[juliusmarminge]

Shell subscriptions and ~9 internal callers read every thread's shell row, then filtered in JS.

Measured read-only on a real DB (2,923 threads):

Path	Before	After
Shell subscription, both opt-ins (current clients)	~560 ms, +51 MB, 10 MB JSON built	~190 ms, +23 MB (128 threads sent)
Shell subscription, idle-subagents only	~560 ms, +51 MB	~230 ms, +32 MB
Startup thread count	~580 ms	7 ms
Startup bootstrap	~580 ms	60 ms
Agent awareness relay	~580 ms	~230 ms
Branch rename (per pass)	full shell	that worktree only (~150 ms on the busiest)
Project delete	full shell	that project only

• listActiveShellIndex() reads a few fields per active thread plus a broad mayBeLive flag; full shells are built only for threads a subscriber can receive, inside one read transaction.
• Snapshot output is byte-identical to main for all four opt-in combinations (static DB copy).
• Index check runs in 6 existing ProjectionStore cases; 5 fail if mayBeLive is forced false.

---

Claude Opus 5.5 in T3 Code (Claude Code harness).

🤖 Generated with Claude Code

[macroscopeapp]

Approvability

Verdict: Approved at 7adc73b

Macroscope's review found this PR approvable — This optimizes sidebar snapshots and startup reads by fetching only relevant thread shells and counting threads directly in SQL. Existing subscriber options and operation scopes remain unchanged, with reported snapshot-equivalence checks supporting the limited behavioral risk.

Notes:

• No code objects were reviewed. Approvability was decided on eligibility alone.

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	5.0 KiB	5.0 KiB	0 B (0.0%)	6.8 KiB	✅
Codex	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Codex	Live turn WebSocket wire	1.3 KiB	1.3 KiB	0 B (0.0%)	2.0 KiB	✅
Codex	Live turn WebSocket decoded	21.6 KiB	21.6 KiB	0 B (0.0%)	24.4 KiB	✅
Codex	Live turn messages	2	2	0 (0.0%)	8	✅
Claude	Total thread wire	5.0 KiB	5.0 KiB	+29 B (+0.6%)	6.8 KiB	✅
Claude	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Claude	Live turn WebSocket wire	1.2 KiB	1.3 KiB	+29 B (+2.3%)	2.0 KiB	✅
Claude	Live turn WebSocket decoded	21.9 KiB	21.9 KiB	+41 B (+0.2%)	24.4 KiB	✅
Claude	Live turn messages	1	2	+1 (+100.0%)	8	✅

Baseline: 08a463e · PR result: 7adc73b · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[coderabbitai]

No actionable comments were generated in the recent review.

Recent review info

Run configuration

• Source mode: Auto
• Repository: pingdotgg/t3code
• Branch: perf/shell-subset-reads
• File: .coderabbit.config.ts
• Commit: 7adc73b
• Layers: Repository TS config
• Review profile: CHILL
• Plan: Team
• Run ID: c41c6308-b2ff-4ecb-9010-bccc369287e2

Commits

Reviewing files that changed from the base of the PR and between 5c828e3 and 7adc73b.

Files selected for processing: 1

• apps/server/integration/transferBudgetV2.integration.test.ts

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 8 remain after this review.

Walkthrough

The change adds thread-count and active-shell-index APIs. Subscriber snapshot loading uses the index to select shell data before decoding and applies subscriber trim options. Startup, relay, project, and thread-launch paths use the new APIs or scoped snapshots.

