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This article has been verified for the current PC version (3.6) of the game.
Diplomacy between plantoids and arthropoids

Diplomacy in Stellaris draws on the model of previous Paradox games and offers an alternative to warmongering.


Envoys are minor leaders that can be assigned to perform various diplomatic tasks. Once an envoy is assigned to a task, it cannot be reassigned again for a year. Envoys can be assigned to the following tasks:

  • Improve Relations with another empire, which grants   +0.25 opinion per month to and from the target empire (up to +100) and removes the relation requirement for positive diplomatic actions
  • Harm Relations with another empire, which grants   −0.5 opinion per month to and from the target empire (up to −100) and removes the relation requirement for negative diplomatic actions
  • Assign to the Federation, which grants   +1 cohesion per month to the federation
  • Assign to the Galactic Community, which grants   +10% diplomatic weight
  • Assign to the Galactic Imperium, to either strengthen or weaken Imperial Authority
  • Assign to a first contact, and they will investigate and discover the aliens for you
  • Assign to build a Spy Network, which will increase   infiltration in another empire over time. With an active Spy Network, Operations can be carried out.

Each Empire starts with 2 Envoys by default and can gain additional ones in the following ways:

Source Available envoys
  Fanatic Xenophile ethic +2
  Diplomatic Corps civic +2
  Pompous Purists civic +2
  Empath civic +2
  Public Relations Specialists civic +2
  Shared Destiny ascension perk +2
  Grand Embassy Complex building +2
  Orbital Embassy Complex orbital ring building +2
  Interstellar Assembly (stage IV) +2
  Xenophile ethic +1
  Delegated Functions civic +1
  Galactic Sovereign civic +1
  Corporate Sovereign civic +1
  Embassy Complex building +1
  Sanctum of the Whisperers building +1
  Bureau of Espionage edict +1
  Observation Instinct edict +1
  Covert Analysis Algorithm edict +1
  Diplomatic Grants edict +1
  Enhanced Surveillance edict +1
  Politics tradition tree +1
  Diplomacy tradition tree finish +1
  The Federation tradition +1
  Universal Compatibility tradition +1
  Double Agents tradition +1
  Autonomous Agents technology +1
  Embodied Dynamism technology +1
  Courtly Knights Knightly Duties policy +1
  Interstellar Assembly (stage II) +1
  Inward Perfection civic −1

Diplomatic actionsEdit

Many diplomatic actions have a 10-year cooldown once chosen. Some of these are unilateral while others need to be accepted by both sides which becomes a matter of acceptance. Most diplomatic actions require certain a Relations level or an envoy being sent to improve or harm relations.

Maintaining any form of lasting treaty generates   Trust, which increases   opinion. The maximum amount of Trust obtainable is limited by the most valuable treaty between both parties. Acquiring the Direct Diplomacy perk from the   Diplomacy tradition tree grants   +50 trust cap. Trust decays if there is no new income (i.e. no ongoing treaty that generates trust).

