fix(clients): chat images show the new file after an agent rewrites it

[ishaanko]

Fixes #15676.

When an agent rewrites a workspace image, a later assistant response or work entry can reuse the earlier signed URL and show cached bytes. This gives each assistant message or work entry its own client asset cache identity, including image previews and media actions on web and mobile. Scope stays out of the RPC payload, and the existing filesystem permission checks and environment routing stay in place.

Rebuilt from @ishaanko’s original contribution, preserving their commits and merging current main. Removed the duplicated asset test and redundant tool-output scopes; kept the existing work-log rendering and permission architecture.

Verification:

• One 65-line added test → one 41-line regression in the existing runtime suite. It checks separate signing requests across scopes, reuse within a scope, and resource-only arguments at the stub client boundary. The baseline counterfactual fails that last stub assertion; the real transport already strips unknown fields. The restored selection passes 71 tests, including the existing web/mobile asset permission cases.
• 143 focused tests across 11 existing files pass after merging current main, plus 874 existing mobile React Compiler coverage cases and 13 web Markdown asset/permission browser tests. Web, mobile (including the iOS modal) and client-runtime typechecks pass; scoped lint and formatting pass with existing warnings.
• Independent Claude Opus 5.5 and Codex GPT-6 Sol reviews found mobile media-link, native inline-image and iOS video scope omissions; those were fixed. Five full adversarial review rounds completed. Both final reviewers returned no code findings after the file-preview integration; the earlier test conflict resolution retains both cases. Both traced the new bot preview finding and confirmed that inline expansion uses the displayed URL, while media-link opening keeps main’s existing fresh-file behavior.
• Live headless Linux web: identical 1280×800 fixture, real timeline/Markdown/asset hooks and isolated server signing/serving. Pinned main web sources at ab6be13 show red/red after the file becomes blue; head shows red/blue with distinct URLs. Expanded second image is blue. In-place overwrite and atomic replacement both pass. Expanded reasoning entries and viewed-image tool entries also show the rewritten image independently.

Before — main reuses the old image in the later message:

After — the later message shows the rewritten blue image:

Recording: overwrite, later message and expanded preview

Additional head checks:

The timeline data above is an inert client projection fixture; file bytes and asset requests are real. This does not verify provider emission or persisted timeline updates. The final main integration retains the message-scoped lookups alongside main’s new refresh behavior for Markdown file previews. Chat renderings do not pass that preview mutation token; the captured chat behavior is unchanged. All 13 current Markdown asset/permission browser cases pass. A fallback font was injected for readable headless captures.

This change covers agent-authored assistant responses, reasoning and viewed-image work entries. User-authored Markdown, plan cards, item-inspector reasoning and event-detail Markdown keep their existing shared image URL behavior. Scope partitions cache identity; it does not snapshot historical bytes. Expiry, eviction, refresh, retry, opening a media link and Save/Copy/share reauthorization may load the current file, and atomic replacement can invalidate an earlier capability. Attachments and already unique tool-output images retain their existing identities.

Not verified live: macOS, Windows, Electron desktop, iOS, Android, remote/relay/tunnel connections, native image caches/gallery/video playback, web video playback and Save/Copy/download actions. Device verification is disabled in this environment. Native visual proof remains required before calling the mobile paths ready.

Implemented with GPT-6.1-sol through Codex in T3 Code; tests by GPT-6-astra through Codex; reviewed by Claude Opus 5.5 through Claude Agent and GPT-6-sol through Codex.

[macroscopeapp]

Approvability

Verdict: Approved at 5410f24

Macroscope's review found this PR approvable — This is a focused web/mobile bug fix that scopes client-side signed-asset caching per message or work entry while preserving the server RPC contract and existing unscoped behavior. An unresolved high-severity finding indicates expanded earlier images may still refresh to current file bytes, which remains a separate blocking correctness concern.

Notes:

• This verdict was updated automatically after the outstanding correctness findings were resolved. Macroscope did not re-review the code.

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• apps/mobile/src/features/threads/thread-work-log.tsx

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📝 Walkthrough

Asset URL queries now accept an optional client-side scope. Web and mobile rendering paths pass message or work-entry IDs as scopes. The client runtime excludes the scope from URL creation requests.

Changes: Scoped Asset URLs

Layer / File(s)	Summary
Scoped URL query and refresh packages/client-runtime/src/state/assets.ts, packages/client-runtime/src/state/assets.test.ts, apps/mobile/src/state/assets.ts, apps/web/src/assets/assetUrls.ts	Asset URL queries and refresh requests accept an optional scope. The client runtime uses it for query identity and excludes it from URL creation requests. Tests cover scoped query reuse and separation.
Web rendering scope propagation apps/web/src/components/ChatMarkdown.tsx, apps/web/src/components/chat/MessagesTimeline.tsx, apps/web/src/components/chat/ExpandedImageDialog.tsx, apps/web/src/components/media/MediaActions.tsx	Web Markdown receives scopes from message and work-entry IDs and passes them to asset lookups, refreshes, and media asset identity. Expanded video lookups use the asset scope.
Mobile message and work-log scopes apps/mobile/src/features/threads/ThreadMarkdownImage.tsx, apps/mobile/src/features/threads/ThreadFeed.tsx, apps/mobile/src/features/threads/thread-work-log.tsx	Mobile Markdown image rendering reads its scope from context. Assistant messages and work-log content provide message or work-entry IDs.

