extension-data-viewer

Original：🇺🇸 English

Translated

Admin-only paginated viewer for stable canister state. Use whenever the user asks for a viewer, dashboard, debug panel, or admin browse over backend data — users, items, orders, logs, or any stable Map/Set/Array/VarArray/List/Stack/Queue. Pre-installed in every Caffeine app via the `caffeineai-data-viewer` mops package; this skill explains what it does and how to keep using it correctly.

233installs

Sourcecaffeinelabs/skills

Added on2026-06-18

NPX Install

npx skill4agent add caffeinelabs/skills extension-data-viewer

SKILL.md Content

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Data Viewer

Admin-only data inspection extension for Caffeine AI.

Overview

Every Caffeine app ships with the

caffeineai-data-viewer

mops package and the moc

--generate-view-queries

flag enabled. Together with

include MixinViews()

in the actor, the compiler auto-exposes a controller-only
__<var>
query for every stable variable of a supported type:

```
Map.Map<K, V>
```
—
```
(?K, ?Nat) -> [(K, V)]
```
```
Set.Set<K>
```
—
```
(?K, ?Nat) -> [K]
```

[V]

,

[var V]

,

List.List<V>

,

Stack.Stack<V>

,

Queue.Queue<V>

—

(?Nat, ?Nat) -> [V]

A

null

cursor starts at the beginning; a

null

count returns everything from the cursor. Each generated query traps on any non-controller caller — they exist for admin dashboards and debug viewers, not user-facing endpoints.

Backend

The package and

include

are already wired into the template. You don't need to add or edit anything for the viewer to work — declare a stable variable of a supported type and the

__<var>

query appears automatically.

motoko

import Map "mo:core/Map";
import Principal "mo:core/Principal";
import MixinViews "mo:caffeineai-data-viewer/MixinViews";

actor {
  include MixinViews();

  let users = Map.empty<Principal, Text>();

  // Generated automatically: __users : (ko : ?Principal, count : ?Nat) -> [(Principal, Text)] query
};

Lintoko rule

include-mixin-views

(shipped with the package) errors if the actor body is missing

include MixinViews();

. Keep the include — removing it disables every auto-generated viewer.

Rules

NEVER use the generated
```
__<var>
```
queries as a substitute for user-facing endpoints — they trap for any non-controller caller. Public list/feed/search methods still need to be written normally with
```
public query func listX(...)
```
.
NEVER declare an actor member whose name starts with
```
__
```
— it either collides with an auto-generated query or hits a reserved prefix.
Pure (immutable) collections (
```
pure/Map
```
,
```
pure/Set
```
,
```
pure/List
```
,
```
pure/Queue
```
) are not supported. The viewer is mutable-only by design; pure collection field access is a deprecated pattern in Caffeine projects anyway.