Action Effects         Relations Requirements Limit    
  Improve Relations Sends an   Envoy to increase   Opinion up to +150 0 0 50 0 Any    Harming Relations N/A  
  Harm Relations Sends an   Envoy to lower   Opinion up to −150 0 0 50 0 Any    Improving Relations N/A  
  Build Spy Network Sends an   Envoy to build a Spy Network 0 0 50 0 Any   Spy Network N/A
  Make Claims Switches to the Claims interface. 0 0 0 0 Any Can claim any system N/A
  Declare War Enters the Wargoals menu to declare a war −50 0 50 0 Any
  •    Truce, pact, or federation with target
  •    Branch office on target's planets
  Close/Open Borders Controls border access. The initial stance is determined by the Initial Border Status policy. −20 0 50 0 Any
  •    Truce
  •    Rivalry
  • Not available between overlords and subjects
  Invite to Federation Invites the target empire to join a Federation. Other Federation members must agree. +50 +1 100 −2 Excellent
  •   Federation member
  • Both empires at peace
  Ask to join Federation Requests to join an already existing Federation. Other Federation members must agree. +50 +1 100 −2 Excellent
  • Target is part of a   Federation
  • Both empires at peace
  Kick from Federation Starts a vote to kick the member from the Federation 0 0 50 0 Any
  • Member of the same Federation
  • At peace
  Ask to leave Federation Requests to leave the Federation. Refusing grants the Secession Casus Belli and a decaying −45   Opinion. 0 0 50 0 Any
  •   Hegemony Federation
  • At peace
  • Target is the Federation president
  Association Status The empire and the Federation will not be able to declare war upon each other. +10 +0.50 100 0
  • Positive
  • Excellent
The majority of federation members must agree to granting or removing the status but the associate member can cancel it at any time N/A  
  Propose Subjugation Enters the Terms menu to propose becoming overlord +25 +0.25 50 0 Any Both empires at peace N/A    
  Ask to be their Subject Enters the Terms menu to propose becoming subject +25 +0.25 50 0 Any Both empires at peace 1  
  Release Subject Grants independence to the subject and sets a 10-year Truce 0 0 50 0 Any N/A  
  Integrate Subject Integrates a Vassal or Protectorate into the overlord empire. 0 0 50 Variable Any
  • Integration Permitted term of agreement
  • Sufficient   Influence
  Insult Decaying −200   Opinion Modifier 0 0 50 0
  • Terrible
  • Tense
  Add to/Kick from Imperial Council Decides who is member of the Imperial Council. 0 0 50 0 Any
  • 100   influence
  • Galactic Emperor
  • By Appointment Imperial Council resolution
  • Target is a member of the Galactic Imperium

Unilateral agreementsEdit

Unilateral agreements are diplomatic actions that are only proposed and ended by one of the empires, with no input from the recipient. Rivalries can only end 10 years after they were proposed.

Agreement Effects Relations   Truce if ended           Limit Target independence
  Rivalry Closes borders and grants the Animosity Casus Belli
Reduces claim cost by 20%
  −100 0 50 +0.5   3 Independent
  Guarantee Independence The guaranteeing empire will join the target's defensive wars Neutral
  +10 +2.5 50 −0.25   3 Independent
  Support Independence The supporting empire will join the war against the overlord if the subject starts a war for independence
The supporting empire's power will be added to the relative power of subjects opinion modifier between the subject and the overlord
Any   0 0 50 0   N/A Subject
  Secret Fealty The target empire gains the Allegiance War casus belli Any   0 0 50 0   N/A Subject

Bilateral agreementsEdit

Bilateral agreements are mutually-beneficial diplomatic actions that when offered by an empire must also be accepted by the recipient in order for them to take effect. Agreements can be ended at any time by either empire but doing so will cause a temporary   Opinion penalty. Defensive Pacts and Federations can only be made or broken when neither empire is at war with anyone. Federations also require the   The Federation tradition.

Agreement Effects Min Relations   Truce if ended   Opinion if ended                    
  Embassy Envoys improve relations 3 time faster
Diplomatic pacts give 20 more   Intel
Neutral   0 0 +0.75 100 0 0          
  Non-Aggression Pact Neither empire can declare war upon each other Neutral   −50 0 +0.50 75 20 −0.25          
  Research Agreement +25%   Research Speed for technologies discovered by the other empire Positive   −25 0 +0.10 50 30 −0.25          
  Commercial Pact Both empires will gain the economic bonuses of 10% of each other's   Trade Value Positive   −25 0 +0.25 50 20 −0.25          
  Migration Treaty Pops can migrate between the empires and both empires can use each other's Pops in colony ships Positive   −15 0 +0.25 50 30 −0.25          
  Defensive Pact If either empire is attacked the other will join the war as a defender Excellent   −100 20 +0.75 100 40 −1          
  Federation Neither empire can declare war upon each other
If either empire is attacked the other will join the war as a defender
Additional effects based on Federation type and laws
Excellent   −200 50 +1 100 70 −0.5          


The acceptance of diplomatic agreements by computer empires is determined by multiple factors.

