Claude Mythos Preview vs GLM-5

Claude Mythos Preview (2026) and GLM-5 (2026) are frontier-tier reasoning models from Anthropic and Zhipu AI. Claude Mythos Preview ships a 1m-token context window, while GLM-5 ships a 200k-token context window. On SWE-bench Verified, Claude Mythos Preview leads by 16.1 pts. On pricing, GLM-5 costs $0.60/1M input tokens versus $25/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

GLM-5 is ~4067% cheaper at $0.60/1M; pay for Claude Mythos Preview only for coding workflow support.

Decision scorecard

Local evidence first
SignalClaude Mythos PreviewGLM-5
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsreasoning-heavy apps, tool-calling agents, and provider-routed production
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window1m200k
Cheapest output$125/1M tokens$2.08/1M tokens
Provider routes2 tracked7 tracked
Shared benchmarksSWE-bench Verified leader3 shared

Decision tradeoffs

Choose Claude Mythos Preview when...
  • Claude Mythos Preview holds a shared-benchmark lead on SWE-bench Verified, ahead by 16.1 points.
  • Claude Mythos Preview has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Claude Mythos Preview uniquely exposes Vision, Multimodal, and Code execution in local model data.
  • Local decision data tags Claude Mythos Preview for Coding, RAG, and Agents.
Choose GLM-5 when...
  • GLM-5 has the lower cheapest tracked output price at $2.08/1M tokens.
  • GLM-5 has broader tracked provider coverage for fallback and route flexibility.
  • Local decision data tags GLM-5 for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate GLM-5

Claude Mythos Preview

$51,250

Cheapest tracked route/tier: Anthropic

GLM-5

$1,000

Cheapest tracked route/tier: OpenRouter

Estimated monthly gap: $50,250. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Mythos Preview -> GLM-5
  • No overlapping tracked provider route is sourced for Claude Mythos Preview and GLM-5; plan for SDK, billing, or endpoint changes.
  • GLM-5 is $123/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Vision, Multimodal, and Code execution before moving production traffic.
GLM-5 -> Claude Mythos Preview
  • No overlapping tracked provider route is sourced for GLM-5 and Claude Mythos Preview; plan for SDK, billing, or endpoint changes.
  • Claude Mythos Preview is $123/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Claude Mythos Preview adds Vision, Multimodal, and Code execution in local capability data.

Specs

Specification
Released2026-05-012026-02-11
Context window1m200k
Parameters—744B total, 40B active
ArchitectureDecoder OnlyMixture of Experts
LicenseProprietaryMITOSI-approved
OpennessProprietaryOpen source
WeightsNot releasedAvailable
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: permitted
Knowledge cutoff2025-122025-11

Pricing and availability

Pricing attributeClaude Mythos PreviewGLM-5
Input price$25/1M tokens$0.60/1M tokens
Output price$125/1M tokens$2.08/1M tokens
Providers
AnthropicMicrosoft Foundry
Fireworks AIOpenRouterTogether AIGCP Vertex AINVIDIA NIMVercel AI Gateway

Capabilities

CapabilityClaude Mythos PreviewGLM-5
VisionYesNo
MultimodalYesNo
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkClaude Mythos PreviewGLM-5
SWE-bench Verified93.977.8
Google-Proof Q&A94.686.0
τ-bench89.282.1

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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.