Pick Claude Opus 5.5 for performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 or anthropic reports it surpasses fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning. Pick Muse Glimmer for runs real agentic tasks locally on one consumer gpu - fits 24gb of vram in 4-bit or open weights (apache 2.0), free to self-host and offline-capable - data never leaves your machine. Choose Muse Glimmer if you need self-hosting or data privacy; Claude Opus 5.5 if you want a managed API.
Claude Opus 5.5 (Anthropic) and Muse Glimmer (Meta) are two of the models people most often weigh against each other in 2026. Claude Opus 5.5 is anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Muse Glimmer is meta's open ~30B agentic model - runs tool-using AI agents locally on a single consumer GPU, offline and free, though it trails frontier cloud models. They diverge most on price, context window and open vs. closed weights — each quantified below from the models' real specs.
Key differences
Cost model: Muse Glimmer ships open weights you can self-host (hardware cost only, no per-token fee), while Claude Opus 5.5 is API-metered at $4/$20 per 1M tokens. Your choice depends on whether you want zero marginal cost at the price of running infrastructure.
Context window: Claude Opus 5.5 holds 7.6× more — 1M tokens (~1,500 pages) vs 128K (~197 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 Opus 5.5 is the newer model by about 43 days (released September 22, 2026), usually meaning fresher training data and capabilities.
Specifications
Spec
Claude Opus 5.5
Muse Glimmer
Provider
Anthropic (US)
Meta (US)
Released
September 22, 2026
August 10, 2026
Context window
1M tokens (~1,500 pages)
128K (~197 pages)
Price (in/out)
$4/$20 per 1M tokens
Open weight (self-host / free)
Open weight?
No — API only
Yes — self-hostable
Modalities
text, image, code
text, image, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5: Claude Opus 5.5 — Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching — and it carries the larger 1M tokens context.
Anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning: Claude Opus 5.5 — Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching — and it is the newer of the two.
Pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok: Claude Opus 5.5 — Its 1M tokens window holds about 7.6× more than Muse Glimmer's 128K in a single prompt.
Runs real agentic tasks locally on one consumer GPU - fits 24GB of VRAM in 4-bit: Muse Glimmer — Open weights make this possible at all — Claude Opus 5.5 is API-only, so it cannot leave the vendor's servers.
Open weights (Apache 2.0), free to self-host and offline-capable - data never leaves your machine: Muse Glimmer — Meta's open ~30B agentic model - runs tool-using AI agents locally on a single consumer GPU, offline and free, though it trails frontier cloud models — and its weights are open while Claude Opus 5.5 is API-only.
Agentic by design: tool use, coding, file and screenshot reading, multi-step failure recovery: Muse Glimmer — Muse Glimmer lists agentic by design: tool use, coding, file and screenshot reading, multi-step failure recovery among its strengths; Claude Opus 5.5 does not.
Lowest cost at scale: Muse Glimmer — Its weights are open, so at volume you pay for your own hardware instead of Claude Opus 5.5's $4/$20 per 1M tokens.
Largest single-prompt input: Claude Opus 5.5 — Its 1M tokens window is about 7.6× larger than Muse Glimmer's 128K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Muse Glimmer — At Open weight (self-host / free) it undercuts Claude Opus 5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Claude Opus 5.5 — Larger 1M tokens window fits more in one prompt.
A team with data-privacy or self-hosting needs: Muse Glimmer — Open weights let you run it on your own hardware; Claude Opus 5.5 is API-only.
Anyone whose priority is performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5: Claude Opus 5.5 — It is specifically built for that.
Anyone whose priority is runs real agentic tasks locally on one consumer gpu - fits 24gb of vram in 4-bit: Muse Glimmer — That is its strongest area.
Claude Opus 5.5: where it fits
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Released September 22, 2026 by Anthropic, it is built for performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5, anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning, pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok, and output speed increased over 30% versus Opus 5.
Its trade-offs are real: not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright, like Opus 5, the headline 1M-token context is not uniformly available across every platform and plan — some API paths default to a smaller window, and first model in the 5.5 line; Anthropic has signaled Sonnet 5.5 and Haiku 5.5 are still weeks away, so the lower tiers of the family aren't out yet. At $4 in / $20 out per million tokens, it sits in the mid price band.
Muse Glimmer: where it fits
Meta's open ~30B agentic model - runs tool-using AI agents locally on a single consumer GPU, offline and free, though it trails frontier cloud models. Released August 10, 2026 by Meta, it is built for runs real agentic tasks locally on one consumer GPU - fits 24GB of VRAM in 4-bit, open weights (Apache 2.0), free to self-host and offline-capable - data never leaves your machine, agentic by design: tool use, coding, file and screenshot reading, multi-step failure recovery, and 128K context, text and image input, trained on 100+ languages.
