effect · add_claim_by

Hands-On Usage

add_claim_by is commonly used in territorial expansion mods. When a nation fulfills specific conditions through events, decisions, or focuses, it dynamically adds claims to a state, enabling subsequent diplomatic pressure or war justifications. For example, in a "Renaissance Empire" scenario, when the player completes a certain national focus, claims are batch-added to historical territory states:

# Execute under STATE scope, e.g., iterating over specific state groups
add_claim_by = ROOT

It can also be paired with every_neighbor_state to batch-process adjacent states, allowing a nation to claim all neighboring states at once—ideal for constructing dynamic logic around sphere of influence expansion.

Synergy

• [is_claimed_by](/wiki/trigger/is_claimed_by): Before adding a claim, first check whether the state is already claimed by the target nation to avoid redundant trigger logic or event firing.
• [remove_claim_by](/wiki/effect/remove_claim_by): The complementary removal command, commonly used in peace settlement or treaty events to remove previously added claims, forming a complete claim lifecycle management system.
• [add_core_of](/wiki/effect/add_core_of): Claims are often a prerequisite step to cores; combining both simulates the historical process of "claiming first, then annexing to form a core."
• [is_core_of](/wiki/trigger/is_core_of): Determines whether a target state is already a core, allowing the logic to add only a claim rather than redundantly appending a core, keeping conditional branching clear.

Common Pitfalls

1. Scope confusion: add_claim_by must be executed under STATE scope; the target parameter specifies the nation tag or scope keyword making the claim. Beginners often mistakenly place it under COUNTRY scope, causing parse errors or silent failures. Always switch to the correct scope first using every_state/state or similar constructs.
2. Passing a state instead of a nation as target: The effect's parameter is the claiming nation (e.g., GER, ROOT), not a state ID. Filling in a state ID is a common mistake. The correct approach is: call the effect within the state's scope (that's which state gets claimed), and only specify the parameter as "which nation" is doing the claiming.