{"abstract":"\"4255501...\" is read as code 2... and the dial string is wrong.","category":"Phone number formatting","checks":9,"contract":"Input [canonical +digits, caller country]. Toy table (code, exit prefix, trunk): DD 8/00/-, AA 42/00/0, BB 83/810/8, CC 891/011/-. The input must be \"+\" and digits only. The destination is the longest matching code. Same code as the caller: dial trunk + national number. Otherwise dial the caller exit prefix + code + national number. Unknown caller or code returns None.","contract_signature":"x","evaluation_group":"w2-phone-number-formatting-dial-string","failed_approach":"Stripping an optional plus accepts national-looking digits as if they were canonical.","family":"w2-phone-number-formatting-dial-string-plus-required","id":"FA-96521","implementations":{"attempt":{"sha256":"ef95a7c1f9733700731ca39afadc9bbc8af86736e095421243bbdc3130f779da","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    e164, frm = x\n    TABLE = {'DD': ('8', '00', ''), 'AA': ('42', '00', '0'), 'BB': ('83', '810', '8'), 'CC': ('891', '011', '')}\n    if frm not in TABLE or not e164[1:].isdigit():\n        return None\n    digits = e164.lstrip('+')\n    cc = max((v[0] for v in TABLE.values() if digits.startswith(v[0])), key=len, default=None)\n    if cc is None:\n        return None\n    nsn = digits[len(cc):]\n    own_cc, exit_prefix, trunk = TABLE[frm]\n    if cc == own_cc:\n        return trunk + nsn\n    return exit_prefix + cc + nsn\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['domestic call adds trunk', ['+42555011123', 'AA'], '0555011123'], ['domestic call without trunk', ['+8915550135', 'CC'], '5550135'], ['caller code is a prefix of destination code', ['+835550121221', 'DD'], '00835550121221'], ['destination code is a prefix of caller code', ['+8555010141', 'BB'], '8108555010141'], ['three-digit exit prefix', ['+8915550135', 'AA'], '008915550135'], ['spaced E.164 rejected', ['+42 555011123', 'AA'], None], ['missing plus rejected', ['42555011123', 'AA'], None], ['leading zero instead of plus rejected', ['042555011123', 'AA'], None], ['unknown caller country', ['+42555011123', 'ZZ'], None]], [['domestic call adds trunk', ['+42555012234', 'AA'], '0555012234'], ['domestic call without trunk', ['+8915550246', 'CC'], '5550246'], ['caller code is a prefix of destination code', ['+835550122332', 'DD'], '00835550122332'], ['destination code is a prefix of caller code', ['+8555010252', 'BB'], '8108555010252'], ['three-digit exit prefix', ['+8915550246', 'AA'], '008915550246'], ['spaced E.164 rejected', ['+42 555012234', 'AA'], None], ['missing plus rejected', ['42555012234', 'AA'], None], ['leading zero instead of plus rejected', ['042555012234', 'AA'], None], ['unknown caller country', ['+42555012234', 'ZZ'], None]], [['domestic call adds trunk', ['+42555013345', 'AA'], '0555013345'], ['domestic call without trunk', ['+8915550357', 'CC'], '5550357'], ['caller code is a prefix of destination code', ['+835550123443', 'DD'], '00835550123443'], ['destination code is a prefix of caller code', ['+8555010363', 'BB'], '8108555010363'], ['three-digit exit prefix', ['+8915550357', 'AA'], '008915550357'], ['spaced E.164 rejected', ['+42 555013345', 'AA'], None], ['missing plus rejected', ['42555013345', 'AA'], None], ['leading zero instead of plus rejected', ['042555013345', 'AA'], None], ['unknown caller country', ['+42555013345', 'ZZ'], None]], [['domestic call adds trunk', ['+42555014456', 'AA'], '0555014456'], ['domestic call without trunk', ['+8915550468', 'CC'], '5550468'], ['caller code is a prefix of destination code', ['+835550124554', 'DD'], '00835550124554'], ['destination code is a prefix of caller code', ['+8555010474', 'BB'], '8108555010474'], ['three-digit exit prefix', ['+8915550468', 'AA'], '008915550468'], ['spaced E.164 rejected', ['+42 555014456', 'AA'], None], ['missing plus rejected', ['42555014456', 'AA'], None], ['leading zero instead of plus rejected', ['042555014456', 'AA'], None], ['unknown caller country', ['+42555014456', 'ZZ'], None]], [['domestic call adds trunk', ['+42555015567', 'AA'], '0555015567'], ['domestic call without trunk', ['+8915550579', 'CC'], '5550579'], ['caller code is a prefix of destination code', ['+835550125665', 'DD'], '00835550125665'], ['destination code is a prefix of caller code', ['+8555010585', 'BB'], '8108555010585'], ['three-digit exit prefix', ['+8915550579', 'AA'], '008915550579'], ['spaced E.164 rejected', ['+42 555015567', 'AA'], None], ['missing