Fix anthropic toolcall bug #5780

Job	Run time
build-and-check	2m 51s
test-integration-common	41s
test-integration-sdk	47s
test-integration-packages/billing	1m 3s
test-integration-packages/internal	1m 10s
test-packages/billing	40s
test-web	51s
test-integration-web	46s
test-.agents	43s
test-integration-cli	39s
test-packages/agent-runtime	1m 5s
test-sdk	45s
test-cli	59s
test-common	48s
test-integration-packages/agent-runtime	48s
test-packages/internal	49s
	15m 25s

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