Last refreshed 2026-09-01. Next refresh: weekly.
Why use Claude Mythos 5.1 on GCP Vertex AI?
GCP Vertex AI offers Claude Mythos 5.1 with competitive pricing. Vertex AI is Google Cloud's managed AI platform, offering access to Gemini models and hundreds of partner models alongside tools for fine-tuning, grounding, vector search, and end-to-end MLOps pipelines.
Compare Claude Mythos 5.1 across 4 providers to find the best fit for your use caseSetup recipe
Python + curlpip install google-cloud-aiplatformexport GOOGLE_CLOUD_PROJECT=...import os
import vertexai
from vertexai.generative_models import GenerativeModel
vertexai.init(project=os.environ["GOOGLE_CLOUD_PROJECT"], location="us-central1")claude-mythos-5-1Request example
import os
import vertexai
from vertexai.generative_models import GenerativeModel
# Reads GOOGLE_CLOUD_PROJECT from env; authenticates via Application Default Credentials
vertexai.init(project=os.environ["GOOGLE_CLOUD_PROJECT"], location="us-central1")
model = GenerativeModel("claude-mythos-5-1")
response = model.generate_content("Hello")
print(response.text)Gotchas
- For Google-published models use the model name directly, e.g. "gemini-2.0-flash-001". For third-party publishers (Anthropic, Meta, etc.) use the full publisher path, e.g. "publishers/anthropic/models/claude-3-5-sonnet-v2@20241022".
- The examples expect GOOGLE_CLOUD_PROJECT; rename it only if your application config maps the new variable.
Compare Claude Mythos 5.1 Across Providers
| Provider | Input (per 1M) | Output (per 1M) |
|---|---|---|
| Anthropic | $10.00 | $50.00 |
| AWS Bedrock | — | — |
| GCP Vertex AI | — | — |
| Microsoft Foundry | $10.00 | $50.00 |
Capabilities
About Claude Mythos 5.1
Anthropic's invitation-only Mythos-class model, released September 1, 2026. Same underlying model as Claude Fable 5.1 without the cybersecurity and biology safeguards. Access is limited to a small set of vetted organizations through trusted access / Project Glasswing; Anthropic currently makes it available to a set of US organizations and is working to expand. Claude API id claude-mythos-5-1. Pricing starts at $10 per 1M input tokens and $50 per 1M output tokens (limited availability; no cheaper public tier published). Cache reads $0.25 per 1M. 1M-token context, 128K max output, adaptive thinking always on, text and image input to text output.