plus rejected', ['42555015567', 'AA'], None], ['leading zero instead of plus rejected', ['042555015567', 'AA'], None], ['unknown caller country', ['+42555015567', 'ZZ'], None]]]\nfor label, arg, expected in fixtures[N - 1]:\n    check(label, solve(arg), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"bfef1f86252ef617b3d1f686fad865b9369a7ac472ca382b88bed2f3f20a88e6","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    e164, frm = x\n    TABLE = {'DD': ('8', '00', ''), 'AA': ('42', '00', '0'), 'BB': ('83', '810', '8'), 'CC': ('891', '011', '')}\n    if frm not in TABLE or not e164[1:].isdigit():\n        return None\n    digits = e164[1:]\n    cc = max((v[0] for v in TABLE.values() if digits.startswith(v[0])), key=len, default=None)\n    if cc is None:\n        return None\n    nsn = digits[len(cc):]\n    own_cc, exit_prefix, trunk = TABLE[frm]\n    if cc == own_cc:\n        return trunk + nsn\n    return exit_prefix + cc + nsn\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['domestic call adds trunk', ['+42555011123', 'AA'], '0555011123'], ['domestic call without trunk', ['+8915550135', 'CC'], '5550135'], ['caller code is a prefix of destination code', ['+835550121221', 'DD'], '00835550121221'], ['destination code is a prefix of caller code', ['+8555010141', 'BB'], '8108555010141'], ['three-digit exit prefix', ['+8915550135', 'AA'], '008915550135'], ['spaced E.164 rejected', ['+42 555011123', 'AA'], None], ['missing plus rejected', ['42555011123', 'AA'], None], ['leading zero instead of plus rejected', ['042555011123', 'AA'], None], ['unknown caller country', ['+42555011123', 'ZZ'], None]], [['domestic call adds trunk', ['+42555012234', 'AA'], '0555012234'], ['domestic call without trunk', ['+8915550246', 'CC'], '5550246'], ['caller code is a prefix of destination code', ['+835550122332', 'DD'], '00835550122332'], ['destination code is a prefix of caller code', ['+8555010252', 'BB'], '8108555010252'], ['three-digit exit prefix', ['+8915550246', 'AA'], '008915550246'], ['spaced E.164 rejected', ['+42 555012234', 'AA'], None], ['missing plus rejected', ['42555012234', 'AA'], None], ['leading zero instead of plus rejected', ['042555012234', 'AA'], None], ['unknown caller country', ['+42555012234', 'ZZ'], None]], [['domestic call adds trunk', ['+42555013345', 'AA'], '0555013345'], ['domestic call without trunk', ['+8915550357', 'CC'], '5550357'], ['caller code is a prefix of destination code', ['+835550123443', 'DD'], '00835550123443'], ['destination code is a prefix of caller code', ['+8555010363', 'BB'], '8108555010363'], ['three-digit exit prefix', ['+8915550357', 'AA'], '008915550357'], ['spaced E.164 rejected', ['+42 555013345', 'AA'], None], ['missing plus rejected', ['42555013345', 'AA'], None], ['leading zero instead of plus rejected', ['042555013345', 'AA'], None], ['unknown caller country', ['+42555013345', 'ZZ'], None]], [['domestic call adds trunk', ['+42555014456', 'AA'], '0555014456'], ['domestic call without trunk', ['+8915550468', 'CC'], '5550468'], ['caller code is a prefix of destination code', ['+835550124554', 'DD'], '00835550124554'], ['destination code is a prefix of caller code', ['+8555010474', 'BB'], '8108555010474'], ['three-digit exit prefix', ['+8915550468', 'AA'], '008915550468'], ['spaced E.164 rejected', ['+42 555014456', 'AA'], None], ['missing plus rejected', ['42555014456', 'AA'], None], ['leading zero instead of plus rejected', ['042555014456', 'AA'], None], ['unknown caller country', ['+42555014456', 'ZZ'], None]], [['domestic call adds trunk', ['+42555015567', 'AA'], '0555015567'], ['domestic call without trunk', ['+8915550579', 'CC'], '5550579'], ['caller code is a prefix of destination code', ['+835550125665', 'DD'], '00835550125665'], ['destination code is a prefix of caller code', ['+8555010585', 'BB'], '8108555010585'], ['three-digit exit prefix', ['+8915550579', 'AA'], '008915550579'], ['spaced E.164 rejected', ['+42 555015567', 'AA'], None], ['missing plus rejected', ['42555015567', 'AA'], None], ['leading zero instead of plus rejected', ['042555015567', 'AA'], None], ['unknown caller country', ['+42555015567', 'ZZ'], None]]]\nfor label, arg, expected in fixtures[N - 1]:\n    check(label, solve(arg), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"A deterministic toy contract over synthetic, obviously fictitious telephone numbers and toy country tables. The rules are stipulated for this model only and make no claim of conformance with any numbering plan or telecommunications standard. