ai: image sizing can exceed maxRatio or produce NaN #59536

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1. opencode-agent commented on Oct 27, 2026

   

   opencode-agentBot

   on Oct 27, 2026 – with OpenCode Agent

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   Thanks for the detailed report. I reproduced both problems on the latest dev (6aedf36) by calling the image-sizing code directly:

   • ImageSizing.fit({ aspect: "1:3", resolution: "1.5K" }) with the gpt-image limits (maxRatio: 3) returns 880x2656, which is 3.018:1 and over the limit.
   • fit with aspect 1:0 or 0:1 (and { multiple: 16 }) returns { width: NaN, height: NaN }, and ImageSizing.exact(...) still succeeds for those aspects.

   The script below reproduces it. Run it from packages/ai in a checkout. The open PR #59535 looks like it addresses this.

   Reproduction script (repro.ts)

   // Run from /workspace/repo/packages/ai: bun /workspace/repro/repro.ts  (REPO env overrides checkout path)
   import { Effect } from "effect"
   const repo = process.env.REPO ?? "/workspace/repo"
   const { ImageSizing } = await import(`${repo}/packages/ai/src/protocols/utils/image-sizing.ts`)
   
   const GPT_IMAGE_2 = { multiple: 16, maxEdge: 3840, minPixels: 655_360, maxPixels: 8_294_400, maxRatio: 3 }
   
   const s = ImageSizing.fit({ aspect: "1:3", resolution: "1.5K" }, GPT_IMAGE_2)
   const ratio = Math.max(s.width, s.height) / Math.min(s.width, s.height)
   console.log("fit 1:3 @1.5K (maxRatio 3):", s, "ratio", ratio.toFixed(4), ratio > 3 ? "EXCEEDS maxRatio" : "ok")
   
   for (const aspect of ["1:0", "0:1"]) {
     console.log(`fit ${aspect} (multiple 16):`, ImageSizing.fit({ aspect }, { multiple: 16 }))
     const route = { name: "test", unsupported: (field: string, msg: string) => new Error(`${field}: ${msg}`) } as any
     const r = await Effect.runPromise(Effect.result(ImageSizing.exact(route, { aspect }, { multiple: 16 })))
     console.log(`exact ${aspect}:`, JSON.stringify(r))
   }

   Run it: bun repro.ts
2. opencode-agent

   added

   reproduced

   on Oct 27, 2026