One-install Twilio API front door over four bounded feature packs and five workflows. It admits 186 of 197 operations from the hash-pinned Twilio 2010-04-01 OpenAPI document. The compatibility root preserves 21 safe prior operation IDs, routes, argument keys, approval contracts, and cache behavior while dependencies add 165 operations. The former account.read route is intentionally removed because Twilio returns auth_token in the Account response. Seven credential-bearing responses, two credential-bearing SIP writes, and one live validation-code response are excluded fail-closed. New reads are uncached and require no approval, every new mutation requires approval, form mutations use closed typed fields, and unsafe JSON integers remain exact strings.