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-phone-number-formatting-dial-string-plus-required","generated_at":"2026-09-29T14:52:23.488569+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Click-to-call and PBX integrations dial the string produced here; a wrong prefix connects to a different subscriber or fails.","root_cause":"The leading plus is not required, but the first character is still skipped.","sha256":"febe45bed0cb28f6043def99d659523ed3b59f76854ccbc1fcd6d5d002d16ae9","title":"Dial string from E.164: numbers without the plus lose their first digit · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":36.254,"exit_code":1,"observations":[{"actual":"0555011123","check":"domestic call adds trunk","expected":"0555011123","passed":true},{"actual":"5550135","check":"domestic call without trunk","expected":"5550135","passed":true},{"actual":"00835550121221","check":"caller code is a prefix of destination code","expected":"00835550121221","passed":true},{"actual":"8108555010141","check":"destination code is a prefix of caller code","expected":"8108555010141","passed":true},{"actual":"008915550135","check":"three-digit exit prefix","expected":"008915550135","passed":true},{"actual":null,"check":"spaced E.164 rejected","expected":null,"passed":true},{"actual":"0555011123","check":"missing plus rejected","expected":null,"passed":false},{"actual":null,"check":"leading zero instead of plus rejected","expected":null,"passed":true},{"actual":null,"check":"unknown caller country","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"domestic call adds trunk\", \"actual\": \"0555011123\", \"expected\": \"0555011123\", \"passed\": true}, {\"check\": \"domestic call without trunk\", \"actual\": \"5550135\", \"expected\": \"5550135\", \"passed\": true}, {\"check\": \"caller code is a prefix of destination code\", \"actual\": \"00835550121221\", \"expected\": \"00835550121221\", \"passed\": true}, {\"check\": \"destination code is a prefix of caller code\", \"actual\": \"8108555010141\", \"expected\": \"8108555010141\", \"passed\": true}, {\"check\": \"three-digit exit prefix\", \"actual\": \"008915550135\", \"expected\": \"008915550135\", \"passed\": true}, {\"check\": \"spaced E.164 rejected\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing plus rejected\", \"actual\": \"0555011123\", \"expected\": null, \"passed\": false}, {\"check\": \"leading zero instead of plus rejected\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"unknown caller country\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.894,"exit_code":1,"observations":[{"actual":"0555011123","check":"domestic call adds trunk","expected":"0555011123","passed":true},{"actual":"5550135","check":"domestic call without trunk","expected":"5550135","passed":true},{"actual":"00835550121221","check":"caller code is a prefix of destination code","expected":"00835550121221","passed":true},{"actual":"8108555010141","check":"destination code is a prefix of caller code","expected":"8108555010141","passed":true},{"actual":"008915550135","check":"three-digit exit prefix","expected":"008915550135","passed":true},{"actual":null,"check":"spaced E.164 rejected","expected":null,"passed":true},{"actual":null,"check":"missing plus rejected","expected":null,"passed":true},{"actual":"0555011123","check":"leading zero instead of plus rejected","expected":null,"passed":false},{"actual":null,"check":"unknown caller country","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"domestic call adds trunk\", \"actual\": \"0555011123\", \"expected\": \"0555011123\", \"passed\": true}, {\"check\": \"domestic call without trunk\", \"actual\": \"5550135\", \"expected\": \"5550135\", \"passed\": true}, {\"check\": \"caller code is a prefix of destination code\", \"actual\": \"00835550121221\", \"expected\": \"00835550121221\", \"passed\": true}, {\"check\": \"destination code is a prefix of caller code\", \"actual\": \"8108555010141\", \"expected\": \"8108555010141\", \"passed\": true}, {\"check\": \"three-digit exit prefix\", \"actual\": \"008915550135\", \"expected\": \"008915550135\", \"passed\": true}, {\"check\": \"spaced E.164 rejected\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing plus rejected\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"leading zero instead of plus rejected\", \"actual\": \"0555011123\", \"expected\": null, \"passed\": false}, {\"check\": \"unknown caller country\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}