Pick Claude Fable 5.1 for terminal-bench-science agentic research (52.6%, more than double fable 5's 24.7%) or cursorbench 3.2 agentic coding (73.4%). Pick Palmyra X6 for enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents or writer says its harness upgrades cut agent-workflow token costs by roughly 52% and improve speed by roughly 48% (writer's own figures). On a tight budget at scale, Palmyra X6 is the value pick.
Claude Fable 5.1 (Anthropic) and Palmyra X6 (Writer) are two of the models people most often weigh against each other in 2026. Claude Fable 5.1 is anthropic's September 1, 2026 update to its Fable line for coding and knowledge work, keeping the 1M-token context of Fable 5 while cutting cache-read costs and roughly doubling agentic-research benchmark scores. Palmyra X6 is writer's enterprise agentic flagship - a GLM-5.2-based model with harness upgrades Writer says cut agent token costs by roughly half. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences
Context window: Claude Fable 5.1 holds 7.8× more — 1M tokens (~1,500 pages) vs 128K (~192 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
Recency: Claude Fable 5.1 is the newer model by about 19 days (released September 1, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Fable 5.1
Palmyra X6
Provider
Anthropic (US)
Writer (US)
Released
September 1, 2026
August 13, 2026
Context window
1M tokens (~1,500 pages)
128K (~192 pages)
Price (in/out)
$10/$50 per 1M tokens
Not published
Open weight?
No — API only
No — API only
Modalities
text, image
text, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Terminal-Bench-Science agentic research (52.6%, more than double Fable 5's 24.7%): Claude Fable 5.1 — Palmyra X6 is comparatively weak here — not independently benchmarked on general leaderboards like SWE-bench or Artificial Analysis
CursorBench 3.2 agentic coding (73.4%): Claude Fable 5.1 — Anthropic's September 1, 2026 update to its Fable line for coding and knowledge work, keeping the 1M-token context of Fable 5 while cutting cache-read costs and roughly doubling agentic-research benchmark scores — and it carries the larger 1M tokens context.
Cache-read pricing cut to a quarter of other Claude models: Claude Fable 5.1 — Anthropic's September 1, 2026 update to its Fable line for coding and knowledge work, keeping the 1M-token context of Fable 5 while cutting cache-read costs and roughly doubling agentic-research benchmark scores — and it is the newer of the two.
Enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents: Palmyra X6 — Palmyra X6 lists enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents among its strengths; Claude Fable 5.1 does not.
Writer says its harness upgrades cut agent-workflow token costs by roughly 52% and improve speed by roughly 48% (Writer's own figures): Palmyra X6 — Palmyra X6 lists writer says its harness upgrades cut agent-workflow token costs by roughly 52% and improve speed by roughly 48% (Writer's own figures) among its strengths; Claude Fable 5.1 does not.
A post-trained variant built on Z.ai's open-weight GLM-5.2, tuned specifically for business agent use: Palmyra X6 — Claude Fable 5.1 is comparatively weak here — restricted Mythos 5.1 variant outscores it on some benchmarks due to lighter safeguards (Terminal-Bench 4.0: 60.9% vs 55.8%)
Lowest cost at scale: Palmyra X6 — Its weights are open, so at volume you pay for your own hardware instead of Claude Fable 5.1's $10/$50 per 1M tokens.
Largest single-prompt input: Claude Fable 5.1 — Its 1M tokens window is about 7.8× larger than Palmyra X6's 128K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Palmyra X6 — At Not published it undercuts Claude Fable 5.1, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Claude Fable 5.1 — Larger 1M tokens window fits more in one prompt.
Anyone whose priority is terminal-bench-science agentic research (52.6%, more than double fable 5's 24.7%): Claude Fable 5.1 — It is specifically built for that.
Anyone whose priority is enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents: Palmyra X6 — That is its strongest area.
Claude Fable 5.1: where it fits
Anthropic's September 1, 2026 update to its Fable line for coding and knowledge work, keeping the 1M-token context of Fable 5 while cutting cache-read costs and roughly doubling agentic-research benchmark scores. Released September 1, 2026 by Anthropic, it is built for terminal-Bench-Science agentic research (52.6%, more than double Fable 5's 24.7%), cursorBench 3.2 agentic coding (73.4%), cache-read pricing cut to a quarter of other Claude models, and long, multistep, document-heavy professional work with 1M-token context.