Agreement Friendly Attitude Receptive / Cordial / Protective Attitude Neutral / Wary Attitude Overwhelming Relative Power Superior Relative Power Shared Rival Opinion Distance Other factors
  Embassy +100 +40 −25 +20 +10 +30 per Rival +5 per 10 Opinion −0.5 per hyperlane
  Non-Aggression Pact +100 +20 0 +100 +50 +50 per Rival +2 per 10 Opinion −1 per hyperlane −30 per existing Non-Aggression Pact
  Commercial Pact +100 +20 0 0 0 0 +4 per 10 Opinion −1 per hyperlane +1 per given Trade Value
−30 per existing Commercial Pact
  Research Agreement +100 +20 0 0 0 0 +4 per 10 Opinion −1 per hyperlane +1 per tech either empire doesn't have
−30 per existing Research Agreement
  Migration Treaty +10 0 0 0 0 0 +5 per 10 Opinion −1 per hyperlane +10 Loyal Attitude
  Defensive Pact +50 +20 −50 +20 +10 +30 per Rival +2 per 10 Opinion −1 per hyperlane +30 per shared Defensive Pact
−50 per existing Defensive Pact
  Federation +30 0 −50 +20 +10 +10 per Rival +1 per 10 Opinion −1 per hyperlane +100 Federation Associate
+30 Crisis
−50 Different War Philosophy policy
  Subject Demand +20 0 −50 +100 +50 0 0 −5 per hyperlane −1 per 4 owned Pops


The most specific factor that determines an empire's acceptance rate is its AI personality.

AI personality Agreement Federation   Trade Willingness
Decadent Hierarchy +20 −10 0 0 −100 −30 −30 −30 −30 −30 −10 90%
Democratic Crusaders 0 +20 0 0 0 +10 0 +10 0 0 −50 90%
Erudite Explorers +5 +5 +50 +10 0 0 0 0 +10 −10 0 90%
Evangelizing Zealots 0 0 −20 −20 0 −20 −20 −10 −20 +20 −20 75%
Federation Builders +25 +25 +15 +15 +10 +20 +10 +10 +10 +10 +10 95%
Harmonious Collective +20 0 +10 +10 −10 0 0 0 0 0 0 90%
Hegemonic Imperialists −10 +10 −10 −10 −50 −20 −20 −10 −20 −20 0 80%
Honorbound Warriors −100 +20 0 −20 0 −10 −20 0 −20 −20 −10 70%
Migratory Flock +20 0 +20 +20 +100 +20 +20 +10 +20 −20 +10 110%
Peaceful Traders +20 0 +10 +20 +20 +10 +20 −10 +10 −10 +10 100%
Ruthless Capitalists −10 0 +10 +20 0 −10 +10 −10 −10 −10 −10 100%
Slaving Despots −20 0 0 0 −100 −10 −10 −10 −10 −10 0 80%
Spiritual Seekers +20 +10 +10 +10 +20 +10 +10 +10 −10 +10 +10 90%
Xenophobic Isolationists +20 −20 −20 −20 −100 −50 −50 −50 −50 −50 −50 50%
Fanatical Befrienders +50 +50 +50 +50 +50 +50 +30 +30 +30 +30 +30 100%
Fanatical Purifiers 0 0 0 0 0             50%
Hive Mind −10 −10 0     −50 −100 −30 −50 −50 −50 70%
Machine Intelligence 0 0 0     −30 −100 −20 −20 −100 −30 80%
Rogue Servitors 0 0 0     0 0 0 0 −100 +10 90%
Driven Assimilators 0 0 0     −50 −50 −50 −50 −100 −50 50%
Determined Exterminators 0 0 0                 100%
Crisis Aspirant 0 0 0 0 0 0 0 0 0 0 0 50%
Indolent Overlord 0 0 0 0 0 0 0 0 0 0 0 25%

Trade dealsEdit

Trade deals are instant or monthly transfers of resources or other assets between two empires. Deals that transfer monthly resources last between 10 and 30 years; once the AI fills their stockpile, long-term contracts become only viable option. It is possible to break long-term trade contracts if not enough resources are stockpiled, but this causes an   opinion penalty. Diplomatic trades often can yield better deals than the market. The AI will never accept mixed long-term/instant trades. Although   Gestalt Consciousness empires have no use for   consumer goods or   Zro, they are still willing to trade for them.

