Define custom Temporal Search Attributes and query workflow executions using List Filters

Documented steps

1. Create a custom Search Attribute: `temporal operator search-attribute create --name YourAttributeName --type Keyword`. Accepted `--type` values are Text, Keyword, Int, Double, Bool, Datetime, and KeywordList.
2. List registered attributes for the namespace: `temporal operator search-attribute list`.
3. Set attributes at workflow start in Python: `client.start_workflow(..., search_attributes=TypedSearchAttributes([SearchAttributePair(customer_id_key, "value")]))` where `customer_id_key = SearchAttributeKey.for_keyword("CustomerId")`. Other factories: `for_text`, `for_int`, `for_double`, `for_bool`, `for_datetime`, `for_keyword_list`.
4. Set attributes at workflow start in TypeScript: `client.workflow.start(example, { taskQueue, workflowId, searchAttributes: { CustomIntField: [2], CustomKeywordListField: ['a','b'], CustomBoolField: [true], CustomDatetimeField: [new Date()] } })` — values are always arrays typed by attribute.
5. Update attributes from inside a running workflow — Python: `workflow.upsert_search_attributes([customer_id_key.value_set("customer_2")])`, and remove one with `customer_id_key.value_unset()`. TypeScript: call `upsertSearchAttributes(...)` from workflow code and read current values via `workflowInfo().searchAttributes`.
6. Query with a List Filter from the CLI: `temporal workflow list --query 'WorkflowType = "YourWorkflow" and ExecutionStatus != "Running"'`, or `temporal workflow count --query '...'` when you only need a count.
7. Use the documented List Filter operators: `=, !=, >, >=, <, <=`, `AND`/`OR` with parentheses, `BETWEEN ... AND`, `IN (...)`, and `STARTS_WITH`. Example: `ExecutionTime between '2021-08-22T15:04:05+00:00' and '2021-08-28T15:04:05+00:00'`.
8. Account for Text versus Keyword semantics: Text attributes tokenize on Unicode word boundaries and match word by word, while Keyword attributes require an exact match or `STARTS_WITH` for prefix matching.
9. Query programmatically by passing the same List Filter string to the SDK's list-workflows call, e.g. TypeScript `WorkflowService.listWorkflowExecutions` with `query: 'ExecutionStatus = "Running"'`.
10. Remove an unused custom attribute with `temporal operator search-attribute remove --name YourAttributeName [--yes]`. On Temporal Cloud the docs direct you to contact support instead of self-service removal.
11. Reference docs: https://docs.temporal.io/search-attribute | https://docs.temporal.io/list-filter | https://docs.temporal.io/cli/command-reference/workflow