Fix billable messages warning

AGENTS.md

@@ -220,7 +220,7 @@ All output helpers use the `format` prefix and are exported from `src/utils/outp
 - **Limit warnings**: `formatLimitWarning(count, limit, "items")` — yellow warning if results truncated. Only show when `hasMore === true`.
 - **Pagination collection**: `collectPaginatedResults(firstPage, limit)` — walks cursor-based pages until `limit` items are collected. Returns `{ items, hasMore, pagesConsumed }`. Use for both SDK and HTTP paginated commands.
 - **Filtered pagination**: `collectFilteredPaginatedResults(firstPage, limit, filter, maxPages?)` — same as above but applies a client-side filter. Use for rooms/spaces list where channels need prefix filtering. `maxPages` (default: 20) prevents runaway requests.
-- **Pagination warning**: `formatPaginationLog(pagesConsumed, itemCount, isBillable?)` — shows "Fetched N pages" when `pagesConsumed > 1`. Pass `isBillable: true` for history commands (billable API calls). Guard with `!this.shouldOutputJson(flags)`.
+- **Pagination warning**: `formatPaginationLog(pagesConsumed, itemCount, isBillable?)` — shows "Fetched N pages" when `pagesConsumed > 1`. Pass `isBillable: true` for history commands (each message retrieved counts as a billable message). Guard with `!this.shouldOutputJson(flags)`.
 - **Pagination next hint**: `buildPaginationNext(hasMore, lastTimestamp?)` — returns `{ hint, start? }` for JSON output when `hasMore` is true. Pass `lastTimestamp` only for history commands (which have `--start`).
 - **JSON guard**: All human-readable output (progress, success, listening messages) must be wrapped in `if (!this.shouldOutputJson(flags))` so it doesn't pollute `--json` output. Only JSON payloads should be emitted when `--json` is active.
 - **JSON envelope**: Use `this.logJsonResult(data, flags)` for one-shot results, `this.logJsonEvent(data, flags)` for streaming events, and `this.logJsonStatus(status, message, flags)` for hold/status signals in long-running commands. The envelope adds top-level fields (`type`, `command`, `success?`). Nest domain data under a **domain key** (see "JSON data nesting convention" below). Do NOT add ad-hoc `success: true/false` — the envelope handles it. `--json` produces compact single-line output (NDJSON for streaming). `--pretty-json` is unchanged.

src/utils/pagination.ts

@@ -58,7 +58,7 @@ export function formatPaginationLog(
   const message = `Fetched ${pagesConsumed} pages to retrieve ${itemCount} results.`;
   if (isBillable) {
     return formatWarning(
-      `${message} Each page request counts as a billable message.`,
+      `${message} Each message retrieved counts as a billable message.`,
     );
   }