GCP Vertex AI exposes Claude Mythos 5.1 through model ID claude-mythos-5-1. Use the setup steps, sourced pricing, capabilities, and official provider links below to validate this route before deployment.
Last refreshed 2026-09-01. Next refresh: weekly.
Quick Start
- 1
- 2Use the GCP Vertex AI SDK or REST API to call
claude-mythos-5-1— see the documentation for request format.
Code Examples
pip install google-cloud-aiplatformGOOGLE_CLOUD_PROJECTclaude-mythos-5-1For 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".
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)Pricing on GCP Vertex AI
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.