If a blue sentinel holds in a Startipped Peak, the player channel 2 runes exhausted or the blue sentinel, it doesn't trigger the hold effects of the battlefields?

To clarify the interaction between Blue Sentinel and Startipped Peak, here is how the mechanics function according to the game rules and established FAQs:

The Short Answer

Blue Sentinel does cause the hold effect of Startipped Peak to trigger an additional time, but it does not require you to exhaust an extra rune yourself. The ability of the Blue Sentinel simply makes your "hold effects" (the triggered abilities that happen because you are holding a battlefield) occur twice.

Explanation and Sequence

1. Triggering: At the beginning of your turn, because you are holding the battlefield Startipped Peak and have Blue Sentinel present, your hold effects trigger.
2. Blue Sentinel's Passive: Blue Sentinel's ability states: "Your hold effects for holding here trigger an additional time."
3. Hold Effects:
   • Startipped Peak has the ability: "When you hold here, you may channel 1 rune exhausted." Because of the Sentinel, this triggers twice.
   • Blue Sentinel itself has the ability: "When I hold, [Add] [A] at the start of your next Main Phase." Because of its own passive ability, this also triggers twice.
4. Chain Placement: Two instances of the Startipped Peak ability and two instances of the Blue Sentinel ability are placed on the chain.

Key Rules

• No Extra Exhaustion Required: Per RiftJudge FAQ #9539, Blue Sentinel does not force you to exhaust extra runes. When you resolve the triggers from Startipped Peak, you choose whether to exhaust 1 rune for each trigger (a total of 0, 1, or 2 runes).
• Triggered Abilities: As established in RiftJudge FAQ #10155 and #9697, passive modifiers like Blue Sentinel’s trigger all hold effects at that location, including the Sentinel’s own ability and the battlefield's ability, resulting in multiple triggers.

This interpretation is based on the card text of Blue Sentinel and Startipped Peak, and aligns with the existing rulings regarding Blue Sentinel’s interaction with hold effects.