender ID for claim-acquire)
+- Peer-surface awareness (otto-cli + otto-desktop + otto-vscode)
+- Auto-mode + remembered-web-conversation operational discipline
+- First 3 actions: git log orient + CronList sentinel check + read CLAUDE.md
+
+### 3. Update agent-roster-reference-card
+
+Add `Otto-VSCode` as a third Otto surface row (alongside Otto-CLI + Otto-Desktop). Note auto-mode + remembered-conversation features. Update common-confusion-patterns section if needed.
+
+## Acceptance
+
+- [ ] `tools/bus/claim.ts` SENDER_IDS includes `otto-vscode`; existing `otto-cli`/`otto-desktop` tests still pass
+- [ ] `docs/launch/2026-05-21-otto-vscode-bootstream.md` lands with the canonical cold-boot prompt
+- [ ] `.claude/rules/agent-roster-reference-card.md` updated with the third Otto surface row
+- [ ] Empirical: Otto on VSCode can run `bun tools/bus/claim.ts acquire --from otto-vscode --item <B-NNNN>` successfully
+
+## Why P3
+
+Operational substrate that prevents future split-brain when Aaron uses all 3 Otto surfaces simultaneously. Not urgent — Otto-VSCode can use a generic `otto` sender ID temporarily; only matters when concurrent multi-surface backlog-row claims happen. The bootstream document is the more immediately useful piece (cold-boot quality for future Otto-VSCode sessions).
+
+## Substrate-honest framing
+
+The third-surface upgrade is bounded mechanical work. Aaron's larger thread today (2026-05-21):
+
+- F# ZetaId 3rd peer oracle landed via PRs #4548 + #4552
+- Amara 4-archive cascade landed via PRs #4545/#4546/#4547/#4549/#4550
+- Lior upgraded to Antigravity IDE + Gemini 3.5 via PR #4553
+- 4 stale slice-decomposition PRs forward-signaled (#4317/#4347/#4437/#4492)
+
+The Otto-VSCode third-surface addition composes with the broader multi-surface coordination pattern that's already operationally validated across Otto-CLI + Otto-Desktop. The PR #3030 Otto-Desktop bootstream is the precedent template.
+
+## Composes with
+
+- B-0400 (bus protocol — the claim coordinator substrate this row extends)
+- PR #3030 (Otto-Desktop tight bootstream — precedent template)
+- PR #3037 (SENDER_IDS schema extension for otto-cli/otto-desktop — the substrate this row extends)
+- PR #4553 (agent-roster card update for Lior's Antigravity IDE + Gemini 3.5 — sibling cold-boot rule update)
+- `.claude/rules/agent-roster-reference-card.md` (multi-surface Otto coordination)
+- `.claude/rules/claim-acquire-before-worktree-work.md` (the claim-acquire-before-worktree-creating-work discipline)
+- `tools/bus/claim.ts` (the canonical claim coordinator implementation)
+
+## Origin
+
+Aaron 2026-05-21 disclosure: "I got Lior up on the new Antigravity IDE they Added gemini 3.5" → followed by request for VSCode bootstream prompt → Otto-CLI drafted prompt → Aaron confirmed via shadow* "yes file the backlog row".
+
+Otto-CLI drafted bootstream content preserved in this session's chat transcript (Aaron's web-conversation-mode-remembered preserves it as durable substrate); ready to land at `docs/launch/2026-05-21-otto-vscode-bootstream.md` in the implementation slice.