Model Comparison
Claude Sonnet 5.5 vs GPT-6.1 Terra
Claude Sonnet 5.5 (max effort) leads GPT-6.1 Terra (max) by 606 Elo, and their 95% ranges sit 519 Elo apart. Among 84 models, each ranked by its best configuration, Claude Sonnet 5.5 is #2 and GPT-6.1 Terra is #23. Cost per script: $1.38 for Claude Sonnet 5.5 (max effort) and $0.079 for GPT-6.1 Terra (max).
Last updated , from board data generated at 20:15 UTC.
Picks and Verdict
PickClaude Sonnet 5.5
Claude Sonnet 5.5 (xhigh)
Pick Claude Sonnet 5.5 (xhigh) for scripts you'll publish, 379 Elo above Terra's best with separate ranges, at $0.302 a script and 3.1 minutes.
PickGPT-6.1 Terra
GPT-6.1 Terra (low)
Pick GPT-6.1 Terra (low) for cheap drafts at $0.027 a script, since it ranks above Sonnet at low and medium with separate ranges and costs less than half as much.
At the top, Claude Sonnet 5.5 is in another league, but lower down GPT-6.1 Terra holds its own. Claude Sonnet 5.5 is the #2 model of 84 and GPT-6.1 Terra the #23 model, each ranked by its best setting. Claude Sonnet 5.5 (max effort) sits 606 Elo above GPT-6.1 Terra (max), with 95% ranges 519 Elo apart, and Sonnet at xhigh is still 379 Elo ahead for $0.302 a script. Sonnet's ladder is steep, though, 754 Elo from low to max, and that's where Terra catches up. Sonnet at high overlaps Terra at low for more than three times the price, and Sonnet at low and medium cost more than Terra at low and rank below it with separate ranges. Terra's five levels sit within 25 Elo of each other with overlapping ranges, so low is the one I would use, at about half a minute a script. Sonnet at max takes 14.3 minutes and costs $1.38. The top settings split most on Continuity & Emotion, 7.0 points to Sonnet, and Tone & Voice Match, 6.5. Terra's edge is slop: at low it scores 3.4 points better than Sonnet at high. I'd run Sonnet at xhigh for scripts I publish and Terra at low when the budget is a few cents a script.
Disclosure: Claude Sonnet 5.5 and GPT-6.1 Terra each come from the same lab as one of the judges (Claude Opus 5.5 and GPT-6.1 Sol). Neither is scored by its own lab alone (how the panel works). The judge analysis measures how much each judge favors its own lab.
How to Read the Writing Score, Writing Elo and 95% Ranges
Writing Score and Writing Elo. The Writing Score (0 to 100) is the weighted average of the nine metric scores: seven from the judges, Length Adherence from code and the Slop Score half from each. The Writing Elo is a rating from pairwise comparisons: on each script, each configuration's average across its drafts is compared with every other configuration's, and gaps within the draft-to-draft variation count as draws. Elo rewards winning often, so the two can put configurations in a different order.
Elo ranges. Each 95% range shows how far a configuration's Elo could move if the drafts had come out slightly differently. It comes from resampling every configuration's recorded draft scores on each reference script and ranking again. Comparing two separate ranges does not test the Elo gap between them: ranges far apart are strong evidence for the order, and overlapping ranges do not mean a tie. The reference scripts stay fixed, so the ranges say nothing about new scripts. The methodology page has the full description.
All Thinking Levels of Both Models
Every ranked configuration of Claude Sonnet 5.5 and GPT-6.1 Terra, scored on the same 10 scripts by the same four judges.
- Each row is one configuration: the model at one thinking level. The dot is its Writing Elo, a rating from pairwise comparisons of the scores on each script, and the bar is its 95% range: how far that Elo could move if the drafts had come out slightly differently.
- Each bar describes one configuration. Overlap alone does not establish a tie or decide their order. Comparing these ranges does not directly test the difference between a pair.
- The table under the chart lists the same configurations in the same order and adds the Writing Score (the 0 to 100 consensus of the judges and code), cost, time and configuration rank (the place among all configurations on the board).
Shaded rows are the configurations chosen for the metric comparison below.
| Configuration | Writing Elo | 95% Range | Writing Score | Cost / Script | Time / Script | Configuration Rank |
|---|---|---|---|---|---|---|
| Claude Sonnet 5.5 (max effort) | 2529 | 2478 to 2585 | 84.6 | $1.38 | 14.3 min | #3 |
| Claude Sonnet 5.5 (xhigh) | 2302 | 2256 to 2337 | 83.2 | $0.302 | 3.1 min | #10 |
| Claude Sonnet 5.5 (high) | 2002 | 1953 to 2043 | 81.0 | $0.092 | 1.0 min | #30 |
| GPT-6.1 Terra (max) | 1923 | 1884 to 1959 | 80.3 | $0.079 | 1.8 min | #43 |
| GPT-6.1 Terra (high) | 1922 | 1881 to 1958 | 80.3 | $0.027 | 0.5 min | #44 |
| GPT-6.1 Terra (low) | 1920 | 1879 to 1961 | 80.2 | $0.027 | 0.5 min | #46 |
| GPT-6.1 Terra (xhigh) | 1906 | 1869 to 1944 | 80.1 | $0.028 | 0.5 min | #48 |
| GPT-6.1 Terra (medium) | 1898 | 1852 to 1942 | 79.9 | $0.027 | 0.5 min | #49 |
| Claude Sonnet 5.5 (medium) | 1820 | 1782 to 1857 | 79.4 | $0.065 | 0.6 min | #56 |
| Claude Sonnet 5.5 (low) | 1775 | 1733 to 1806 | 78.9 | $0.061 | 0.7 min | #59 |
Cost is one script at the API list price of the route used, uncached and without judging. Time is the average for one accepted script, retries included.
