fix(server): stop storing tool image bytes no client reads

[derektrimm]

Fixes #16647

A tool that reads or captures an image returns the whole file as base64, and the turn item carrying it is written twice: to orchestration_events and to orchestration_v2_projection_turn_items. One Claude Read of a 114 KB PNG stores 153,028 bytes in each table. Nothing reads them back. A read file's preview loads from viewedImagePath, and context handoff skips tool items. The only image bytes a client fetches are the blocks toolOutputImages finds, served as tool-output-image assets (#16199).

When the ingestor normalizes a dynamic_tool turn item, every other base64 image body is replaced with its decoded sizeBytes, keeping type and mime type. This covers Claude's structured Read result (file.base64), Grok's ImageContent, Cursor image parts (mime type optional), and MCP or Claude image blocks past the served positions. Served blocks are kept whole, so tool screenshots still render.

• Strings that are not a base64 body are kept, so ids, inline SVG and data URLs under the same keys survive.
• The size is measured from the removed body, never taken from a provider field.
• An item without such bytes is returned by reference; containers are copied only when a descendant changes.
• Each block keeps its own shape (type, mime type and any provider metadata such as dimensions) with sizeBytes added, rather than a new marker shape, so nothing that reads those fields changes.
• toolOutputImageBlocks and the asset route's MAX_TOOL_OUTPUT_IMAGE_BASE64_LENGTH move into @t3tools/shared/toolOutput, so persistence and the asset route agree on which blocks are served. A block in a served position that is larger than the route serves is stripped too.

Verification

Reproduced on main (72d5c32) with vp run dev against a snapshot of a real 9 GB database, asking Claude Sonnet 5.5 to Read a 114 KB PNG, then reading both tables with sqlite3. Same prompt with this change:

	orchestration_events	orchestration_v2_projection_turn_items	whole thread
main	153,028 B	153,028 B	356,447 B
this PR	1,319 B	1,319 B	47,528 B

The stored sizeBytes was 113,787, the file's size. The expanded Read row shows the same image preview before and after.

In that database's history, image-bearing tool rows total 2,313 MiB: 2,271 MiB are in the removed class and 42 MiB are screenshots the asset route serves. Existing rows are not rewritten; this stops the growth going forward.

Tests:

• vp test run apps/server/src/orchestration-v2/toolOutputImageBytes.test.ts apps/server/src/orchestration-v2/ProviderEventIngestor.test.ts: 26 passed. The ingestor test reads the event log and projection back from SQLite.
• Each of these breaks fails the intended tests: removing the ingestor call, removing the served exception, stripping any string, trusting a supplied size, dropping the base64 key, dropping Cursor's image part, dropping mime types under type, and keeping a served-position image larger than the asset route serves.
• toolOutput, WireProjection, AssetAccess and client itemDetail tests pass unchanged (106 total). tsc --noEmit passes in apps/server and packages/shared.

Not checked: Grok, Cursor and ACP shapes were tested from fixtures taken from stored data, not from live turns. A served screenshot was tested through the ingestor and the asset reader, not through a live MCP screenshot turn.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR changes durable production data by recursively removing image bodies from dynamic-tool outputs while preserving asset-served screenshots. The provider-specific traversal and cross-component persistence/asset contract are nontrivial, so the change merits human review.

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📒 Files selected for processing (4)

• apps/server/src/assets/AssetAccess.ts
• apps/server/src/orchestration-v2/toolOutputImageBytes.test.ts
• apps/server/src/orchestration-v2/toolOutputImageBytes.ts
• packages/shared/src/toolOutput.ts

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📝 Walkthrough

Walkthrough

Dynamic tool outputs now omit qualifying base64 image bytes that are not selected for tool-output-image assets. The normalizer records the measured size of removed bytes. Selected image blocks remain available for extraction.

Changes

Tool output image handling

Layer / File(s)	Summary
Select image blocks and share the size limit packages/shared/src/toolOutput.ts, apps/server/src/assets/AssetAccess.ts	toolOutputImageBlocks selects up to MAX_TOOL_OUTPUT_IMAGES supported image blocks. toolOutputImages uses those blocks, and the asset route uses the shared base64 size limit.
Strip unserved image bytes apps/server/src/orchestration-v2/toolOutputImageBytes.ts, apps/server/src/orchestration-v2/toolOutputImageBytes.test.ts	The helper removes qualifying base64 fields from unserved image bodies and replaces them with measured sizeBytes. Tests cover supported shapes, size and count limits, unchanged non-image data, and reference preservation.
Apply stripping during event normalization apps/server/src/orchestration-v2/ProviderEventIngestor.ts, apps/server/src/orchestration-v2/ProviderEventIngestor.test.ts	turn_item.updated normalization passes items through the stripping helper. The ingestion test checks that Read image bytes are stripped and screenshot image bytes remain extractable.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix · Severity of issue fixed: Low

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 8773f

The change stops storing image bytes that no client reads and keeps images served as assets intact. No merge-blocking risk is evident.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 8773f

The change reduces unnecessary image retention while preserving existing image-selection limits and asset identifiers. No introduced security weakness was identified, but removed data cannot be recovered by reverting the change, and compatibility across every producer has not been fully established.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — Tool-controlled image output reaches event and projection storage through normalization. The PR reduces qualifying retained bodies on that path; it does not expand the set of client-fetchable image positions or introduce additional asset authority. The examined exposure remains scoped by the stored thread, turn item, and image index.

Trust Boundaries and Controls

• observed — The existing supported-image MIME check, size rejection, server-side item lookup, and thread/item/index claim construction remain in place. The base-to-head asset-access change moves only the identical size-limit definition and its import; it does not weaken these controls. Broader authorization middleware was not independently audited.

Resilience and Maintainability Implications

• observed — Existing guarded writes recheck current run-attempt or provider-thread ownership inside the transaction before committing. Normalized payloads pass through these same guards, and event publication remains ordered after commit. No new cross-store image-deletion workflow is introduced.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	For #16647, the ingestor strips unserved image bodies before persistence, so the normalized item feeds both the event log and projection. The helper replaces image bodies with measured sizeBytes and…
Out of Scope Changes check	✅ Passed	The changes to toolOutputImageBlocks, the shared size limit, and AssetAccess keep persistence selection consistent with the asset route. The added tests cover these behaviors. No unrelated change …
Approvability	✅ Passed	This is a focused bug fix, not a product-default change or a large refactor. It changes six files; the production change adds one image-byte stripping helper and shares image-selection logic. It does …
Title check	✅ Passed	The title clearly summarizes the main change: stop storing tool image bytes that clients do not read.
Description check	✅ Passed	The description explains the problem, change, and focused verification in detail, and links issue #16647. It does not state explicit maintainer approval or explain why the change qualifies without app…

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Inline comments:
Review comments at @packages/shared/src/toolOutput.ts:
- Around line 226-238: Update toolOutputImageBlocks to exclude supported image
blocks whose base64 data exceeds the asset route’s encoded-size limit before
adding them to the result. Derive the encoded-length bound from the provider
image byte limit so the selected images and their asset indexes remain aligned.

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📥 Commits

Reviewing files that changed from the base of the PR and between 517188b and 3c84157.

📒 Files selected for processing (5)

• apps/server/src/orchestration-v2/ProviderEventIngestor.test.ts
• apps/server/src/orchestration-v2/ProviderEventIngestor.ts
• apps/server/src/orchestration-v2/toolOutputImageBytes.test.ts
• apps/server/src/orchestration-v2/toolOutputImageBytes.ts
• packages/shared/src/toolOutput.ts

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