Based only on the supplied evidence, a direct Claude Opus 4.7 vs GPT-5.5 Spud comparison is not fact-checkable: the OpenAI sources provided are a citation-formatting guide and a Deep Research guide, not a model-specific source for GPT-5.5 Spud ^[1][7]. What is supportable is narrower: OpenAI explicitly documents citation formatting and requires clearly visible, clickable inline citations for Deep Research outputs, while the supplied Anthropic sources document Claude Opus 4.7 as a flagship reasoning model and show workflow primitives such as files, prompt caching, and extended thinking, but do not in these excerpts show equally explicit end-user citation requirements ^{[1][7][4][2][3][8]}. Key findings - Anthropic describes Claude Opus 4.7 as part of its latest generation and as its most capable model for complex reasoning and agentic coding, with a “step-change jump” over Claude Opus 4 ^[4]. - Anthropic also states that Opus 4.7 uses a new tokenizer compared with previous models ^[5]. - For workflow inputs, Anthropic’s Files API lets developers upload and manage files for Claude API use without re-uploading the content on every request ^[2]. - For reasoning workflow mechanics, Anthropic documents special behavior for “thinking blocks” when using extended thinking with prompt caching ^[3]. Anthropic’s Claude Code docs also say that adding the word “ultrathink” to a skill enables extended thinking in that skill ^[8]. - On evidence provenance, OpenAI’s citation-formatting guide is explicitly about preparing citable material and instructing the model to format citations effectively ^[1]. - OpenAI’s Deep Research guide is more explicit about user-facing provenance: when web results, or information contained in those results, are shown to end users, inline citations should be clearly visible and clickable in the user interface ^[7]. - Inference: the Anthropic materials show building blocks that could support traceable research workflows, but the supplied excerpts do not explain how files, thinking blocks, or extended thinking are linked to user-visible citations or a source audit trail ^[2][3][8]. - For “scratchpads” specifically, the closest match in the supplied Anthropic evidence is “thinking blocks” under extended thinking ^[3]. The supplied OpenAI evidence does not describe a scratchpad mechanism; it focuses on citation formatting and Deep Research citation display requirements ^[1][7]. - Therefore, any claim that Claude Opus 4.7 or GPT-5.5 Spud is categorically better on citations, scratchpads, or end-to-end traceability would go beyond the supplied evidence. Insufficient evidence ^{[1][2][3][4][7][8]}. Evidence notes - The strongest provenance evidence in this set comes from vendor-primary documentation that directly addresses citation behavior, especially OpenAI’s citation-formatting guide and Deep Research guidance ^[1][7]. - The strongest Anthropic evidence in this set is vendor-primary documentation on model positioning and workflow components, including the model intro, Files API, prompt caching, and extended-thinking skill behavior ^[4][2][3][8]. Limitations / uncertainty - The evidence provided here is limited to vendor documentation snippets rather than full pages, and several snippets are partial, so claims beyond the visible text would be unsafe ^{[1][2][3][4][5][6][7][8]}. - Because the supplied materials do not include a model-specific page, benchmark, or technical documentation for GPT-5.5 Spud, an apples-to-apples model comparison is not possible from this evidence alone ^[1][7]. - The supplied Anthropic excerpts document reasoning-related mechanisms, but they do not establish, in the visible text, whether internal thinking artifacts are exposed to end users or mapped back to sources ^[3][8]. Summary The supported conclusion is limited but clear: in the supplied evidence, OpenAI is more explicit about end-user evidence provenance through citation formatting guidance and a requirement for visible, clickable inline citations in Deep Research outputs ^[1][7]. Anthropic is more explicit here about Claude Opus 4.7’s capability positioning and about workflow mechanics such as files, prompt caching, and extended thinking, but the supplied excerpts do not show an equally explicit public provenance standard for citations, scratchpads, or traceability ^[4][2][3][8]. A definitive Claude Opus 4.7 vs GPT-5.5 Spud verdict on research provenance is therefore not supported. Insufficient evidence ^[1][7].