fix(server): separate assistant provider items

[t3-code]

summary

• keep assistant output items with different provider item ids as separate messages
• track streaming segments per provider item so interleaved deltas stay attached correctly
• finalize every open item at approval boundaries and only the matching item at completion
• add regression coverage for multi-item, interleaved, approval, and completion sequences

testing

• vp test apps/server/src/orchestration/Layers/ProviderRuntimeIngestion.test.ts (60 passed)
• vp run t3#typecheck
• vp lint apps/server/src/orchestration/Layers/ProviderRuntimeIngestion.ts apps/server/src/orchestration/Layers/ProviderRuntimeIngestion.test.ts --deny-warnings
• vp fmt --check apps/server/src/orchestration/Layers/ProviderRuntimeIngestion.ts apps/server/src/orchestration/Layers/ProviderRuntimeIngestion.test.ts

request provenance

• requested by: @maria-rcks

---

Note

Medium Risk
Changes core orchestration message projection for multi-item assistant turns and approval boundaries; behavior is well covered by new tests but affects how thread messages are built from provider events.

Overview
Provider runtime ingestion now tracks assistant message segments per provider item within a turn, instead of one active assistant message for the whole turn.

The segment cache becomes a map keyed by item base key (derived from the event), so multiple content.delta streams in one turn land on distinct messages, interleaved deltas still merge into the correct item, and :segment:N splits after approval stay scoped to that item only.

At approval / user-input pauses, finalizeActiveAssistantSegmentsForTurn flushes every open item. item.completed finalizes only the matching item and leaves other in-flight items streaming. Regression tests cover multi-item turns, interleaving, overlapping completions, and whitespace-only approval edges.

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Note

Separate assistant provider items in ProviderRuntimeIngestion

• Changes the per-turn assistant segment cache from a single shared state to a map keyed by item base key, so each provider item gets its own message and independent segment sequence.
• Reworks message resolution so events reuse an active message only for their own base key; events from different items start their own segments instead of merging.
• Updates finalizeAssistantSegmentsForTurn to iterate over every active segment state at approval/pause boundaries rather than finalizing only one.
• Makes item completion finalize only the matching item while preserving other overlapping item streams, and applies fallback completion text to the latest matching empty message.
• Behavioral Change: hasAssistantMessageForTurn helper is removed; callers in ProviderRuntimeIngestion.ts now use item-scoped message selection. Completion no longer clears all segment state for the turn—only the matching item's active state is cleared.

^{Macroscope summarized b07e637.}

[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	13.6 KiB	13.6 KiB	−12 B (−0.1%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.0 KiB	7.0 KiB	0 B (0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.6 KiB	6.5 KiB	−12 B (−0.2%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	57.1 KiB	57.0 KiB	−44 B (−0.1%)	66.4 KiB	✅
Codex	Live turn messages	10	9	−1 (−10.0%)	21	✅
Claude	Total thread wire	13.6 KiB	13.6 KiB	−52 B (−0.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.0 KiB	7.0 KiB	−3 B (−0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.6 KiB	6.5 KiB	−49 B (−0.7%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.9 KiB	57.8 KiB	−44 B (−0.1%)	66.4 KiB	✅
Claude	Live turn messages	10	9	−1 (−10.0%)	21	✅

Baseline: f6db420 · PR result: b07e637 · 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: 113.8 KiB
• Claude decoded thread snapshot: 114.5 KiB

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

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 2 potential issues.

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[macroscopeapp]

Approvability

Verdict: Approved at b07e637

Macroscope's review found this PR approvable — This is a localized orchestration bug fix that keeps assistant output separated by provider item and correctly finalizes interleaved or approval-paused streams. Regression coverage addresses the affected sequences, with no schema, default, infrastructure, or sensitive-package changes.

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