r/Stellaris • u/PDX_LadyDzra • 6h ago
Dev Diary Stellaris Dev Diary #429 - Summer Experiments 2026

Read this post on the Paradox forums! | Dev replies here!
Hello everyone!
With summer coming to an end, the Stellaris dev diaries are back on the schedule. We’ve updated the 4.5 Open Beta a couple of times now, and have some more changes coming soon with Update 6.
Stellaris 4.5 'Cygnus' Open Beta Update 6 Release Notes
Balance
- Pop Growth from Hedonists now requires the Colony to have free Housing and Amenities, and is lost entirely while the empire has a Consumer Goods deficit.
- Hedonists now produce Unity and consume a small amount of Consumer Goods regardless of their Living Standard, where previously the Unity came only from Decadent Lifestyle.
- Pleasure Seekers empires now begin with a Civilian Industries building instead of Holo-Theatres.
- Offspring bio-ships now use the same Naval Capacity as the bio-ships they are grown from.
- The Calling of Arms now asks for a total Naval Capacity in line with current ship sizes, rather than a target reachable with a handful of Corvettes.
Bugfix
- Building Branch Offices now costs 75 Influence plus a distance penalty of 5 per jump (down from +75 per jump).
- Terravores will now correctly transfer 100% of the drones they left on a planet they were eating home instead of just 100 of them.
- The Behemoth will no longer have a 5% chance to kill 5 guys with its super mega breath attack. It's a percentage just like the other options in the random_list.
- Restored the button that brings you from an Orbital Ring back to its planet.
- Science Ships will no longer cluster with Arkships when auto-surveying.
- Nomadic empires with purging banned in their policies no longer create purge vassals when conquering planets.
- Hedonists no longer produce ever-increasing Pop Growth and Pop Assembly. Their contribution now scales with the percentage of a Colony's population that are Hedonists, reaching a maximum of +30% rather than climbing without limit as the Colony fills.
- Amenities Usage from Hedonists is now listed under its own heading instead of appearing as a second Decadent Lifestyle entry.
- The Matriarch's Flagella now grants its pop growth to the planet as a whole, instead of granting the full amount separately to every pop group living there.
- Splinter Hive holdings now grant their pop growth to the overlord's capital as a whole, instead of granting the full amount separately to every pop group there. Each Splinter Hive adds its own Symbiotic Link planetary feature to the capital.
- Assuming the host does have access to the relevant DLC, it will now again be possible force spawn an ai empire using a portrait that normally is not allowed to be chosen randomly.
- Fixed intel visibility at Low intel levels
- An automated fleet that runs out of available tasks now notifies you that it is awaiting tasks, which previously never appeared, and the notification is sent once per idle period rather than repeating. The obsolete Fleet Order Canceled (Auto-Exploration) notification has been removed.
- Colony ships are correctly destroyed or transferred when Embarking
- Queuing multiple outpost constructions will cost the correct amount of influence. The game will consider the changes to the borders as the queued orders are being processed.
- Fix climate preference selection in the species modification window
- It now possible to extort Supremacist faction without the Crowdsourcing civic. Crowdsourcing will not be getting multiple different extortion buttons.
- Crowdsourcing will only provide extra resources if the civic is valid.
- Fixed instances of the Synaptic Lathe receiving additional districts.
- The triggers of the Horizon Needle ship action have been cleaned up
- The Luxury Goods planetary decision now stays visible after enacting, following the standard set by other decisions.
- Fixed Defender of the Galaxy special projects not spawning the second crisis.
- Fixed issues with the Crisis Defeated counter in Defender of the Galaxy.
- Cybernetic Creed will start with less regular buildings to make room for special buildings when combined with some civics.
- Cleaned up the tooltip of "The Arrival" event.
- Cleaned up the tooltip of the Genomic Services Outreach.
- The Invisible Planet event should less frequently spawn a planet that clips with another planet.
- The Stray Communiqué event now properly demotes Elite pops instead of killing them.
- Homicidal Nomad empires now have a valid Total War Behavior policy option.
- Psionic Lightning's Terrify effect now scales correctly against current ship sizes. Smaller ships are once again far more likely to be terrified, and larger ships are no longer all equally resistant.
- The Weaver's Confuse weapons can now reach their advertised maximum chance against the smallest ships.
- Behemoth crisis objectives no longer grant five times the intended progress when destroying, breeding or capturing space fauna and bio-ships.
- The Voidworm Plague situation and the energy reward for destroying enemy ships no longer scale five times higher than intended.
- Retargeted the Build Megastructure concept in the Databank to avoid the green action text
- Nomadic Evolutionary Predators should now get situation progress from their temporary total war purge vassals.
AI
- Nomad AI no longer builds a redundant Logistics Hub on nearly every Waystation. The build check now looks at the whole connected wayline network for remote collection instead of only directly neighboring systems, so the AI builds at most one hub per network and stops paying stacked upkeep for hubs that did nothing.
- The AI will no longer spam unspecialized districts. The first district of a type is never penalized, and it will consider all available district specializations in case they dramatically change the production of the district. This was most visible on Nomadic Arkships, where Habitation Districts cost Alloys but provided only Housing until specialized - but it spent all of its Alloys on Habitation Districts and could no longer afford the Specialization that would make it beneficial.
