[Bug]: Assistant-provided images never render inline in chat

[brahimhamichan]

Before submitting

• I searched existing issues and did not find an open duplicate.
• I included a deterministic reproduction and compared it with related closed work.

Area

apps/web / apps/desktop chat timeline

Steps to reproduce

Ask an assistant to create five simple numbered PNG files and return each through a different output path:

1. A native image content block (for example, output forwarded from the image viewing tool).
2. Markdown image syntax with an absolute local path: ![2](/tmp/embed-test/2.png).
3. Markdown image syntax with a data:image/png;base64,... URI.
4. An HTML <img> element with a data:image/png;base64,... source.
5. Markdown image syntax with a file:///tmp/embed-test/5.png URI.

The PNGs can be tiny 160 × 160 white cards containing only their respective number.

Expected behavior

At least the native image content block should render directly in the assistant response. Workspace/local images should use the existing signed asset route when appropriate. Supported inline data images should either render or clearly document that they are intentionally unsupported.

Image output should remain visible after the turn settles rather than being hidden inside collapsed tool activity.

Actual behavior

None of the five images is visible:

• The native image block is absent from the visible assistant response and appears to be hidden with tool activity under the collapsed Worked for … row.
• The absolute local path renders an Image unavailable · 2 placeholder.
• The Markdown data URI renders Image unavailable · 3.
• The HTML data URI renders Image unavailable · 4.
• The file:// Markdown source renders Image unavailable · 5.

A private GitHub blob URL also previously rendered only as broken image alt text, although that may be a separate authentication limitation.

Impact

Agents cannot provide implementation screenshots, generated images, or other visual evidence inline. This makes visual review workflows unreliable because the assistant believes it embedded the image while the user sees no image.

Version or commit

T3 Code Alpha, observed 2026-09-01. Exact build identifier was not visible in the captured thread.

Environment

T3 Code desktop/web client on macOS, connected to a Linux-hosted workspace.

Logs or stack traces

No visible error was shown. Markdown image nodes rendered terminal Image unavailable placeholders.

Screenshots, recordings, or supporting files

A screenshot is available showing all four Markdown/HTML variants as Image unavailable and no visible native image block. It can be added as a follow-up because gh issue create cannot upload a local attachment into the issue body.

Related work

• [Feature]: Codex image generation support #2398 described Codex-generated images and view_image output not appearing inline. It was closed as completed.
• Fix inline Markdown image previews in chat #4785 directly implemented inline Markdown image previews and workspace-local signed asset resolution, but the PR was closed without merging.
• Pull request viewer does not load images from private repositories #6600 covers authenticated private-repository images in the PR viewer, which is adjacent but a different surface.

Workaround

No inline workaround was successful. The user must receive a file path and open the image outside the conversation.

[brahimhamichan]

Reproduction screenshot

The screenshot below shows the settled assistant response in T3 Code Alpha. The native image block is absent, while all four Markdown/HTML delivery variants render terminal Image unavailable placeholders.

Observed results:

• Method 1: native image block not visible in the settled response.
• Method 2: absolute local path → Image unavailable · 2.
• Method 3: Markdown data URI → Image unavailable · 3.
• Method 4: HTML data URI → Image unavailable · 4.
• Method 5: file:// Markdown → Image unavailable · 5.