xAI: undersized images persist in history and prevent session recovery #54325

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1. github-actions

   assigned

   jlongster

   on Oct 10, 2026
2. opencode-agent commented on Oct 10, 2026

   

   opencode-agentBot

   on Oct 10, 2026 – with OpenCode Agent

   Contributor

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   Thanks for the clear report. I could confirm this on 2.0.25 and it still happens on the latest v2 commit (4617210).

   There are no xAI credentials here, so I tested the code that builds each request from the saved session history. A real 6x8 PNG returned by the read tool and stored in the history comes out unchanged and is still in the request for provider xai, on every later turn. The current xAI check in packages/core/src/session/model-request.ts only filters by format (so GIFs are handled, as in #53786). Nothing checks image width or height, so xAI's invalid_image ... too small error repeats on every turn, as you describe.

   The script below reproduces it. Related:

   • fix(core): apply the Grok image guard to Grok served by any provider #53803: applies the Grok image check when Grok is served by any provider
   • session: provider image rejection bricks session — generic 400 error, no recovery path #52042: the general problem of a provider rejecting an image and leaving the session stuck

   Reproduction script (xai-small-image.test.ts)

   // Reproduction for anomalyco/opencode#54325.
   // Run from an opencode v2 checkout:
   //   cp xai-small-image.test.ts <repo>/packages/core/test/ && cd <repo>/packages/core && bun test test/xai-small-image.test.ts
   //
   // A 6x8 PNG (xAI requires both sides >= 8px) returned by the read tool and stored in the
   // session history is passed unchanged to the xAI request on every later turn, so xAI
   // answers each turn with 400 invalid_image and the session cannot recover.
   import { expect, test } from "bun:test"
   import { Message, ToolResultPart } from "@opencode/ai"
   import { boundImages, unsupportedParts } from "@opencode/core/session/model-request"
   
   // Real 6x8 RGB PNG
   const PNG_6x8 =
     "iVBORw0KGgoAAAANSUhEUgAAAAYAAAAICAIAAABVpBlvAAAAEklEQVR4nGP4z8CAhtD5AyIEAGL6L9EoaAtUAAAAAElFTkSuQmCC"
   
   test("#54325: undersized image in saved history is still sent to xAI", () => {
     const history = [
       Message.user([Message.text("Read tiny.png")]),
       Message.tool(
         ToolResultPart.make({
           id: "call_1",
           name: "read",
           result: {
             type: "content",
             value: [
               { type: "text", text: "Image read successfully" },
               { type: "file", uri: `data:image/png;base64,${PNG_6x8}`, mime: "image/png", name: "tiny.png" },
             ],
           },
         }),
       ),
       Message.user([Message.text("Please recover: resize the image")]),
     ]
     const capabilities = { tools: true, input: ["text", "image"], output: ["text"] }
   
     // Same pipeline the request assembly uses: boundImages(unsupportedParts(..., "xai"))
     const sent = boundImages(unsupportedParts(history, capabilities, "xai"))
   
     const result = sent[1]?.content[0] as any
     const file = result.result.value.find((item: any) => item.type === "file")
     console.log("tool-result parts sent to xAI:", JSON.stringify(result.result.value.map((i: any) => i.type)))
     // BUG: the 6x8 image is still included; xAI rejects it with
     // "invalid_image: Image dimensions 6x8 are too small. Both width and height must be at least 8 pixels."
     expect(file).toBeDefined()
     expect(file.uri).toBe(`data:image/png;base64,${PNG_6x8}`)
   })

   Run it: bun xai-small-image.test.ts
3. opencode-agent

   added

   reproduced

   on Oct 10, 2026