Its trade-offs are real: anthropic has not published an official SWE-bench Verified score for this model, restricted Mythos 5.1 variant outscores it on some benchmarks due to lighter safeguards (Terminal-Bench 4.0: 60.9% vs 55.8%), and closed weights, no self-hosting option. At $10 in / $50 out per million tokens, it sits in the premium price band.
Palmyra X6: where it fits
Writer's enterprise agentic flagship - a GLM-5.2-based model with harness upgrades Writer says cut agent token costs by roughly half. Released August 13, 2026 by Writer, it is built for enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents, writer says its harness upgrades cut agent-workflow token costs by roughly 52% and improve speed by roughly 48% (Writer's own figures), and a post-trained variant built on Z.ai's open-weight GLM-5.2, tuned specifically for business agent use.
Its trade-offs: no public per-token API price - sold through Writer's enterprise platform, not a self-serve API, not independently benchmarked on general leaderboards like SWE-bench or Artificial Analysis, and built for a narrower enterprise-agent use case rather than general-purpose chat.
The bottom line for this matchup
Claude Fable 5.1 and Palmyra X6 overlap enough that the right pick depends on your specific job. Palmyra X6 costs less per token; Claude Fable 5.1 holds the larger context; and each leads in its own area — Claude Fable 5.1 for terminal-bench-science agentic research (52.6%, more than double fable 5's 24.7%), Palmyra X6 for enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents. Rather than crowning one, run the same hard task through both once and let the results decide.
Frequently asked questions
Is Claude Fable 5.1 or Palmyra X6 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Claude Fable 5.1 leans toward terminal-bench-science agentic research (52.6%, more than double fable 5's 24.7%) while Palmyra X6 leans toward enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Fable 5.1 or Palmyra X6?
Palmyra X6 is cheaper — $10/$50 per 1M tokens vs Not published.
Which has the bigger context window?
Claude Fable 5.1 — 1M tokens vs 128K, about 7.8× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Fable 5.1 and Palmyra X6 together?
Yes — a multi-model platform like LumiChats gives you Claude Fable 5.1, Palmyra X6 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Fable 5.1 or Palmyra X6?
Claude Fable 5.1 — released September 1, 2026, about 19 days after Palmyra X6.
Claude Fable 5.1 vs Palmyra X6
Anthropic · US | Writer · US · Updated June 2026
Quick verdict
Pick Claude Fable 5.1 for terminal-bench-science agentic research (52.6%, more than double fable 5's 24.7%) or cursorbench 3.2 agentic coding (73.4%). Pick Palmyra X6 for enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents or writer says its harness upgrades cut agent-workflow token costs by roughly 52% and improve speed by roughly 48% (writer's own figures). On a tight budget at scale, Palmyra X6 is the value pick.
Claude Fable 5.1 (Anthropic) and Palmyra X6 (Writer) are two of the models people most often weigh against each other in 2026. Claude Fable 5.1 is anthropic's September 1, 2026 update to its Fable line for coding and knowledge work, keeping the 1M-token context of Fable 5 while cutting cache-read costs and roughly doubling agentic-research benchmark scores. Palmyra X6 is writer's enterprise agentic flagship - a GLM-5.2-based model with harness upgrades Writer says cut agent token costs by roughly half. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
▸Context window: Claude Fable 5.1 holds 7.8× more — 1M tokens (~1,500 pages) vs 128K (~192 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
▸Recency: Claude Fable 5.1 is the newer model by about 19 days (released September 1, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Fable 5.1
Palmyra X6
Provider
Anthropic (US)
Writer (US)
Released
September 1, 2026
August 13, 2026
Context window
1M tokens (~1,500 pages)
128K (~192 pages)
Price (in/out)
$10/$50 per 1M tokens
Not published
Open weight?
No — API only
No — API only
Modalities
text, image
text, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Terminal-Bench-Science agentic research (52.6%, more than double Fable 5's 24.7%)
Claude Fable 5.1
Palmyra X6 is comparatively weak here — not independently benchmarked on general leaderboards like SWE-bench or Artificial Analysis
CursorBench 3.2 agentic coding (73.4%)
Claude Fable 5.1
Anthropic's September 1, 2026 update to its Fable line for coding and knowledge work, keeping the 1M-token context of Fable 5 while cutting cache-read costs and roughly doubling agentic-research benchmark scores — and it carries the larger 1M tokens context.
