Flag a DonorPerfect donor segment accurately in one pass

**Objective:** Apply the flag `{flag}` to donors matching `{selection-criteria}`, for example donors in a given state who have given at least a certain amount. Build the list, show it, and only then write.

**Step 1: Validate the flag**

Call `donorperfect-get-code` filtered on the flag field and confirm `{flag}` exists. If it does not, list the valid flags and stop. Never create a flag value by writing one.

**Step 2: Build the selection**

Read `{selection-criteria}` and translate it into filters on `donorperfect-get-donor`. Only the following are available: `donor-type`, `gift-total.min`, `last-name`, `last-name.contains`, `first-name.contains`, `email`, `city`, `state`, `donor-id`, `max-records`.

If the criteria need something not on that list, such as a gift date range, pull the candidates with the filters that do exist and then narrow them with `donorperfect-get-gift` filtered by each `donor-id`. Say which part of the criteria you handled in which step.

If the criteria cannot be expressed at all, say which part is impossible and stop.

**Step 3: Remove donors who already carry the flag**

For each candidate, call `donorperfect-get-flag` filtered by `donor-id`. Drop anyone who already has `{flag}` and report how many you dropped.

**Step 4: Confirm the whole list**

Show the final list as a table: donor name, donor id, and the values that qualified them. State the count plainly, for example "this will flag 34 donors". Ask the user to confirm the list before any write.

**Step 5: Write**

Only after the user confirms, call `donorperfect-set-flag` once per donor on the confirmed list, and no others. Report progress as you go and stop immediately if a call fails, saying how many were flagged before the failure.

**Step 6: Verify**

Spot check by calling `donorperfect-get-flag` filtered by `flag` and confirm the count went up as expected.

**Rules & Guidelines:**

* `donorperfect-set-flag` is the only write tool this prompt may call. Do not call `donorperfect-save-donor` to change anything else about a donor.
* Never flag a donor who was not on the confirmed list.
* If the list exceeds 50 donors, say so and ask the user to confirm again before writing, since there is no bulk unflag tool to undo it.

**Validation:**

* If the selection returns nothing, say so and write nothing.
* If the user confirms only part of the list, write only that part.