Changes: Active Shell Index and Subscriber Snapshots

Layer / File(s)	Summary
Add the active shell index API apps/server/src/orchestration-v2/ProjectionStore.ts, apps/server/src/orchestration-v2/Orchestrator.ts, apps/server/src/orchestration-v2/ThreadManagementService.ts, apps/server/src/orchestration-v2/ProjectionStore.test.ts, apps/server/src/orchestration-v2/ProviderTurnControlService.test.ts	The projection store counts non-deleted threads, including archived threads, and lists active shell entries with a mayBeLive flag. The orchestrator and thread-management service expose both methods. Tests compare index entries with shell snapshots and update the relevant mock.
Select and trim subscriber snapshots apps/server/src/orchestration-v2/ShellStream.ts	The loader uses index entries to select threads before reading shell data when trimming is enabled. Shared trim logic applies idle-subagent and older-settled filters.
Use the loader in HTTP and WebSocket routes apps/server/src/orchestration-v2/http.ts, apps/server/src/ws.ts, apps/server/src/ws.test.ts	Both routes use the shared loader with subscriber options. They enrich projects from the returned snapshot; the WebSocket path also uses the returned subagent IDs.
Update other thread snapshot and index callers apps/server/src/orchestration-v2/ThreadLaunchService.ts, apps/server/src/project/ProjectService.ts, apps/server/src/relay/AgentAwarenessRelay.ts, apps/server/src/relay/AgentAwarenessRelay.test.ts, apps/server/src/serverRuntimeStartup.ts, apps/server/src/serverRuntimeStartup.test.ts, apps/server/src/serverRuntimeStartup.autoPull.test.ts, apps/server/integration/transferBudgetV2.integration.test.ts	Startup telemetry uses the thread count, and auto-bootstrap searches the active-shell index. Other callers use project- or worktree-scoped snapshots, or request active top-level shells for the relay’s initial snapshot.

Priority: Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Refactor

Sequence Diagram(s)

sequenceDiagram
  participant SubscriberRoute
  participant loadSubscriberShellSnapshot
  participant listActiveShellIndex
  participant readThreads
  SubscriberRoute->>loadSubscriberShellSnapshot: Pass trim options and readers
  loadSubscriberShellSnapshot->>listActiveShellIndex: Read index when trimming is enabled
  listActiveShellIndex-->>loadSubscriberShellSnapshot: Return active shell entries
  loadSubscriberShellSnapshot->>loadSubscriberShellSnapshot: Select thread IDs and compute trim facts
  loadSubscriberShellSnapshot->>readThreads: Read selected thread IDs
  readThreads-->>loadSubscriberShellSnapshot: Return shell data
  loadSubscriberShellSnapshot-->>SubscriberRoute: Return trimmed snapshot and subagent IDs

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Possibly related issues

• [Bug]: Thread-shell and recovery queries take 2–22 s on a 26.5 GB V2 database; six proposed indexes (follow-up to #22659) #23000 — The PR adds an active-shell index and targeted shell reads, which overlap with the issue’s shell-list read-cost objective. It does not add the proposed indexes.
• PR discovery rebuilds thread shells and counts unused history #18618 — The PR narrows shell reads to selected rows, but does not change ThreadPullRequestService.
• Thread list fails with "too many SQL variables" once a server has more than 32,766 threads, so no client can load or sync its sidebar #25621 — The PR changes shell reads in named caller paths, but the diff does not show whether it removes the SQL variable limit.
• History-wide reads saturate the single SQLite reader on large databases (thread switches take 12-50 s) #24895 — The PR reduces shell reads through index-based selection, but does not address the issue’s other recovery and canonical projection statements.
• Track performance audit fixes #9661 — The PR changes per-subscriber shell reads, which overlaps with the tracker’s S11 item. The tracker’s broader items are not fully addressed.

Suggested reviewers: t3dotgg, maria-rcks

Merge Risk: Minimal · up to 7adc7

The reviewed test mock change does not introduce a merge-blocking behavior or integration risk.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title clearly and concisely summarizes the primary performance improvements: faster sidebar shell loading and startup thread counting.
Description check		The description clearly explains the problem, implementation approach, measured performance improvements, snapshot equivalence, and verification coverage. It does not include an explicit Scope and app…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Description check

Explanation

The description clearly explains the problem, implementation approach, measured performance improvements, snapshot equivalence, and verification coverage. It does not include an explicit Scope and approval section or linked approval evidence, but the core description is mostly complete and relevant.

Finishing Touches

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Dismissing prior approval to re-evaluate 7adc73b