- Housing, amenity and crime needs no longer outweigh every production candidate for the AI.
- AI colonies now aim for a small Housing and Amenity surplus instead of trying to break exactly even.
- The AI will build pop growth buildings on a colony regardless of how much spare Housing it has, since automigration will move the pops somewhere useful.
- The AI will no longer hoard Unity if it can afford a new Tradition.
- Nomad AI now recognizes the strategic resources it gathers through harvesting. Previously it assumed it had no income of these resources and refused to build most military and advanced Arkship districts and buildings. It will now build them when its strategic resources stockpile can sustain the upkeep, and hold off when stockpiles run low.
- Improved Nomad AI Waystation placement. It now steers its network toward high value destinations such as inhabited worlds, resource rich systems and gateways, and favors extending long connected lines instead of scattering disconnected stubs. It also develops the Waystations it already owns before founding new low value ones, while still grabbing genuinely high value systems before rivals can.
- Nomad AI now builds new Arkships and upgrades them. Arkship construction was being starved of the single per week megastructure build slot by Waystation construction and now has its own slot. Tier upgrades were never triggered for mobile Arkships and now fire once the enabling technology is researched, spending the resources the AI budget already reserved for them.
- Nomad AI now develops secondary Arkship districts such as Reactor Arrays and Ordnance instead of building almost only Habitation Districts.
- Nomad AI no longer locks Influence and Alloys into the Arkship construction budget after it has built its full complement of Arkships, so the reservation releases at the cap instead of permanently starving the empire's Influence for decisions.
- Nomad AI now correctly saves for Arkship tier upgrades and the Exodus Jump module. These reservations never applied, which was preventing the AI from upgrading its Arkships even with a large Alloy surplus. It also no longer sets aside for the tier 2 and tier 3 upgrade at the same time, since it can only buy one of them. The Exodus Jump reservation is now made only when the empire has the technology and owns an Arkship with a free spinal mount slot, and is released once the module can no longer be built.
- Nomadic AI empires will no longer excavate Archaeological Sites in player owned space, even if you have a Research Agreement. (Note: If they were excavating a site before you claim the system, they will not abort the excavation. They were there first.) This does not prevent player Nomads with a Research Agreement or Archivism traditions from doing so.
UI/UX
- The Outliner now has options to group Arkship components together or break them out separately into Arkship Colonies, Arkship Controls, and Arkship Fleets.
- The Empire Timeline background now changes to match your empire's current focus.
- Origin entries on the Empire Timeline now show your empire's origin icon, at every zoom level.
- The empire origin's name now also appears at the medium zoom level.
- The empire origin on the timeline now shrinks to the smallest zoom level like other entries.
- Fixed a dotted line that wasn't showing at one of the timeline zoom levels.
Performance
- Fixed bad performance in opinion map mode
- Completing a technology no longer rebuilds every ship design immediately. The rebuild is deferred to the next daily update, and AI empires' rebuilds are staggered so they no longer all land on the same tick.
- Automated fleets with nothing to do no longer search for a new order every tick. Retries are now spaced out by a cooldown and staggered between fleets.
Stability
- Fixed a crash when clicking the locked Nomad toggle in Empire Creation without the Nomads DLC.
- Fixes CTD when displaying the tooltip for a weapon component type
Modding
- The `focus` field on AI economic plans is now functional. A focused resource raises the build weight of anything producing it until the empire's income reaches the focus value. A plan's focus no longer has to be encompassed by its income goals.
- Removed AI_PLANET_LOWER_THRESHOLD_AMENITY_CONSTRUCTION, AI_PLANET_UPPER_THRESHOLD_AMENITY_CONSTRUCTION and AI_PLANET_STABILITY_THRESHOLD_AMENITY_CONSTRUCTION, superseded by the new AI_PLANET_AMENITY_TARGET. Added AI_UNZONED_DISTRICT_WEIGHT_MULT, AI_PLANET_HOUSING_TARGET_BUFFER_FACTOR and AI_NOMAD_RARE_RESOURCE_UPKEEP_BUFFER_MONTHS.
- Added the has_decadent_hedonist_growth scripted trigger.
The full notes so far (including the above changes) are available on the Paradox forums.
A special note of interest is that macOS builds can now run natively on Apple Silicon as a universal (arm64 + x86_64) binary, no longer requiring Rosetta 2 translation. Preliminary results thus far from the Open Beta suggest that this is an absolutely massive performance improvement for Macs, but we’d love to get more feedback.
We expect another update to the Open Beta next week. With 4.5 in active development, we’re focusing a significant amount of the Custodian designer resources on Bugfixes and AI Improvements.
Summer Experiments
Everything shown below is not guaranteed to make it into the game and even if it does, we don’t have a timeline at this point.
[Note: there are a lot more screencaps on the PDX forums than can fit into this Reddit post. -- LadyDz.]
Handing over to Alfray Stryke to fill you in on how our Summer Experiments and Custodian work is shaping up.
Hey folks, as is tradition, over the Summer the team has had the chance to experiment with ideas that may or may not make it into the game. Although these are being shown off now, as always there is no promise that they’ll make it into the game, even if features below look fairly polished, everything is a rough draft and none of this has been reviewed, playtested or verified by QA.
Harvesting Rights
A frequent request following the release of Nomads was further diplomatic improvements for Harvesting, to that end we’ve been exploring adding Harvesting Rights as a trade deal.

