What

_get_usage computes prompt_tokens as input_tokens + cache_read_input_tokens (Anthropic reports cached prompt tokens separately, so they have to be added back), but total_tokens was left as just input_tokens + output_tokens. As soon as prompt caching kicks in, total_tokens is smaller than prompt_tokens + completion_tokens, which breaks anything downstream that assumes the totals add up (cost tracking, budget/limit checks).

Concrete example with a cached prompt: input_tokens=500, cache_read_input_tokens=10000, output_tokens=200 gives prompt_tokens=10500, completion_tokens=200, but total_tokens=700 instead of 10700.

This affects both ChatAnthropic (browser_use/llm/anthropic/chat.py) and ChatAnthropicBedrock (browser_use/llm/aws/chat_anthropic.py), which share the same usage logic.

Fix

Add the cache-read tokens to total_tokens so it mirrors the prompt_tokens formula and the invariant total_tokens == prompt_tokens + completion_tokens holds again. One line per file.

Verifying

Added tests/ci/models/test_anthropic_usage.py covering both clients: the cached case (asserts the totals add up) and the no-cache case (asserts the number is unchanged).

uv run pytest tests/ci/models/test_anthropic_usage.py -q

The cached-case assertions fail on current main (700 != 10700) and pass with this change; the no-cache case stays at 700 both ways. ruff check / ruff format clean on the touched files.

Note: #4294 proposed the same one-liner for chat.py but went stale before it landed, and it never touched the Bedrock client. This covers both and adds a regression test.

Summary by cubic

Fixes Anthropic usage accounting by adding cache-read prompt tokens to total_tokens, restoring total_tokens == prompt_tokens + completion_tokens. Applies to both Anthropic and Bedrock clients.

• Bug Fixes
  • Include cache_read_input_tokens in total_tokens in browser_use/llm/anthropic/chat.py and browser_use/llm/aws/chat_anthropic.py.
  • Add tests/ci/models/test_anthropic_usage.py for cached/no-cache cases and type the mock response helper for Pyright.

^{Written for commit 42351e4. Summary will update on new commits.}