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Espionage idea group.png Espionage
missing versioning

Embargo efficiency.png Privateers

+25% Embargo efficiency
+33% Privateer efficiency

Foreign spy detection.png Vetting

+25% National spy defense

May sabotage reputation.png Rumormongering

Allows sabotage reputation

Diplomat.png Efficient Spies

+1 Diplomats
+25% Spy offence

May study technology.png Shady Recruitment

Allows study technology
−33% Covert action relation impact

May sow discontent.png Destabilizing Efforts

Allows sow discontent
Allows agitate for liberty

May infiltrate administration.png Espionage

Allows infiltrate administration

Idea bonus.png Bonus:

+50% Rebel support efficiency

Associated events: Espionage idea group events

Espionage is a way to weaken enemies without actually going to war. In Europa Universalis 4 espionage works somewhat differently than EU3: there are no longer any spy agents, but covert actions are present. Rather than spies, diplomats perform espionage. Espionage has an associated idea group in the diplomatic group of ideas. This group unlocks several espionage actions, and makes espionage more powerful.

Spy efficiency

Discovery chance

The difference between the defending province's spy defence and the attacker's spy offence is applied additively to the yearly discovery chance, which has a base of 25%[1]. The monthly discovery chance is 1/12 of the yearly discovery chance. The discovery chance cannot be reduced below about 0.06% per month. After being discovered, a spy has a 5-year cooldown in which a nation can't send new spies to that country.[2] This doesn't apply to fabricating claims.

Spy defense

All spy defence is ultimately provincial, the total spy defence being the sum of the national spy defense and the local spy defense of that province. All spy actions other than Fabricate Claim use the spy defense of the capital. Each base tax Development level in a province adds Local spy defence.png+1% Local spy defense so consider prioritizing the capital's tax development if neighbouring countries take Espionage ideas.

National spy defense is modified by the following:

  • +5% per point of stability
  • -10% to +10% from Prestige
  • +25% from trading in Tobacco
Foreign spy detection.png Traditions Ideas Bonuses Policies
The modifier “national spy defense” was renamed with patch 1.16.

Local defense is modified by the following:

  • +1% per provincial base tax
  • -1% per local unrest

Spy offense

Spy Offense is modified by the following:

  • +20% if the target is a rival
  • +10% from trading in Spices
  • +10% from Diplomatic Spymaster Advisor
  • +5% from being the Emperor
  • +5% from being a Lucky nation

Spy network construction.png Traditions Ideas Bonuses Policies
The modifier “spy offense” was renamed with patch 1.16.

Covert actions

There's a number of new covert actions in EU4. The covert actions that have been revealed are listed below. Some actions are available to all nations while other require investment in the Espionage ideas. All spy discoveries, excluding fabrication of claims, have a 5-year cooldown timer before another spy can be sent to the target nation.

Fabricate claims

A claim on a province is an assertion that that province should be part of a nation. A diplomat can always be sent to fabricate a claim on a neighboring province or a province across a single sea zone. If the diplomat is discovered, nations in the area will get a base 5.0 aggressive expansion relations modifier; the agent can only be discovered once per fabricating claim.

The base time to fabricate a claim is one year[3]. This time can be affected by:

Ideas and policies:

Cost to fabricate claims.png Traditions Ideas Bonuses Policies
The modifier “time to fabricate claims” was renamed with patch 1.16.
Decisions and events:
Cost to fabricate claims.png Event modifier Trigger Duration
−10% Limited Claim Fabrication Diplomatic ideas event: “Incompetent Diplomats
Option: ‘They are of noble blood though...’
for 5 years.
  • Can't start fabrication on a country while at war with them. (fabrications started before the DoW, will complete normally)
  • Claims expire after 25 years. A claim can't expire during a war or truce with the country

Claiming colonies

'Inter Caetera' the third national idea of Spain/Castile allows the use of fabricate claim on colonies which normally wouldn't be in reach of that action. This allows Spain/Castile to target colonies both inland and distant overseas, making any colony in the world a potential target. (This special ability can no longer be used once the colony turns into a city at a population of 1000.)

Infiltrate administration

The nation needs to have unlocked the Espionage Ideas 7: 'Espionage' in order to perform this covert action. So long as one diplomat is present in the enemy capital, the fog of war is lifted over their country. As soon as the diplomat is discovered, he is sent home and the fog is returned.

Sow discontent

The nation needs to have unlocked the Espionage Ideas 6: 'Destabilising Efforts' in order to perform this covert action. A country can only be targeted by one Sow Discontent at a time, but multiple countries countries can be targeted by Sow Discontent, even if the player is at war with them.

The target suffers these maluses:[4]

Sabotage reputation

The nation needs to have unlocked the Espionage Ideas 3: 'Rumourmongering' in order to perform this covert action.

So long as one diplomat is present in the enemy country, all neighbours, enemies and rivals of the targeted country gets an opinion penalty of -50 towards the target. This will make it more difficult for the target to recover its reputation from recent expansions or betrayals, to make alliances and to enter other diplomatic agreements. A country can only have one sabotage on them at the same time.

Support rebels

Main article: Rebellion#Support rebels

A diplomat can always be sent to any nation where there is a province with an unrest greater than 0.

Study technology

The nation needs to have unlocked the Espionage Ideas 5: 'Shady Recruitment' in order to perform this covert action.

While a nation has a diplomat studying technology in another nation, it will receive +1 point of monarch power per month for each category (Diplomatic power.pngdiplomatic, Administrative power.pngadministrative, and Military power.pngmilitary) which it is at least two technologies behind the targeted nation. A maximum of 1 point of each type can be gained per month, regardless of how many diplomats a nation has performing this action.

Agitate for liberty

The nation needs to have unlocked the Espionage Ideas 6: 'Destabilising Efforts' in order to perform this covert action. Can only be used on subject nations, and each subject nation can be a target of only one agitate for liberty at a time.

As long as a diplomat is present and performing this action, the target's Liberty desire.pngliberty desire will tick up every month, up to a maximum of +25%. If the diplomat is discovered or recalled, this will then tick back down to zero, rather than being instantly removed.


  1. See in /Europa Universalis IV/common/defines.lua: BASE_SPY_DISCOVERY_CHANCE = 0.25,
  2. See in /Europa Universalis IV/common/defines.lua: SPY_DISCOVERY_COOLDOWN_MONTHS = 60,
  3. See in /Europa Universalis IV/common/defines.lua: DAYS_TO_FABRICATE_CLAIM = 365, -- DAYS_TO_FABRICATE_CLAIM
  4. See in /Europa Universalis IV/common/static_modifiers/00_static_modifiers.txt (Static modifiers#Discontent).