Trading requires a neutral or positive attitude between the two empires. Empires holding a negative attitude will accept only gifts (giving them resources without them giving anything in return). Fallen empires only trade if they are patronizing or enigmatic towards the proposing empire and will never trade strategic resources. Resources cannot be traded between overlords and subjects if the terms of agreement include contribution or subsidies in that resource.

  Trade willingness shows how much an empire is open to trading with other empires and is dependent on their AI personality. The lower their trade willingness is, the more favorable a trade deal has to be for them to see it as fair. Empires with less than 75% trade willingness will never make offers.

In addition to resources, the following things can be traded diplomatically:

  •   Favors: Each favor has a trade acceptance of 100, raised or lowered by the AI empire's trade willingness.
  •   Communications: Valued based on the number of new contacts. Does not include Enclaves. Fallen Empires always refuse.
  •   Active Sensor Link: Valued based on distance, neighboring empires being more interested. Allows the empire receiving the link to see everything the granting empire can see. Only available as a timed deal. Fallen Empire always refuse.
  •   Transfer System: Available only towards neighbors during peacetime, it is the most valued trade option and can be used to offer to cede one of your star systems, usually non-preferred planets that are too expensive to terraform or adapt pops to, or as a way to ease opinion penalty of claims or border tension. The AI will always refuse to accept systems that contain colonized Holy Worlds or border the Militant Isolationists.

Subject trade dealsEdit

Subject empires have additional trading options with their overlord:

  •   Borrow Fleet: Gives the subject temporary control a fleet. Valued based on how much of the total fleet power the fleets represent.
  •   Pledge Loyalty: Only available from a subject towards the overlord as a timed trade deal; if the subject has   150 opinion or better towards the overlord, it gives   +2.5 loyalty monthly, otherwise +1.5 monthly.
  •   Share Empire Data: Adds   +20 intel from the giver to the recipient; can be given by the overlord if they have 80 or less intel on the subject; can be given by the subject if they have 40 or less intel on the overlord.
  •   Loyalty: Only available from a subject towards its overlord, each point of loyalty will increase trade acceptance by 1. Loyalty can be used even if the value would become negative, up to −100.
  •   Transfer Leader: Requires a tier 2 specialized subject, transfers a subject leader to the overlord. Valued based on the leader's abilities.

Specialist subjects have additional, unique trade options which extend their bonuses to the overlord, usually at the cost of their own:

Type Trade   Timed Effect Overlord Subject Multiplied by Tier
  Bulwark Bulwark Prefabs     Defense Platform
  •   Build cost

  •   Upkeep
−25% +25%  
Bulwark Technology  
  • Researched Bulwark technologies given as options to Overlord

  • Subject gets Bulwark Technology Sharing modifier for   1 year:
    • Reduces shared technologies'   type(s) production by −10%
  Prospectorium Prospectorium Techniques       Monthly strategic resources +5% −5%  
Prospectorium Technology  
  • Researched Prospectorium technologies given as options to Overlord

  • Subject gets Prospectorium Technology Sharing modifier for   1 year:
    • Reduces shared technologies'   type(s) production by −10%
  • Subject pays   100 strategic resources by technology shared
  Scholarium Scholarium Processors     Research station output
  • +10%

  • +10%
  • −5%

  • −5%

Scholarium Hypotheses     Research alternatives +1 −1  

Trade acceptanceEdit

The trade acceptance number shows how much the other empire favors a deal. A trade acceptance lower than 1 means that the other empire sees the deal as disadvantageous for them and will always refuse it. A trade acceptance of 1 means that AI empire sees the deal as fair and will always accept it. A trade acceptance higher than 1 means that the other empire sees the deal as advantageous for them and will give a temporary bonus to their   opinion, up to a limit of +100.


