[Bug] Anthropic API Error: Invalid JSON Schema in Tool Definition

Bug Description
API Error: 400 tools.17.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://platform.claude.com/docs/en/agents-and-tools/tool-use/overview.

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.232
• Feedback ID: 3cefa5fb-c9a2-4809-82b2-64f32f6ec192

Errors

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"tools.17.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://platform.claude.com/docs/en/agents-and-tools/tool-use/overview.\"},\"request_id\":\"req_011Ce2ZWqbB1mTx8WWqB4D8k\"}\n    at generate (/$bunfs/root/cli:39:39014)\n    at makeRequest (/$bunfs/root/cli:90:8063)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-08-14T11:27:56.663Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"tools.17.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://platform.claude.com/docs/en/agents-and-tools/tool-use/overview.\"},\"request_id\":\"req_011Ce2ZX8d7Et2Er1ZECfT5j\"}\n    at generate (/$bunfs/root/cli:39:39014)\n    at makeRequest (/$bunfs/root/cli:90:8063)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-08-14T11:28:00.691Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"tools.17.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://platform.claude.com/docs/en/agents-and-tools/tool-use/overview.\"},\"request_id\":\"req_011Ce2ZczMw7tw2KnPBz9XDn\"}\n    at generate (/$bunfs/root/cli:39:39014)\n    at makeRequest (/$bunfs/root/cli:90:8063)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-08-14T11:29:20.202Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"tools.17.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://platform.claude.com/docs/en/agents-and-tools/tool-use/overview.\"},\"request_id\":\"req_011Ce2Zesr5UUKo7XJhCHzqz\"}\n    at generate (/$bunfs/root/cli:39:39014)\n    at makeRequest (/$bunfs/root/cli:90:8063)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-08-14T11:29:45.702Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"tools.17.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://platform.claude.com/docs/en/agents-and-tools/tool-use/overview.\"},\"request_id\":\"req_011Ce2ZgSepSVQVzwGg1ynST\"}\n    at generate (/$bunfs/root/cli:39:39014)\n    at makeRequest (/$bunfs/root/cli:90:8063)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-08-14T11:30:06.911Z"}]