cfahlgren1/web-fetch-harness-traces
Native web fetch harness traces Separate, lightly sanitized native JSONL traces comparing URL-fetch behavior in Claude Code and Codex CLI against: https://huggingface.co/datasets/nyu-mll/glue Captured on 2026-09-15. No shell HTTP client, browser automation, or MCP fetcher was used. Files data/claude-code.jsonl: Claude Code's stream-json events. data/codex.jsonl: Codex's persisted native rollout JSONL. Both traces are exposed together in the default subset and… See the full description on the dataset page: https://huggingface.co/datasets/cfahlgren1/web-fetch-harness-traces.
Native web fetch harness traces
Separate, lightly sanitized native JSONL traces comparing URL-fetch behavior in Claude Code and Codex CLI against:
https://huggingface.co/datasets/nyu-mll/glue
Captured on 2026-09-15. No shell HTTP client, browser automation, or MCP fetcher was used.
Files
data/claude-code.jsonl: Claude Code'sstream-jsonevents.data/codex.jsonl: Codex's persisted native rollout JSONL.
Both traces are exposed together in the default subset and train split.
The files retain each harness's native event envelopes, ordering, identifiers, usage metadata, tool calls, tool results, and final responses. Codex developer and injected harness context, base instructions, turn context, world state, skill warnings, local working-directory metadata, and reasoning records were removed. No common schema or normalized trace wrapper was introduced.
Interpretation
- Claude Code asked
WebFetchfor the converted page verbatim and copied the returned tool result byte-for-byte as its final response. TheWebFetchhelper still returned a prompt-conditioned summary rather than the source document. - Codex's Responses API
web_searchURL-open action exposed a transformed, line-numbered representation of the page rather than raw HTML. Its CLI event stream kept the fetched document opaque and exposed the model's report about it. These are observations from the named versions and configuration at capture time, not permanent API contracts.