Cache-read pricing cut to a quarter of other Claude models
Claude Fable 5.1
Anthropic's September 1, 2026 update to its Fable line for coding and knowledge work, keeping the 1M-token context of Fable 5 while cutting cache-read costs and roughly doubling agentic-research benchmark scores — and it is the newer of the two.
Enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents
Palmyra X6
Palmyra X6 lists enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents among its strengths; Claude Fable 5.1 does not.
Writer says its harness upgrades cut agent-workflow token costs by roughly 52% and improve speed by roughly 48% (Writer's own figures)
Palmyra X6
Palmyra X6 lists writer says its harness upgrades cut agent-workflow token costs by roughly 52% and improve speed by roughly 48% (Writer's own figures) among its strengths; Claude Fable 5.1 does not.
A post-trained variant built on Z.ai's open-weight GLM-5.2, tuned specifically for business agent use
Palmyra X6
Claude Fable 5.1 is comparatively weak here — restricted Mythos 5.1 variant outscores it on some benchmarks due to lighter safeguards (Terminal-Bench 4.0: 60.9% vs 55.8%)
Lowest cost at scale
Palmyra X6
Its weights are open, so at volume you pay for your own hardware instead of Claude Fable 5.1's $10/$50 per 1M tokens.
Largest single-prompt input
Claude Fable 5.1
Its 1M tokens window is about 7.8× larger than Palmyra X6's 128K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Palmyra X6
At Not published it undercuts Claude Fable 5.1, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Claude Fable 5.1
Larger 1M tokens window fits more in one prompt.
Anyone whose priority is terminal-bench-science agentic research (52.6%, more than double fable 5's 24.7%)
→ Claude Fable 5.1
It is specifically built for that.
Anyone whose priority is enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents
→ Palmyra X6
That is its strongest area.
Claude Fable 5.1: where it fits
Anthropic's September 1, 2026 update to its Fable line for coding and knowledge work, keeping the 1M-token context of Fable 5 while cutting cache-read costs and roughly doubling agentic-research benchmark scores. Released September 1, 2026 by Anthropic, it is built for terminal-Bench-Science agentic research (52.6%, more than double Fable 5's 24.7%), cursorBench 3.2 agentic coding (73.4%), cache-read pricing cut to a quarter of other Claude models, and long, multistep, document-heavy professional work with 1M-token context.
Its trade-offs are real: anthropic has not published an official SWE-bench Verified score for this model, restricted Mythos 5.1 variant outscores it on some benchmarks due to lighter safeguards (Terminal-Bench 4.0: 60.9% vs 55.8%), and closed weights, no self-hosting option. At $10 in / $50 out per million tokens, it sits in the premium price band.
Palmyra X6: where it fits
Writer's enterprise agentic flagship - a GLM-5.2-based model with harness upgrades Writer says cut agent token costs by roughly half. Released August 13, 2026 by Writer, it is built for enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents, writer says its harness upgrades cut agent-workflow token costs by roughly 52% and improve speed by roughly 48% (Writer's own figures), and a post-trained variant built on Z.ai's open-weight GLM-5.2, tuned specifically for business agent use.
Its trade-offs: no public per-token API price - sold through Writer's enterprise platform, not a self-serve API, not independently benchmarked on general leaderboards like SWE-bench or Artificial Analysis, and built for a narrower enterprise-agent use case rather than general-purpose chat.
The bottom line for this matchup
Claude Fable 5.1 and Palmyra X6 overlap enough that the right pick depends on your specific job. Palmyra X6 costs less per token; Claude Fable 5.1 holds the larger context; and each leads in its own area — Claude Fable 5.1 for terminal-bench-science agentic research (52.6%, more than double fable 5's 24.7%), Palmyra X6 for enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Fable 5.1 and Palmyra X6 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
Is Claude Fable 5.1 or Palmyra X6 better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Claude Fable 5.1 leans toward terminal-bench-science agentic research (52.6%, more than double fable 5's 24.7%) while Palmyra X6 leans toward enterprise agentic workflows - built specifically for marketing/revenue teams running multi-step agents, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Fable 5.1 or Palmyra X6?
Palmyra X6 is cheaper — $10/$50 per 1M tokens vs Not published.
Which has the bigger context window?
Claude Fable 5.1 — 1M tokens vs 128K, about 7.8× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Fable 5.1 and Palmyra X6 together?
Yes — a multi-model platform like LumiChats gives you Claude Fable 5.1, Palmyra X6 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Fable 5.1 or Palmyra X6?
Claude Fable 5.1 — released September 1, 2026, about 19 days after Palmyra X6.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.