Computed Findings Across Thinking Levels
Each finding is computed from the configurations above. The 95% ranges describe individual configurations; overlap alone establishes neither a tie nor an order for a pair.
- Best Configurations Head to Head. Claude Sonnet 5.5 (max effort) leads GPT-6.1 Terra (max) by 606 Elo, and their 95% ranges do not overlap (2478 to 2585 against 1884 to 1959), which is strong evidence for that order.
- Lowest Thinking Levels Head to Head. At their lowest thinking levels, GPT-6.1 Terra (low) at Elo 1920 and $0.027 per script leads Claude Sonnet 5.5 (low) at Elo 1775 and $0.061 per script by 145 Elo. Their 95% ranges do not overlap.
- Same Level Name, Side by Side. Across the level names both models use, Claude Sonnet 5.5 leads at high, xhigh, and max; GPT-6.1 Terra leads at low and medium. The 95% ranges do not overlap at low, xhigh, and max. Level names come from each provider, so the same name does not promise the same reasoning budget.
- Cheapest Claude Sonnet 5.5 Configuration Above GPT-6.1 Terra's Best. The cheapest Claude Sonnet 5.5 configuration with a higher Writing Elo than GPT-6.1 Terra (max), at Elo 1923 and $0.079 per script, is Claude Sonnet 5.5 (high), at Elo 2002 and $0.092 per script. Their 95% ranges overlap. The two cost about the same per script.
- Lowest to Highest Thinking Level. Claude Sonnet 5.5 moves +754 Elo from low to max effort, at about 23 times the cost per script. GPT-6.1 Terra moves +3 Elo from low to max, at about 2.9 times the cost per script.
Writing Elo at Each Shared Level Name
| Level | Claude Sonnet 5.5 | GPT-6.1 Terra | Gap | 95% Ranges |
|---|---|---|---|---|
| low | 1775 | 1920 | -145 | Separate |
| medium | 1820 | 1898 | -78 | Overlap |
| high | 2002 | 1922 | +80 | Overlap |
| xhigh | 2302 | 1906 | +396 | Separate |
| max | 2529 | 1923 | +606 | Separate |
Gap is Claude Sonnet 5.5 minus GPT-6.1 Terra at the same level name, using each model's highest-rated configuration at that level.
Two Chosen Configurations Compared
Pick one configuration of each model to compare their metric scores, consistency across drafts and per-script scores. Each menu starts on the model's best configuration.
Scores by Metric
Claude Sonnet 5.5 (max effort) scores higher on eight of the nine metrics and GPT-6.1 Terra (max) on one. Weighted by each metric's share of the Writing Score, Tone & Voice Match does the most to put Claude Sonnet 5.5 (max effort) ahead, with a 6.5-point lead on that metric. The weight beside each metric is its share of the Writing Score.
Consistency Across Drafts
| Claude Sonnet 5.5 (max effort) | GPT-6.1 Terra (max) | |
|---|---|---|
| Score spread across drafts (±) | 1.22 | 1.68 |
| Lowest script score | 83.0 Script 10 | 77.9 Script 10 |
| Highest script score | 86.7 Script 9 | 83.2 Script 9 |
| Range across scripts | 3.7 | 5.3 |
Spread is how much the Writing Score moves between a configuration's drafts, and lower is steadier. Green marks the better number in each row.
Scores by Script
Writing Score on each reference script. Gap is Claude Sonnet 5.5 (max effort) minus GPT-6.1 Terra (max), and the higher score is in bold.
| Script | Claude Sonnet 5.5 (max effort) | GPT-6.1 Terra (max) | Gap |
|---|---|---|---|
| Script 1 opinion / warning explainer | 84.2 | 80.2 | +4.0 |
| Script 2 news-analysis / skeptical explainer | 84.8 | 80.7 | +4.1 |
| Script 3 personal roadmap / opinion | 84.0 | 80.4 | +3.6 |
| Script 4 short explainer | 85.0 | 79.6 | +5.4 |
| Script 5 news-analysis / opinion explainer | 84.8 | 80.1 | +4.7 |
| Script 6 founder announcement / personal origin story | 84.6 | 82.2 | +2.4 |
| Script 7 personal technical walkthrough / agentic workflow case study | 85.0 | 79.9 | +5.1 |
| Script 8 product release announcement / personal observation | 83.9 | 79.1 | +4.8 |
| Script 9 career guide / hiring analysis | 86.7 | 83.2 | +3.5 |
| Script 10 engineering process walkthrough / presentation adaptation | 83.0 | 77.9 | +5.1 |
Scorecards and Thinking Pages
Each configuration name in the table above opens its own scorecard.
Compare With Another Model
Pick a second model. A pair with its own written match-up opens that page, and any other pair opens in the comparison tool.
Nearby Match-Ups by Best Writing Elo
Every configuration wrote five drafts for each of the same 10 briefs, from the same prompt. Generation was closed-book, with the prompt as the only source and no web search or other tools. Each judge scores every draft once: Claude Opus 5.5 at medium effort through the Claude Code subscription, GPT-6.1 Sol at medium reasoning through the Codex CLI, GLM 5.3 Flash through OpenRouter, and Jev 1.13, a typed judge from TypeSafe that answers each metric as a multiple-choice question. The channel's finished script is their reference for the voice, and it gets no score on the board itself.
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