Config mismatch: Fantasy doesn't respect `context_window` from Catwalk provider configs

[ivan-cstv]

Description

5 Fantasy v0.7.0 appears to ignore the context_window value from Catwalk provider configurations when determining the token budget for AI agents. This results in agents always using a 200K token limit, even when the provider config explicitly specifies 1M tokens. In this specific case we were trying to enable Claude 4.5 with a 1M token header via Bedrock or Anthropic API

Version

v0.7.0

Environment

Fantasy version:v0.7.0 | Catwalk version: v0.16.1

[andreynering]

Hi @ivan-cstv 👋

Can you let me know if this is still an issue?

Anthropic required a beta flag to use 1M context windows until recently, when they just made it the default.

See:

• chore: add 1m tokens support to opus 4.6 and sonnet 4.6 catwalk#214
• https://claude.com/blog/1m-context-ga

This might explain why it wasn't working for you.