activeCodingAgents

FrontierCode 2.0

Metric: Mean@5 score (higher is better)Introduced: 2026

Cognition's FrontierCode 2.0 is a rebuilt 132-task agentic coding suite (FrontierCode 1.1 had 150 tasks) with updated scope grading. Tasks come from real open-source pull requests. The official score is a mean@5 composite of functional and rubric criteria measuring whether an agent produces a mergeable patch. Scores are not comparable with FrontierCode 1.1 Main or Extended (frontiercode-main / frontiercode-extended) and must not be restamped onto those slugs.

Models ranked

1

tracked on this benchmark

Score band

49.1 – 49.1

best → lowest tracked

Snapshot trend

—

need ≥2 snapshots

Leaderboard

Tracked models ranked by Mean@5 score (higher is better).

Compare candidates
#Model variant and provenanceScore
1

Configuration: claude-fable-5-2 (XHigh)

Version: FrontierCode 2.0Harness: Claude Code (Cognition official evaluation)Evaluator: CognitionObserved: Nov 9, 2026Confidence: confirmedSource

Notes: Cognition official FrontierCode 2.0 board (https://cognition.com/frontiercode, retrieved 2026-11-09): JSON-LD ListItem position 1, name 'Claude Fable 5.2', description 'Score 49.1%'. The Anthropic system card §8.4 confirms Cognition ran the evaluation (official eval, no changes), 132-task rebuilt suite (FrontierCode 1.1 had 150) with updated scope grading — scores are not comparable to frontiercode-main (1.1). Mean@5 composite. Effort peak is xhigh 49.1%; other Cognition/card efforts: low 34.2, medium 37.6, high 45.3, max 45.7 (max includes 22/660 timed-out attempts still graded; if timed out as zero, 44.4%). Claude models run in Claude Code. Highest-scoring published effort selected. This is an owner-board row on a NEW slug; it must not be written onto frontiercode-main. A /best/agents key move from FrontierCode 1.1 Main to FrontierCode 2.0 would put Fable 5.2 first at 49.1 and is a separate FE PR, not this packet.

49.1

How to read this benchmark

This benchmark scores models where higher is better. Use scores for directional filtering and shortlisting, not universal quality ranking; then validate pricing, context window, provider availability, and fit for your workload.

Trust this score when

  • There is a fresh timestamped snapshot (or multiple snapshots) for this benchmark.
  • The model list covers the same version family you can actually deploy today.
  • Top candidates overlap with your required routing and feature requirements.

Be cautious when

  • There is only one benchmark snapshot or the dataset appears stale.
  • The benchmark metric direction is opposite of your decision objective.
  • The score difference between options is narrow and likely within implementation variance.

Related benchmarks

Last reviewed: Nov 9, 2026

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