[BUG] Agent accumulated 51 images via read tool, session bricked by provider 50-image count limit with no recovery

Description

Agent bricked its own session by accumulating images, user got stuck and cannot chat anymore.

Session ses_f9337a042ffebyl9CiHpjtKvlu titled Facetworks (816 messages, 3377 parts) ended in an unrecoverable loop:

Error from provider (Console Go): Upstream request failed: [invalid_request_error] request contains 51 images, exceeding the maximum of 50 allowed per request

Full error from DB:

• statusCode 400, isRetryable False
• responseBody: {"model":"muse-spark-1.3-contributor","error":{"param":null,"type":"invalid_request_error","message":"Error from provider (Console Go): Upstream request failed: [invalid_request_error] request contains 51 images, exceeding the maximum of 50 allowed per request"}}
• metadata url: https://opencode.ai/zen/go/v1/responses
• first failure 2026-09-05T13:13:44Z, then every retry fails identically including plain user messages.

What exactly happened, verified from local ~/.local/share/opencode/opencode.db:

• 51 parts with image attachments in this session
• 48x read tool reading screenshots: /tmp/profile-readme/covers/*.png, /tmp/undertow-shot*.png, /tmp/lichen-*.png, /tmp/abyss-shot*.png, /tmp/drift-shot*.png, /tmp/facet-wide.png, /tmp/facet-mobile.png, /tmp/gummy-*.png, /tmp/jelly-thumb.jpg, /tmp/src-check.png, plus projects/lichen/docs/screenshot.png and projects/drift/docs/screenshot.png
• 3x huggingface_gr1_z_image_turbo_generate outputs with mime image/webp attachments
• Agent was doing visual verification loops across undertow, lichen, abyss, drift, facetworks, gummy. User did not paste 51 images manually.

Why it is bricked:

• History already contains 51 images, so every subsequent LLM call fails before the model runs.
• User tried okay continue now?, use less images then, can something be done? - all failed with the same 51-image error.
• No way to /compact, fork without images, prune old tool attachments, or delete messages from TUI to recover.

Expected:

• OpenCode should enforce a client-side image budget before hitting the provider (warn, stop attaching old images, downscale to text placeholder, or auto-prune oldest image attachments).
• Compaction and retry paths should strip or summarize images so a session never becomes permanently dead.
• Provide recovery: remove message, fork from message without images, or compact that excludes image bytes.

Related but not duplicates (all size or invalid file, not count):

• #14562 Request Entity Too Large with images blocks session, compaction also fails
• #21668 Session dead when image exceeds 5 MB limit
• #9512 Trying to read an invalid image file bricks the session
• #13865 request_too_large pixels image

Plugins

No response - stock build agent with huggingface MCP image tool available

OpenCode version

1.18.27 at session time, binary now 1.18.29

Steps to reproduce

1. Start session on opencode-go/muse-spark-1.3-contributor variant xhigh in a repo with browser screenshot workflow
2. Let agent iteratively take screenshots to /tmp and read them for visual check (repeat 40+ times) plus a few image generations
3. Once attachment count in history exceeds 50, next step fails with 400 invalid_request_error
4. Send any follow-up message, it fails with the same error. Session cannot continue.

Screenshot and/or share link

No share link, private code. Error text above is verbatim from session message msg_071b40311001TNVEKL93snfrs2. Can provide DB part counts on request.

Operating System

Ubuntu 24.04.4 LTS, kernel 7.0.0-30-generic

Terminal

xterm-256color via OpenCode TUI/CLI