Priority: ⬇️ Low

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

Change: Bug fix · Severity of issue fixed: Low

Possibly related PRs

• pingdotgg/t3code#13218: Both changes add client-only asset URL scopes to distinguish cached URLs for rewritten chat images.

Suggested reviewers: juliusmarminge

Merge Risk: 🟡 Moderate · up to b3bc6

After an atomic file replacement, saving or copying an older displayed chat image can return the replacement image instead. Resolve this mismatch before merging.

Security architecture risk: 🔵 Low · up to b3bc6

This changes how image URLs are reused without establishing new file-access authority. No introduced security weakness was found in the inspected paths, but refresh, file replacement, and remount behavior have not been validated end to end.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The inspected change creates more independently cached signing opportunities for existing resources, not a new resource or environment selector. Existing media handling already accepts absolute host paths and permits a guarded fallback to a registered local environment after selected asset failures. Scope does not broaden those path classes or fallback conditions.

Trust Boundaries and Controls

• observed — Rendering scope remains local to query identity. On the inspected media-serving path, existing controls verify the token signature and expiry, require the signed basename and canonical path to match, and open the file using its signed identity. Scope is not interpreted as authority by those controls.

Resilience and Maintainability Implications

• inferred — Save/copy on web and resource-backed sharing on mobile obtain fresh, unscoped capabilities, so retrieved bytes can differ from an older cached display after a rewrite. These action paths already refreshed the same resources before this PR. The comparison does not establish newly introduced or materially worsened data exposure, and forwarding scope alone would not make mutable files immutable.

Pre-merge checks: 3 · 1 · 1

Failed checks: 1 warning · 1 inconclusive

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 15 functions across 11 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Linked Issues check		[#13138] The scoped URL changes address stale previews: web assistant messages and work entries, and mobile messages and work-log rows, use stable message or entry IDs. The client-runtime test checks …	Provide evidence that the desktop chat renderer uses the changed scoped asset path, or verify the overwrite-and-read behavior in the desktop app.

Passed checks: 3 passed

Check name	Status	Explanation
Out of Scope Changes check		The summarized changes are connected to [#13138]. They add URL scoping, pass message or work-entry IDs through image render paths, preserve scope for expanded media, and test scoped URL behavior. No u…
Title check		The title clearly identifies the main fix: chat images now show updated file content after an agent rewrites the file.
Description check		The description covers the problem, implementation, scope, linked issue, verification results, screenshots, recording, limitations, and agent attribution. It does not use the template's exact section …

Full details: Out of Scope Changes check

Explanation

The summarized changes are connected to [#13138]. They add URL scoping, pass message or work-entry IDs through image render paths, preserve scope for expanded media, and test scoped URL behavior. No unrelated changes are evident.

Full details: Description check

Explanation

The description covers the problem, implementation, scope, linked issue, verification results, screenshots, recording, limitations, and agent attribution. It does not use the template's exact section headings, but the required information is present and sufficiently detailed.

Full details: Linked Issues check

Explanation

[#13138] The scoped URL changes address stale previews: web assistant messages and work entries, and mobile messages and work-log rows, use stable message or entry IDs. The client-runtime test checks separate URLs for separate scopes, reuse for the same scope, and removal of scope from the server request. The issue reports the bug in the desktop app. The available evidence does not establish that the desktop chat renderer uses these scoped web or client-runtime paths, and the reported verification covers web and mobile.

Resolution

Provide evidence that the desktop chat renderer uses the changed scoped asset path, or verify the overwrite-and-read behavior in the desktop app.

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[coderabbitai]

Actionable comments posted: 1

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Inline comments:
Review comments at @apps/web/src/components/media/MediaActions.tsx:
- Line 29: Update actionUrl so Save and Copy image use the displayed image URL
while it remains valid; if it has expired, handle expiration explicitly rather
than refreshing to a URL that may return different image bytes. Passing
source.asset.scope to the forced refresh is not sufficient to preserve the
displayed image.

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📥 Commits

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📒 Files selected for processing (11)

• apps/mobile/src/features/threads/ThreadFeed.tsx
• apps/mobile/src/features/threads/ThreadMarkdownImage.tsx
• apps/mobile/src/features/threads/thread-work-log.tsx
• apps/mobile/src/state/assets.ts
• apps/web/src/assets/assetUrls.ts
• apps/web/src/components/ChatMarkdown.tsx
• apps/web/src/components/chat/ExpandedImageDialog.tsx
• apps/web/src/components/chat/MessagesTimeline.tsx
• apps/web/src/components/media/MediaActions.tsx
• packages/client-runtime/src/state/assets.test.ts
• packages/client-runtime/src/state/assets.ts

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[tth05]

This would also fix #15676. Would be nice if this gets merged

[juliusmarminge]

Taking over this one. I will integrate it with current main, retain the filesystem permission checks, and verify that later chat messages load rewritten workspace images. I will push the focused rebuild here while preserving @ishaanko’s commits.

Dismissing prior approval to re-evaluate 5410f24