Its trade-offs: a distilled ~30B model - ceiling below its closed teacher (Muse Spark) and cloud flagships, no independent Artificial Analysis intelligence score published yet, published benchmarks (e.g. SWE-Bench Verified 76.0) are Meta's own, and 4-bit quantization to fit consumer GPUs trades away some accuracy. As an open-weight model, its running cost is your own hardware rather than a per-token fee.
The bottom line for this matchup
The defining split here is open vs. closed. Muse Glimmer gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. Claude Opus 5.5 gives you a managed, always-updated API with no infrastructure to run. Teams with GPUs, privacy requirements, or huge volume often favour the open model; teams that want zero ops and the latest capabilities favour the closed one. Capability is close enough that this operational question, not the benchmark, usually decides it.
Frequently asked questions
Is Claude Opus 5.5 or Muse Glimmer 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 Opus 5.5 leans toward performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 while Muse Glimmer leans toward runs real agentic tasks locally on one consumer gpu - fits 24gb of vram in 4-bit, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or Muse Glimmer?
Muse Glimmer is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while Claude Opus 5.5 is API-metered at $4/$20 per 1M tokens. For most teams without GPUs, the API model is cheaper to start; at very high volume, self-hosting can win.
Which has the bigger context window?
Claude Opus 5.5 — 1M tokens vs 128K, about 7.6× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Opus 5.5 and Muse Glimmer together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, Muse Glimmer 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 Opus 5.5 or Muse Glimmer?
Claude Opus 5.5 — released September 22, 2026, about 43 days after Muse Glimmer.
Claude Opus 5.5 vs Muse Glimmer
Anthropic · US | Meta · US · Updated June 2026
Quick verdict
Pick Claude Opus 5.5 for performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 or anthropic reports it surpasses fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning. Pick Muse Glimmer for runs real agentic tasks locally on one consumer gpu - fits 24gb of vram in 4-bit or open weights (apache 2.0), free to self-host and offline-capable - data never leaves your machine. Choose Muse Glimmer if you need self-hosting or data privacy; Claude Opus 5.5 if you want a managed API.
Claude Opus 5.5 (Anthropic) and Muse Glimmer (Meta) are two of the models people most often weigh against each other in 2026. Claude Opus 5.5 is anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Muse Glimmer is meta's open ~30B agentic model - runs tool-using AI agents locally on a single consumer GPU, offline and free, though it trails frontier cloud models. They diverge most on price, context window and open vs. closed weights — each quantified below from the models' real specs.
Key differences at a glance
▸Cost model: Muse Glimmer ships open weights you can self-host (hardware cost only, no per-token fee), while Claude Opus 5.5 is API-metered at $4/$20 per 1M tokens. Your choice depends on whether you want zero marginal cost at the price of running infrastructure.
▸Context window: Claude Opus 5.5 holds 7.6× more — 1M tokens (~1,500 pages) vs 128K (~197 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 Opus 5.5 is the newer model by about 43 days (released September 22, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
Spec
Claude Opus 5.5
Muse Glimmer
Provider
Anthropic (US)
Meta (US)
Released
September 22, 2026
August 10, 2026
Context window
1M tokens (~1,500 pages)
128K (~197 pages)
Price (in/out)
$4/$20 per 1M tokens
Open weight (self-host / free)
Open weight?
No — API only
Yes — self-hostable
Modalities
text, image, code
text, image, code
SWE-Bench Verified
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5
Claude Opus 5.5
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching — and it carries the larger 1M tokens context.
Anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning
Claude Opus 5.5
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching — and it is the newer of the two.
Pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok
Claude Opus 5.5
Its 1M tokens window holds about 7.6× more than Muse Glimmer's 128K in a single prompt.
Runs real agentic tasks locally on one consumer GPU - fits 24GB of VRAM in 4-bit
Muse Glimmer
Open weights make this possible at all — Claude Opus 5.5 is API-only, so it cannot leave the vendor's servers.
Open weights (Apache 2.0), free to self-host and offline-capable - data never leaves your machine
Muse Glimmer
Meta's open ~30B agentic model - runs tool-using AI agents locally on a single consumer GPU, offline and free, though it trails frontier cloud models — and its weights are open while Claude Opus 5.5 is API-only.
