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Head-to-head comparison

Claude Fable 5 vs GLM 5.3

Claude Fable 5 (Anthropic) and GLM 5.3 (Z.ai) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 19 August 2026

As of 19 August 2026, Claude Fable 5 holds the stronger ModelCap Index position (#1 vs #7); and GLM 5.3 is 11.4× cheaper per output token ($4.40/1M vs $50.00/1M).

Which should you choose?

Choose Claude Fable 5 if…

  • you want the stronger overall ModelCap Index position — #1 against #7 (84.3 vs 78.4 points).
  • you want provider choice — 5 listed API providers against 1.
  • Artificial Analysis Intelligence Index is your yardstick — 62.1 against 59.5.

Choose GLM 5.3 if…

  • API cost matters — $4.40/1M output tokens against $50.00/1M, about 11.4× cheaper.
  • your workload is prompt-heavy — input tokens cost $1.40/1M against $10.00/1M.
  • you want the more recently listed model — GLM 5.3 was listed 18 August 2026, Claude Fable 5 9 June 2026.

Claude Fable 5 vs GLM 5.3: specs, pricing and context

Specification comparison of Claude Fable 5 and GLM 5.3
FieldClaude Fable 5AnthropicGLM 5.3Z.ai
ModelCap Index position#1#7
Index score84.378.4
EvidenceMeasuredMeasured
Input price / 1M tokens$10.00$1.40
Output price / 1M tokens$50.00$4.40
Context window1M tokens1M tokens
Max output tokens128K131K
API providers listed51
Weight accessAPI onlyAPI only
Input modalitiesText, Image, FileText
First listed9 June 202618 August 2026
PublisherAnthropicZ.ai

Evidence: 7 public benchmark observations across 7 boards · 1 public benchmark observation across 1 board. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Claude Fable 5 vs GLM 5.3

Public benchmark boards where Claude Fable 5 or GLM 5.3 has a published result
BoardClaude Fable 5GLM 5.3Leads
Arena codingArena (LMArena)15541546–1563—Only one result
LMArena AgentLMArena12.0%9.4%–14.6%High—Only one result
ARC-AGI-2ARC Prize Foundation89.2%Max—Only one result
Terminal-Bench 2.1 Terminus 2Terminal-Bench80.4High—Only one result
WildClawBench OpenClawWildClawBench62.0—Only one result
Artificial Analysis Intelligence IndexArtificial Analysis62.1intelligence-index59.5intelligence-indexClaude Fable 5

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Claude Fable 5 vs GLM 5.3: common questions

Is Claude Fable 5 better than GLM 5.3?

Claude Fable 5 ranks higher on the ModelCap Index as of 19 August 2026: #1 against #7. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it.

Is Claude Fable 5 cheaper than GLM 5.3?

GLM 5.3 is cheaper on output tokens: $4.40/1M against $50.00/1M. Input tokens are $10.00/1M for Claude Fable 5 and $1.40/1M for GLM 5.3. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, Claude Fable 5 or GLM 5.3?

Both publish a 1M-token context window.

Which is better for coding, Claude Fable 5 or GLM 5.3?

The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.

Are Claude Fable 5 and GLM 5.3 open-weight models?

Claude Fable 5: API only. GLM 5.3: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run Claude Fable 5 and GLM 5.3?

ModelCap currently lists 5 API providers for Claude Fable 5 and 1 for GLM 5.3, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Claude Fable 5 vs GLM 5.3 comparison?

Every figure comes from the sealed ModelCap dataset published 19 August 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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