WebP image causes infinite token generation loop + hallucinated image content

Environment

• Claude Code v2.1.55
• Model: Opus 4.6 (Claude Max)
• OS: Windows 11
• Also reproduced hallucination on claude.ai web

Bug 1: Claude Code — WebP image processing causes token overflow

Steps to Reproduce

1. Open Claude Code, /clear to start fresh (first message in session)
2. Paste a .webp image and send a prompt asking to process the image
3. Claude Code starts generating but never produces useful output

Actual Behavior

• Claude hits 32000 output token maximum API error
• Appears to be stuck in a loop attempting to describe/process the image
• This has happened multiple times with the same pattern — not a one-off

Expected Behavior

• Either: successfully process the webp image
• Or: report that the image format is unsupported / failed to load

Bug 2: Claude.ai Web — Hallucinated image content from pasted conversation log

Steps to Reproduce

1. Copy the Claude Code conversation log (which contains [Image #3] text placeholder)
2. Paste it into a new claude.ai web conversation to ask about the failure
3. Claude.ai treats the [Image #3] text as if a real image exists

Actual Behavior

Claude.ai:

• Repeatedly claims "I can see the image", "Let me examine it carefully"
• Self-reinforcing loop: each attempt adds more false confidence
• Fabricates specific, detailed content: invented 12 university courses with names, time slots, and semester dates
• Actually generates and writes an ICS file with entirely fabricated data
• Never admits it cannot see any image

Expected Behavior

• Recognize that [Image #3] is a text placeholder, not an actual image
• Respond: "I don't see an actual image in this conversation"

Evidence

Claude.ai hallucination conversation (shared link):

https://claude.ai/share/2be6353c-a86e-4b41-9572-c328cb79c5f4

Claude Code raw output:

 ▐▛███▜▌   Claude Code v2.1.55
▝▜█████▛▘  Opus 4.6 · Claude Max
  ▘▘ ▝▝    C:\Users\[REDACTED]

❯ /clear
  ⎿  (no content)

❯ [user prompt + webp image pasted]
  ⎿  [Image #3]
  ⎿  API Error: Claude's response exceeded the 32000 output token maximum.

Analysis

Bug 1 may be a webp decoding issue — the image is present but Claude Code cannot process it, yet instead of failing gracefully, it enters an infinite generation loop.

Bug 2 is a hallucination triggered by strong user intent combined with the [Image #3] text marker. The model assumes an image must exist because the user references one, then fabricates increasingly specific details through a self-reinforcing loop. This is particularly dangerous because it produces confident, detailed, actionable output (a real .ics file) based on entirely fabricated data.

Impact

• Data integrity: Users may import fabricated calendar data without realizing it's fake
• Trust: The hallucination is highly convincing — specific course names, times, room numbers
• Reproducibility: The Claude Code webp issue has occurred multiple times with the same pattern