Favors can be traded via diplomatic trade or obtained through events and have two purposes. First, an empire can call upon Favors to add another empire's Diplomatic Weight to theirs (+10% per favor) when voting Resolutions in the Galactic Community as long as they don't already vote identically. This does not decrease the other empire's diplomatic weight for the vote. Second, Favors increase the acceptance rate of certain diplomatic agreements or federation laws by +5 for each Favor. An empire can owe another empire up to 10 Favors.

Multiple empires can call upon Favors from the same target empire and one empire can simultaneously call upon Favors from multiple target empires.


Each empire will have a specific attitude towards other empires dictated by their AI personality, diplomatic interactions and the relative power of both empires.

Attitude Trade & Pacts Prefer peace Other Effects Requirements Description
Neutral     none none below This Empire does not consider us relevant to their interests.
Wary     none inferior relative power and shared border This Empire maintains a cautious attitude towards us.
Receptive     more inclined to accept diplomatic pacts diplomatic AI personalities This Empire is interested in closer relations with us.
Cordial     more inclined to accept diplomatic pacts high opinion This Empire is amenable to peaceful coexistence and trading with us.
Friendly     more inclined to accept diplomatic pacts and join a federation high opinion and successful past diplomacy This Empire views us as a friend and may be willing to form an alliance with us.
Protective     more inclined to accept diplomatic pacts and may propose subjugation high opinion and superior relative power This Empire believes that we are weak and need their protection.
Suspicious     none low opinion This Empire views us with suspicion and mistrust.
Rival     none rival with low opinion This Empire views us as their rival.
Hostile     none very low opinion This Empire views us as their enemy. They are likely to attack us if they think they can win.
Domineering     only uses the Subjugation Casus Belli low opinion and Subjugator AI This Empire believes that we would make a fine vassal.
Threatened     none high threat rating This Empire views us as a threatening menace.
Overlord     none overlord This Empire is our overlord.
Loyal     none subject with positive opinion This subject is loyal to us.
Disloyal     considers the relative power of other subjects as well subject with negative opinion This subject resents its subservience to us.
Dismissive     none Fallen Empire This Fallen Empire considers us largely beneath their notice.
Patronizing     may bestow gifts Fallen Empire with high opinion This Fallen Empire views us as errant children in need of their guidance. They may deign to bestow gifts of technology, resources or ships on us.
Angry     will send a demand which will grant them Casus Belli if refused Fallen Empire with low opinion We have angered this Fallen Empire with our actions, and they may declare war to punish us.
Arrogant     no effect distant Awakened Empire This Awakened Empire views us with dismissive arrogance.
Imperious     will propose subjugation neighbor Awakened Empire This Awakened Empire views us as a future subject. They are likely to demand we surrender our independence.
Belligerent     none Awakened Empire with low opinion This Awakened Empire views us as a target of conquest. They are likely to attack us.
Custodial     accepts joining a Federation Guardian Awakened Empires This Awakened Empire believes that it needs to protect us from the crisis currently threatening the galaxy. They are likely to attempt to ally us.
Enigmatic     opinion is hidden and has no impact Ancient Caretakers This Fallen Empire is an ancient artificial intelligence that behaves in a strange and unpredictable manner. We do not know what to expect from it.
Berserk     attacks any empire nearby Malfunctioning Custodians This Awakened Empire is an ancient artificial intelligence that has gone berserk. It is likely to attack anything and anyone around it.

Genocidal DiplomacyEdit

Empires with the   Fanatic Purifiers civic can only engage in diplomacy with empires of the same primary species. Note that this other empire will still have −1000   Opinion towards Fanatic Purifier, unless it is also a Fanatic Purifier (in which case they have +200   Opinion towards each other).

Empires with the   Determined Exterminator civic can only engage in diplomacy with empires with   Machine Intelligence authority or   Mechanical main species.

Empires with the   Devouring Swarm and Terravore civics cannot engage in any diplomacy at all, not even with identical empires. Envoys are thus only useful to them for Espionage and First Contact.


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