Calculate over a selected capture

Check a catalog total without disclosing its rows

Use an enrolled client, an inspected response from your own test app, and a complete retained JSON body. For a small test, use a response shaped like {"items":[{"price":0.1},{"price":0.2}]}. The question is whether those two captured prices sum to 0.3, not whether checkout charged that amount.

1. Find the catalog request in Table. Copy its session ID and confirm that this response contains the collection you intend to measure.
2. Ask for capture_calculate over MCP or use capture calculate in the CLI. Select the responseJSON dataset and /items collection. Choose numericSummary and the row-relative field /price. Review the sensitive-read grant locally.
3. Check the status before the number. In the synthetic integration test for these two rows, the result was complete with a sum of "0.3". Removing the retained body produced unavailable with a null result, not a zero total. The calculation does not refetch the response.

Pick the operation that answers your question

Operation	Example question
rowCount	How many rows are in the selected collection?
fieldStats	Is artwork missing, explicitly null, or a string?
distinctCount	How many distinct non-null scalar identifiers are present?
groupCount	Among these selected sessions, how many had each HTTP status?
numericSummary	What is the sum or range of a numeric price field?
topRows	Which rows have the largest numeric values? Get references instead of entire rows.

For the status question, choose explicit session IDs, the sessionMetadata dataset and /statusCode. The result describes those sessions, not every request on the network. For a JSON field with mixed types, start with fieldStats; a price encoded as a string isn’t a decimal operand. These operations are bounded calculations, not a way to run arbitrary code.

Verify and finish

For a small fixture, independently count the selected rows or add the known inputs. If the selection is stale, select the fresh session explicitly; never combine numbers from different revisions as though they came from one response. The read creates no rewrite to undo. Review any temporary access you granted when you finish.