Stop Hand-Rolling Parallel Arrays: LotusScript's List Is the Built-In HashMap for Counting, Dedup, and Lookups

You need to count documents by category, dedup a set of names, or build a code-to-label lookup. The Domino reflex is two parallel arrays and a linear scan, or a throwaway view. But LotusScript has had a native keyed collection all along and almost nobody reaches for it: the List. A field report on the built-in associative array — its keyed access, ForAll + ListTag iteration, Erase, and the two gotchas (guarding reads with IsElement, and tag case sensitivity following Option Compare).

Field Notes from OpenNTF's Domino IQ RAG Webinar: the 30-Char Gotcha, Vectorization in 3 Steps, and the FP1 Readers Fix

OpenNTF hosted HCL's Brian Arnold for a deep session on Domino IQ RAG. We've already covered how the pipeline works under the hood; this is the field-report layer — the 30-character limit for RAG-enabling short fields and the concat-field way around it, vectorization in three steps, the three knobs to tune, the fact that Readers/Authors-field security only really started working in Domino 2026 FP1, and the citations, side panel, and MCP still under development.

@DbLookup and @DbColumn: the Cache Keyword You're Not Passing, and the 64K Wall

You update a keyword document, reload the form, and the dropdown still shows the old value. Or a keyword list quietly stops growing at a few thousand entries. Both are @DbLookup / @DbColumn behaviours hiding in the argument most formulas leave empty: the cache keyword. A field report on the three cache options (default / NoCache / ReCache) and the hard 64KB limit on what these functions can return — with the classic-web cases where each one bites.

Who Does Your Agent Run As? Signer, Effective User, and the Error 201 / Readers-Field Traps

Your agent works perfectly when you run it — because you're the admin who signed it. Deploy it as a web agent, or schedule it signed by a service ID, and it fails with Error 201 or silently sees no documents. The cause is identity: a Domino agent runs as someone, and that someone isn't always you. A field report on the signer vs the effective user, how session.EffectiveUserName flips on 'run as web user', the runtime security level behind Error 201, and the Readers-field trap that makes documents vanish.

NotesUIScheduler: Driving the Embedded Free/Busy Grid From LotusScript

A custom room-booking or meeting form has the embedded scheduler control — the busy-time grid where you add attendees and see everyone's free/busy. NotesUIScheduler is how you drive that control from code: get it by name off the UI document, add or remove participants, refresh the schedule data, and read back the interval the user picked. A field report on the one front-end scheduling class, its GetScheduleData refresh, and the two events you hook.

Button, Field, Navigator: the LotusScript Classes With Zero Properties and Zero Methods

Open the LotusScript help for Button and you expect properties and methods — there are none. Same for Field, same for Navigator. All three are empty on purpose: they exist only as event entry points, the typed Source parameter that tells a front-end event handler which element fired it. A field report on the three classes you never call anything on — what their events are (Click, Entering / Exiting / OnChange), and why the real work always goes through NotesUIDocument.

The LotusScript Web Agent I/O Model: Print Is Your Response, DocumentContext Is Your Request

A LotusScript web agent has no request object and no response object — it has Print, whose output becomes the HTTP body, and DocumentContext, a special document holding the CGI variables. A field report on the two halves: how the first Print line sets Content-Type so you can return JSON instead of HTML, how to read the query string and POST body from DocumentContext, the CGI-fields gotcha that leaves them empty, and how it all fits with a top-level error handler.

DXL Round-Trip Pitfalls: Why Export-Then-Import Gives You Duplicates, Not the Same Documents

You export documents to DXL, import the DXL into another database, and end up with copies carrying brand-new UNIDs instead of the same documents updated in place — because the importer creates by default and only matches on UNID when you tell it to. A field report on the DXL round-trip: the DocumentImportOption that decides create-vs-replace, why default rich text isn't binary-identical (and when to switch to RAW), and the stale-handle trap that hides the whole thing.

LotusScript Error Handling: On Error Is Per-Procedure, and Resume Next Is Not 'Ignore Errors'

Two habits sink most LotusScript error handling: treating On Error as if it were global (it's per-procedure, and uncaught errors climb the call stack), and reaching for On Error Resume Next as a blanket 'ignore errors' switch (it hides the bug, it doesn't handle it). A field report on doing it deliberately — the per-procedure scope, the Err / Error$ / Erl lifecycle, the difference between Resume, Resume Next, and Resume label, and the clean-error pattern a web agent actually needs.