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Claude Fable 5.1 vs Kimi K2.7 Code

Claude Fable 5.1 is served by invitation. Its figures below are the live rates, but calls need a workspace grant first; ask us for access before you build on this comparison.

vs

Which one, when

Pick claude-fable-5-1 when the job needs room: its 1000000-token context is nearly 4x that of kimi-k2.7-code, its 128000-token max output is about 4x larger, and it carries an explicit thinking flag on top of chat, code, tools and reasoning. Pick kimi-k2.7-code when cost or video input drives the decision, since it takes text, image and video and bills $0.95 input and $4 output against $10 and $50 - roughly 10.5x and 12.5x cheaper - with cache reads at $0.19 versus $0.25. Both are text-out, tool-capable models whose thinking cannot be disabled.

Benchmarks

Above averageNo peer higherClaude Fable 5.17 / 77 / 7Kimi K2.7 Code1 / 50 / 5
Claude Fable 5.1 Kimi K2.7 Code other models measured peer average no peer scored higher
MLS-Bench-Lite
N/A
35.1%
OSWorld 2.0 partial
77.9%
N/A
GDPval-AA v2 Elo · 1711-1853 per Anthropic · 2026-09-05
no peer scored higher 1853
N/A
Humanity's Last Exam no tools
no peer scored higher 60.9%
N/A
MCP-Atlas
N/A
76%

Vendor-published: Alibaba (Qwen) Anthropic DeepSeek Google MiniMax Moonshot OpenAI Z.ai

Pricing

Claude Fable 5.1 Kimi K2.7 Code Δ
Input / 1M tokens $10 $0.95 11×
Output / 1M tokens $50 $4 13×
Cache read / 1M tokens $0.25 $0.19 1.3×
Cache write 1.25x (5m) / 2x (1h) - -

Rates from the live catalog at build time; each model page carries the current card.

Where they sit - input price per 1M tokens across all 67 chat models on this billing unit (log scale)

$0.05 · Qwen3 VL Flash $30 · GPT-5.4 Pro

Capabilities

Claude Fable 5.1 Kimi K2.7 Code
Tool use yes yes
Thinking control always on always on
Structured output yes -
Prompt caching explicit (you mark the prefix) implicit (automatic)
Cache lifetime 5m default, 1h option not published
Minimum cached prefix 1024 tokens not published

Specs

Claude Fable 5.1 Kimi K2.7 Code
Input modalities text image text image video
Output modalities text text
Released 2026-09-01 2026-06
Knowledge cutoff 2026-06 -
Context window 1M 256K
Max output 128K 33K
Thinking parameter output_config.effort (thinking is adaptive-only and always on)
  • thinking.type
  • thinking.keep
Accepted values
effort
  • low
  • medium
  • high
  • xhigh
  • max
type
  • accepts only enabled
keep
  • accepts only all
Default

thinking always on (adaptive)

effort
  • high
thinking on with Preserved Thinking on

Specs are transcribed from each vendor’s documentation; a row a vendor does not publish is left out rather than inferred. Full sources: Claude Fable 5.1 · Kimi K2.7 Code

Switch between them with one line

Both ids are in every tab below - the highlighted pair of lines is the only edit. Same endpoint, same key, same request shape.

from openai import OpenAI

client = OpenAI(
    base_url="https://synthorai.io/v1",
    api_key="sk-syn-...",
)

resp = client.chat.completions.create(
    model="claude-fable-5-1",
    # model="kimi-k2.7-code",  # uncomment this line, comment the one above
    messages=[{"role": "user", "content": "Summarize this diff"}],
    reasoning_effort="medium",
)
print(resp.choices[0].message.content)

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FAQ

Which is cheaper, Claude Fable 5.1 or Kimi K2.7 Code?

Kimi K2.7 Code is cheaper on input / 1m tokens ($0.95 vs $10, 11× apart). Other rows may point the other way - the table above carries the full card, and real cost depends on your mix.

Can I A/B test Claude Fable 5.1 against Kimi K2.7 Code without two integrations?

Yes. Both are served through the same OpenAI-compatible endpoint with one API key - switching is a one-line model-string change, so you can route a fraction of traffic to each and compare bills directly.

Do Claude Fable 5.1 and Kimi K2.7 Code support prompt caching?

Yes - both bill cached reads below their input rate, so warm-prefix workloads cost less than the list rates suggest. The exact cache-read rows are in the pricing table above.

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