[{"code":"invalid-input","category":"invalid_input","summary":"The provided request or payload shape is invalid.","why":"The caller supplied malformed JSON, a missing required field, or an unexpected value shape for the requested operation.","recovery":"Inspect the relevant input schema and local help for the targeted operation, then resend a valid request.","related_help_operation_ids":["validate-scenario","get-schema"]},{"code":"unknown-operation","category":"unsupported","summary":"The requested operation is not part of the public solver contract.","why":"The caller referenced an operation ID or affordance name that is not registered in the shared contracts graph.","recovery":"Start from bootstrap help, then choose one of the registered top-level operations.","related_help_operation_ids":["solve","validate-scenario","get-schema"]},{"code":"unknown-schema","category":"unsupported","summary":"The requested schema ID is not registered.","why":"The caller requested a schema identifier that does not exist in the contract registry.","recovery":"Inspect the schema lookup/help affordance and request one of the registered schema IDs.","related_help_operation_ids":["get-schema"]},{"code":"unknown-error-code","category":"unsupported","summary":"The requested public error code is not registered.","why":"The caller requested an error code identifier that does not exist in the contract registry.","recovery":"Inspect the error-catalog help affordance and request one of the registered public error codes.","related_help_operation_ids":["inspect-errors"]},{"code":"infeasible-scenario","category":"infeasible","summary":"The scenario definition is internally inconsistent or infeasible.","why":"The solver cannot satisfy the required constraints, capacities, or session assignments for the provided scenario input.","recovery":"Validate the scenario, inspect constraint settings, and adjust the input so a valid schedule is possible.","related_help_operation_ids":["validate-scenario","solve"]},{"code":"unsupported-constraint-kind","category":"unsupported","summary":"A constraint kind or similar enum-like value is not supported.","why":"The caller referenced a named domain feature that is not part of the currently supported public contract.","recovery":"Inspect the relevant schema and contract help, then replace the unsupported value with a supported one.","related_help_operation_ids":["validate-scenario","get-schema"]},{"code":"quota-exceeded","category":"permission","summary":"An anonymous free quota or rate limit is exhausted for the current window.","why":"The hosted public API uses per-client/IP request, solve-time, and active-solve guards plus global backstops to keep the free service available without accounts.","recovery":"Retry after the advertised reset/retry interval, reduce solve cost, or use a local/private GroupMixer surface for larger workloads.","related_help_operation_ids":["auto-solve","inspect-errors"]},{"code":"request-too-large","category":"invalid_input","summary":"The request body exceeds the hosted public API payload limit.","why":"The hosted public API caps payload bytes before parsing to protect the anonymous free service from excessive memory and bandwidth use.","recovery":"Send a smaller scenario payload or use a local/private GroupMixer surface for larger workloads.","related_help_operation_ids":["auto-solve","get-schema"]},{"code":"unsupported-public-field","category":"unsupported","summary":"The request includes a field that is intentionally unsupported by the hosted public API.","why":"The hosted public API exposes only automatic solving and does not accept solver configuration, solver-family selection, warm starts, or stop-condition controls.","recovery":"Remove the unsupported field and let the public auto policy choose the solver configuration, or use a local/private surface for advanced control.","related_help_operation_ids":["auto-solve","get-schema"]},{"code":"internal-error","category":"internal","summary":"An unexpected internal failure occurred.","why":"The operation failed for a reason outside the normal public validation and feasibility model.","recovery":"Capture the error details, inspect local help for the attempted operation, and retry only if the failure is known to be transient.","related_help_operation_ids":["solve","validate-scenario","inspect-result","inspect-errors"]}]