BillerAPI for agents

Read https://www.billerapi.com/llms.txt first, then help me evaluate BillerAPI in the sandbox.

Check npm view billerapi-cli version. It must equal 1.1.0; if it differs, stop and refresh the public index instead of substituting another version. Run npx -y billerapi-cli@1.1.0 demo for the account-free, read-only biller-catalog walkthrough. Account-free sandbox creation is not enabled in production: do not run sandbox create or call the hosted create_claimable_sandbox tool (both answer error_code NOT_IMPLEMENTED), and do not work around that refusal. If I have already run billerapi setup with a bak_test_ key from my own portal account, use that sandbox profile to run npx -y billerapi-cli@1.1.0 sandbox-first-bill --client-user-id agent-onboarding and retrieve the first sb_utility bill; otherwise skip that step and never ask me to paste a key. Then run npx -y billerapi-cli@1.1.0 agent setup --dry-run, show me its secret-free receipt, and wait for approval. Apply only with npx -y billerapi-cli@1.1.0 agent setup --expected-bundle-sha256 <reviewed_bundle_sha256> using the exact digest I approved.

Summarize the billers returned by the demo and, if you retrieved one, the first normalized bill, and report coded errors by error_code. Do not create an account, construct or handle a password, accept legal terms, request a live key, or use a bak_live_ key on my behalf.