fix(model_prices): bedrock Grok 4.6 does not support prompt caching

[FahimaGold]

Problem

us.xai.grok-4.6 and global.xai.grok-4.6 (litellm_provider: bedrock_converse) are marked supports_prompt_caching: true in the model cost map. AWS Bedrock does not support prompt caching for Grok.

With litellm.enable_anthropic_prompt_caching enabled, AnthropicCacheControlHook.get_default_injection_points treats the flag as authoritative and auto-injects cache_control breakpoints for these models. Bedrock then rejects the entire request:

BedrockException — "You invoked an unsupported model or your request did not allow prompt caching."

The result is a 100% failure rate for Bedrock-hosted Grok 4.6 whenever auto prompt-caching is on. Reproduced live against Bedrock across regions.

The wrong flag came in with #37517 (which added these rows). The offline bundled map lags remote, which is why it isn't always visible in local runs.

Fix

For both us.xai.grok-4.6 and global.xai.grok-4.6:

• supports_prompt_caching: true → false
• remove cache_read_input_token_cost (a cache-read price is meaningless once caching is unsupported, and leaving it keeps the row self-contradictory)

Applied identically to model_prices_and_context_window.json and the bundled litellm/model_prices_and_context_window_backup.json. Native xAI Grok (xai/grok-4.6) is a separate entry and is untouched.

Note for maintainers

bedrock_mantle/xai.grok-4.6 is also marked supports_prompt_caching: true (added in the same #37517). It's the same model on the same platform, so it's very likely affected too — but I only reproduced the bedrock_converse path, so I've left it out of this PR. Happy to include it if you can confirm Bedrock caching is unsupported on the Mantle route as well.

Tests

tests/test_litellm/test_bedrock_grok_prompt_caching_metadata.py — data-level (reads the JSON files directly, so it isn't affected by remote-map refresh): asserts supports_prompt_caching is false, no cache_read_input_token_cost remains, and the root map and bundled backup agree for these rows. Fails on the pre-fix map, passes with the fix.

[greptile-apps]

Greptile Summary

The PR corrects prompt-caching capability and pricing metadata for the two Bedrock Converse Grok 4.6 model identifiers.

• Disables prompt caching and removes cache-read pricing in both model maps.
• Relocates the regression coverage into the existing Anthropic cache-control hook test suite.
• Verifies that both affected models report caching as unsupported and receive no automatic cache-control injection.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains, and the previously reported test-organization issue has been fixed by moving the regression into the existing cache-control hook test module.

Important Files Changed

Filename	Overview
model_prices_and_context_window.json	Correctly disables prompt caching and removes obsolete cache-read pricing for both Bedrock Converse Grok 4.6 entries.
litellm/model_prices_and_context_window_backup.json	Mirrors the root model-map corrections for the bundled fallback metadata.
tests/test_litellm/integrations/test_anthropic_cache_control_hook.py	Places the regression test beside the affected hook behavior and covers both model identifiers using the local model-cost map.

_{Reviews (2): Last reviewed commit: "test: move Bedrock Grok caching regressi..." | Re-trigger Greptile}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[FahimaGold]

@greptileai review

[codspeed-hq]

Merging this PR will not alter performance

✅ 31 untouched benchmarks

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_{Comparing FahimaGold:fix/bedrock-grok-no-prompt-caching (fbd65d9) with litellm_internal_staging (b724ebc)¹}

Footnotes

1. No successful run was found on litellm_internal_staging (63dd18c) during the generation of this report, so b724ebc was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[devin-ai-integration]

Superseded by the rolling registry PR #38693, which re-verified these Bedrock Grok 4.6 caching changes against the AWS docs.