1.48.0: _cache_buckets raises AttributeError on litellm PromptTokensDetailsWrapper

What happens

Every completion() whose provider reports no cache-creation tokens raises:

AttributeError: 'PromptTokensDetailsWrapper' object has no attribute 'cache_creation_tokens'

from openhands/sdk/llm/utils/telemetry.py, in Telemetry._cache_buckets.

Why

cache_write = (
    details.cache_creation_tokens
    if "cache_creation_tokens" in details.model_fields_set
    else 0
)

model_fields_set is not a safe test for this object. litellm's
PromptTokensDetailsWrapper extends SafeAttributeModel, which removes
attributes whose value is None — but the field name stays in
model_fields_set, because it was set at construction. So the guard passes
and the attribute access fails.

Reproduction

litellm 1.100.1, openhands-sdk 1.48.0:

from litellm.types.utils import PromptTokensDetailsWrapper

d = PromptTokensDetailsWrapper(cached_tokens=5, cache_creation_tokens=None)
print(sorted(d.model_fields_set))      # ['cache_creation_tokens', 'cache_write_tokens', 'cached_tokens']
print(hasattr(d, "cache_creation_tokens"))  # False
d.cache_creation_tokens                # AttributeError

Suggested fix

getattr(details, "cache_creation_tokens", 0), which is what 1.47.0 did and
what the sibling usage-level reads a few lines above still do.

Versions

• openhands-sdk 1.48.0 (also present on main as of 2026-09-16)
• litellm 1.100.1

1.47.0 is unaffected.

Start in openhands/sdk/llm/utils/telemetry.py at Telemetry._cache_buckets, then compare its cache-creation read with the sibling usage-level reads above. Reproduce with the PromptTokensDetailsWrapper example from the issue and verify that completion() no longer raises AttributeError when cache-creation tokens are absent.