The non-streaming Anthropic path leaked OpenAI chat.completion bodies to
Claude clients when the upstream provider forces streaming (forced
SSE->JSON path): parseSSEToOpenAIResponse yields choices[] which Claude
Code cannot parse. Convert to Claude Messages shape for sourceFormat
CLAUDE in sseToJsonHandler.
Shared toClaudeMessageShape/openAICompletionToClaudeMessage moved to
translator/concerns/claudeShape.js to avoid circular import between
nonStreamingHandler and sseToJsonHandler. 5 new tests: sse-to-json
reassembly + Claude guard, plus existing anthropic-nonstream-shape
updated to import from the concern.
BUG: Anthropic client (sourceFormat=CLAUDE) hitting a claude-target provider
got a raw OpenAI chat.completion body on non-streaming requests. The
needsTranslation(CLAUDE,CLAUDE) gate is false when target===source, so the
translator never ran; a claude-transport executor replying OpenAI JSON
(opencode/big-pickle) leaked choices[]/prompt_tokens to the client, which
Anthropic SDKs cannot parse (no content[] blocks, no type:"message").
FIX: shape-aware guard toClaudeMessageShape() in nonStreamingHandler — when
sourceFormat is CLAUDE, convert any OpenAI-shape body to a proper Claude
message (type, content blocks with thinking/text/tool_use, stop_reason via
finish mapping, usage input/output tokens). Claude-shaped bodies pass through.
Also: strip <|im_end|>/<|endoftext|>/<|eot_id|> EOS sentinels from Claude
text deltas in openai-to-claude and kiro-to-claude translators — the upstream
EOS token leaks into the final text_delta (observed 'OK<|im_end|>').
Tests: anthropic-nonstream-shape.test.js (6: eos strip + shape guard incl
tool_calls→tool_use, pass-through, finish mapping). 28/28 related tests green.
asepharyana