Agentic by design: tool use, coding, file and screenshot reading, multi-step failure recovery
Muse Glimmer
Muse Glimmer lists agentic by design: tool use, coding, file and screenshot reading, multi-step failure recovery among its strengths; Claude Opus 5.5 does not.
Lowest cost at scale
Muse Glimmer
Its weights are open, so at volume you pay for your own hardware instead of Claude Opus 5.5's $4/$20 per 1M tokens.
Largest single-prompt input
Claude Opus 5.5
Its 1M tokens window is about 7.6× larger than Muse Glimmer's 128K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Muse Glimmer
At Open weight (self-host / free) it undercuts Claude Opus 5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Claude Opus 5.5
Larger 1M tokens window fits more in one prompt.
A team with data-privacy or self-hosting needs
→ Muse Glimmer
Open weights let you run it on your own hardware; Claude Opus 5.5 is API-only.
Anyone whose priority is performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5
→ Claude Opus 5.5
It is specifically built for that.
Anyone whose priority is runs real agentic tasks locally on one consumer gpu - fits 24gb of vram in 4-bit
→ Muse Glimmer
That is its strongest area.
Claude Opus 5.5: where it fits
Anthropic's September 22, 2026 update: Fable 5.1-level performance at 40% lower cost than Opus 5, with faster output and cheaper caching. Released September 22, 2026 by Anthropic, it is built for performs at roughly Claude Fable 5.1's level on most work, at 40% lower typical workload cost than Opus 5, anthropic reports it surpasses Fable 5.1 on agentic coding, knowledge work, computer use, visual chart recognition, and multidisciplinary reasoning, pricing cut to $4/$20 per million tokens (20% below Opus 5's $5/$25), cache reads down 60% to $0.20/MTok, and output speed increased over 30% versus Opus 5.
Its trade-offs are real: not a reasoning-ceiling upgrade over Fable 5.1 — pitched as matching its performance at lower cost, not beating it outright, like Opus 5, the headline 1M-token context is not uniformly available across every platform and plan — some API paths default to a smaller window, and first model in the 5.5 line; Anthropic has signaled Sonnet 5.5 and Haiku 5.5 are still weeks away, so the lower tiers of the family aren't out yet. At $4 in / $20 out per million tokens, it sits in the mid price band.
Muse Glimmer: where it fits
Meta's open ~30B agentic model - runs tool-using AI agents locally on a single consumer GPU, offline and free, though it trails frontier cloud models. Released August 10, 2026 by Meta, it is built for runs real agentic tasks locally on one consumer GPU - fits 24GB of VRAM in 4-bit, open weights (Apache 2.0), free to self-host and offline-capable - data never leaves your machine, agentic by design: tool use, coding, file and screenshot reading, multi-step failure recovery, and 128K context, text and image input, trained on 100+ languages.
Its trade-offs: a distilled ~30B model - ceiling below its closed teacher (Muse Spark) and cloud flagships, no independent Artificial Analysis intelligence score published yet, published benchmarks (e.g. SWE-Bench Verified 76.0) are Meta's own, and 4-bit quantization to fit consumer GPUs trades away some accuracy. As an open-weight model, its running cost is your own hardware rather than a per-token fee.
The bottom line for this matchup
The defining split here is open vs. closed. Muse Glimmer gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. Claude Opus 5.5 gives you a managed, always-updated API with no infrastructure to run. Teams with GPUs, privacy requirements, or huge volume often favour the open model; teams that want zero ops and the latest capabilities favour the closed one. Capability is close enough that this operational question, not the benchmark, usually decides it.
Want both Claude Opus 5.5 and Muse Glimmer 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 Opus 5.5 or Muse Glimmer 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 Opus 5.5 leans toward performs at roughly claude fable 5.1's level on most work, at 40% lower typical workload cost than opus 5 while Muse Glimmer leans toward runs real agentic tasks locally on one consumer gpu - fits 24gb of vram in 4-bit, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Opus 5.5 or Muse Glimmer?
Muse Glimmer is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while Claude Opus 5.5 is API-metered at $4/$20 per 1M tokens. For most teams without GPUs, the API model is cheaper to start; at very high volume, self-hosting can win.
Which has the bigger context window?
Claude Opus 5.5 — 1M tokens vs 128K, about 7.6× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Opus 5.5 and Muse Glimmer together?
Yes — a multi-model platform like LumiChats gives you Claude Opus 5.5, Muse Glimmer 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 Opus 5.5 or Muse Glimmer?
Claude Opus 5.5 — released September 22, 2026, about 43 days after Muse Glimmer.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.