Model Comparison
GLM-5.3 vs Claude Opus 4.8
GLM-5.3 (max) leads Claude Opus 4.8 (max effort) by 207 Elo, and their 95% ranges sit 136 Elo apart. Among 78 models, each ranked by its best configuration, GLM-5.3 is #7 and Claude Opus 4.8 is #15. Cost per script: $0.240 for GLM-5.3 (max) and $1.23 for Claude Opus 4.8 (max effort).
Last updated , from board data generated at 01:13 UTC.
Picks and Verdict
PickGLM-5.3
GLM-5.3 (max)
Pick GLM-5.3 (max) as the main writer, since it rates above both Claude Opus 4.8 settings at about a fifth of the max effort price, $0.240 a script.
PickClaude Opus 4.8
Claude Opus 4.8 (high)
Pick Claude Opus 4.8 (high) when turnaround matters most, since it returns a script in 1.4 minutes for $0.193, the fastest and cheapest setting on this page.
Claude Opus 4.8 (max effort) asks about five times GLM-5.3's price for a lower-rated script. GLM-5.3 is the #7 model of 78 at 2220 Elo and Claude Opus 4.8 the #15 model at 2013, each ranked by its best setting. That's 207 points, and their 95% ranges don't touch, which is strong evidence for GLM. Time goes the same way: about six minutes a script for GLM against nearly ten. Claude Opus 4.8's two settings show what the extra effort buys. Going from high to max adds 145 Elo for about 6.4 times the cost, and it still leaves the model well behind GLM-5.3. Claude Opus 4.8 (high) is the cheapest and fastest row on this page, $0.193 and 1.4 minutes a script, but it lands 352 Elo under GLM. In fairness, at max it matches GLM on Visual Cue Quality and edges it on length. Its drafts swing more from one to the next, though. For me GLM-5.3 is the easy call here, at $0.240 a script against $1.23.
Disclosure: GLM-5.3 and Claude Opus 4.8 each come from the same lab as one of the judges (GLM 5.3 Flash and Claude Opus 5.5). 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 GLM-5.3 and Claude Opus 4.8, 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.
- When two bars overlap, the board cannot order those two configurations. Bars far apart are strong evidence for the order.
- 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 | Reasoning Tokens | Configuration Rank |
|---|---|---|---|---|---|---|---|
| GLM-5.3 (max) | 2220 | 2183 to 2259 | 82.4 | $0.240 | 6.1 min | 46,444 | #15 |
| Claude Opus 4.8 (max effort) | 2013 | 1977 to 2047 | 80.7 | $1.23 | 9.8 min | N/A | #30 |
| Claude Opus 4.8 (high) | 1868 | 1827 to 1905 | 79.3 | $0.193 | 1.4 min | N/A | #44 |
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. N/A under Reasoning Tokens means the board has no separate reasoning count for that route.
Computed Findings Across Thinking Levels
Each finding is computed from the configurations above. Where two 95% ranges overlap, the board cannot order those two configurations.
- Best Configurations Head to Head. GLM-5.3 (max) leads Claude Opus 4.8 (max effort) by 207 Elo, and their 95% ranges do not overlap (2183 to 2259 against 1977 to 2047), which is strong evidence for that order.
- Every GLM-5.3 Configuration Ranks Higher. GLM-5.3 (max), the only GLM-5.3 configuration on the board, ranks above both Claude Opus 4.8 configurations, including Claude Opus 4.8 (max effort) at Elo 2013.
- Same Level Name, Side by Side. At max, the one level name both models use, GLM-5.3 has the higher Writing Elo: 2220 against 2013. Their 95% ranges do not overlap there. Level names come from each provider, so the same name does not promise the same reasoning budget.
- Lowest to Highest Thinking Level. Claude Opus 4.8 moves +145 Elo from high to max effort, at about 6.4 times the cost per script.
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
GLM-5.3 (max) scores higher on seven of the nine metrics and Claude Opus 4.8 (max effort) on one, with one tie. Weighted by each metric's share of the Writing Score, Tone & Voice Match does the most to put GLM-5.3 (max) ahead, with a 3.0-point lead on that metric. The weight beside each metric is its share of the Writing Score.
Consistency Across Drafts
| GLM-5.3 (max) | Claude Opus 4.8 (max effort) | |
|---|---|---|
| Score spread across drafts (±) | 1.39 | 2.02 |
| Lowest script score | 80.5 Script 10 | 77.5 Script 4 |
| Highest script score | 84.1 Script 7 | 83.1 Script 6 |
| Range across scripts | 3.6 | 5.6 |
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 GLM-5.3 (max) minus Claude Opus 4.8 (max effort), and the higher score is in bold.
| Script | GLM-5.3 (max) | Claude Opus 4.8 (max effort) | Gap |
|---|---|---|---|
| Script 1 opinion / warning explainer | 82.1 | 80.2 | +1.9 |
| Script 2 news-analysis / skeptical explainer | 82.5 | 80.6 | +1.9 |
| Script 3 personal roadmap / opinion | 81.5 | 79.3 | +2.2 |
| Script 4 short explainer | 81.0 | 77.5 | +3.5 |
| Script 5 news-analysis / opinion explainer | 82.5 | 80.3 | +2.2 |
| Script 6 founder announcement / personal origin story | 82.9 | 83.1 | -0.2 |
| Script 7 personal technical walkthrough / agentic workflow case study | 84.1 | 82.5 | +1.6 |
| Script 8 product release announcement / personal observation | 82.7 | 82.5 | +0.2 |
| Script 9 career guide / hiring analysis | 84.0 | 82.0 | +2.0 |
| Script 10 engineering process walkthrough / presentation adaptation | 80.5 | 78.9 | +1.6 |
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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