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GLM-5.3 vs Claude Fable 5
Claude Fable 5 scores higher than GLM-5.3 on all 6 public leaderboards that rate both. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, GLM-5.3 is at 42.4 and Claude Fable 5 at 85.1 (out of 100).
Scores as published by each board; table composed September 28, 2026.
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Leaderboard by leaderboard
| Board | GLM-5.3 | Claude Fable 5 | Higher |
|---|---|---|---|
| LMArena Elo (community votes) | 1,619.1 | 1,627 | Claude Fable 5 |
| LiveBench global average (0-100) | 76.1 | 83 | Claude Fable 5 |
| SimpleBench AVG@5 % (private set) | 66.2 | 81.9 | Claude Fable 5 |
| LLM Stats LLM Stats Score · composite (0-100), their rendered top 15 | 52.1 | 54 | Claude Fable 5 |
| Vals AI Vals Index accuracy % · weighted finance + coding tasks | 57 | 66 | Claude Fable 5 |
| Artificial Analysis intelligence index · measured runs only | 44.8 | 49.6 | Claude Fable 5 |
Raw scores are each board's own scale, so compare within a row, not across rows. Full table: the bench index.
For coding
On the ArtificialWatch coding index, GLM-5.3 is at 48.3 (#16 of 31) and Claude Fable 5 at 100 (#1). Claude Fable 5 scores higher on all 3 coding boards that rate both.
| Coding board | GLM-5.3 | Claude Fable 5 |
|---|---|---|
| LMArena · Coding | 1,522 | 1,550.7 |
| LiveBench · Coding | 69.9 | 74.1 |
| Vals Vibe Code Bench | 78.1 | 90.4 |
GLM-5.3 at a glance
- Developer
- Zhipu AI
- Status
- Live since August 14, 2026
- API price
- $1.40 input / $4.40 output per 1M tokens · Z.AI, glm-5.3
- Context window
- 1M tokens
Live - same 743B base as 5.2, every gain from post-training · tops CyberGym · open weights on Hugging Face (zai-org/GLM-5.3, 141 safetensors files, public when we read it Sep 25; repo created Aug 25).
GLM-5.3 tops CyberGym and trails the frontier on exploitation — and we missed it because the sweep had no eyes on models.dev
2026-08-14 · Z.ai shipped GLM-5.3 today, and we did not catch it. The entry was armed and the pattern was right — the sweep simply had no source that carried the id. That is now fixed, and the fix is the more useful half of this post.
Claude Fable 5 at a glance
- Developer
- Anthropic
- Status
- Live since July 1, 2026
- API price
- $10 input / $50 output per 1M tokens · Anthropic, claude-fable-5
- Context window
- 1M tokens
Returned Jul 1.
GLM-5.3 vs Claude Fable 5: quick answers
Which is better, GLM-5.3 or Claude Fable 5?
It depends on what you measure. Claude Fable 5 scores higher than GLM-5.3 on all 6 public leaderboards that rate both. Claude Fable 5's widest lead is on LiveBench. On the ArtificialWatch Index, which takes the median of each model's percentile across the boards that score it, GLM-5.3 is at 42.4 and Claude Fable 5 at 85.1 (out of 100).
Which is newer, GLM-5.3 or Claude Fable 5?
GLM-5.3. It went live on August 14, 2026, 44 days after Claude Fable 5 (July 1, 2026).
Which is cheaper, GLM-5.3 or Claude Fable 5?
GLM-5.3 is cheaper on both input and output. On each vendor's own API, GLM-5.3 is $1.40 input / $4.40 output per million tokens and Claude Fable 5 is $10 input / $50 output per million tokens. Prices as published in the models.dev catalog, as of 2026-09-27.
Which has the bigger context window, GLM-5.3 or Claude Fable 5?
Neither. Both take 1M tokens.
How do GLM-5.3 and Claude Fable 5 compare for coding?
On the ArtificialWatch coding index, GLM-5.3 is at 48.3 (#16 of 31) and Claude Fable 5 at 100 (#1). Claude Fable 5 scores higher on all 3 coding boards that rate both.
Who makes GLM-5.3 and Claude Fable 5?
GLM-5.3 is from Zhipu AI; Claude Fable 5 is from Anthropic.
Where do these numbers come from?
Each score is the leaderboard's own published figure, read by ArtificialWatch (table composed September 28, 2026). Boards measure different things, so raw scores are only comparable within a row.
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