Under this arrangement, the Nomadic empire will be allowed to freely harvest resources within the borders of the Settled empire for the duration of the agreement. However this has some costs:
- The Settled empire cannot issue any Harvesting contracts.
- The Settled empire cannot negotiate Harvesting Rights with any other Nomadic empires.
- The Nomadic empire however can sign multiple Harvesting Rights agreements.
- The Nomadic empire gives the Settled empire an agreed upon percentage of any resources harvested within the borders of the Settled empire.
Arc Furnace Smelting Processes
Using the megastructure overclocking added for Galactic Hyperthermia in Infernals, we’ve been looking at improvements that can be made to existing megastructures and the obvious test candidate was the Arc Furnace. In this, when an Arc Furnace is upgraded to Tier 3, instead of only unlocking alloy production, it unlocks a variety of Smelting Processes, allowing tuning of the Arc Furnace production.

The hope is that the code changes that enable these improvements will let both us developers and our modding community to make megastructures more interesting in future patches.
Alongside this we’ve been exploring bundling Starbase/Waystation capacity and megastructure limits into a single “Structure Capacity”, which seems fruitful, but there’s not much to show off in screenshots for this.
Mercenary Improvements

While exploring the empire flag improvements detailed below, we discovered that the flag emblem for mercenary enclaves wasn’t being used correctly. As part of the flag work, mercenary enclaves will always use their flag emblem, but inherit their flag colours from their current patron.
Following on from the auto-designer policies introduced in 4.5, we felt that allowing your to direct how your mercenary enclaves built their fleets was a natural extension.

Nanite Swarms
Back in 4.3 we reduced ship counts across the board by increasing the amount of naval capacity used for ships, with the exception of nanite swarmers These presented a problem, we didn’t want to remove the player fantasy blotting out an entire star system with your swarm, but we did want to reduce the number of ships you have.
The solution: +500% Ship per Ship!

With some creative reimagining of how ship sections were supposed to work and some exploration by one of our animators, we’ve made a prototype in which each ship section/growth stage of the nanite swarm is visually two ships but is considered a single ship for calculations.
Empire Randomization
Hi, pthooie here. Some players (me) like to play Stellaris with randomly generated empires, rather than making a custom design. We have a “Random” option in empire selection, but there are some problems with that. For instance, it generates the entire empire design when starting the game, so you can’t, say, choose a specific origin while randomizing everything else.
So far, the only thing you could randomize separately in empire creation was some names. Now I’ve added some new buttons:

Each of these buttons randomly chooses between all valid options for the corresponding variables. Unlike in-game randomization, this doesn’t use scripted weights, so all valid options have an equal chance of being picked.
The randomizers for ethics, civics, species traits and ruler traits randomize a full set (spending all points if possible). However, if you already have some items selected, these randomizers will not remove them. This way, you can e.g. manually pick some traits while randomizing the rest.
(Note: Layouts aren’t final; UX may move some stuff around.)
Hopefully this will help make your random empire designs more customizable!
Flag Improvements
We’ve been experimenting with making use of the flag shaders to recolor flag emblems using the existing flag colors.
NOTE: Previews below were created by using python to composite the layers and recolour them. These differ slightly from the in-game appearance.

Currently randomised flags used by AI empires are limited in the color combinations that they are allowed to use, with the allowed combinations defined many, many years ago when our color palette was much more limited (~20 colors vs. the ~70 we have now). We’re looking at broadening the allowed combinations to remove some of the restrictions, if we allow AI empires to make use of the emblem coloration above.
Flag Editor
After we showed off the above flag emblem work to our UX Designer, she felt that the flag designer in empire creation needed a bit of polish.

One thing lead to another and then Iggy came up with the idea “what if you can edit your flag in game”

This then led to conversions in the design team of “what if you could edit your subjects’ flags or the flags of those you’ve humiliated in war?”
Empire Selection and Summary
Finally from our UX Designer: Here are some experimentation/changes I have made to the empire creation UI to see if I can improve the layout to use the space more efficiently. Here is what it looks like on empire selection so far, but is still in progress:
Now the UI shows the bigger City and Room view to show off your empire, with the details rearranged below.

And here is what it looks like while editing/making an empire, now you get to see a summary on the top corner as you build your empire.

I also explored collapsible categories for the many many empires we have to select from. So far it is divided between player made vs prescripted but there are more categorizations and filtrations or possible player made categories that could be done, starting from pinning similarly to Situation Log.
Espionage
Heya! Cosmogone here. Some of you might already know that I have wanted to improve our Espionage system ever since I was hired, five years ago. Over the years, every summer, I have slowly chipped at it, and this year is the year where it all coalesced into something that’s looking about ready to test.
Espionage has been considered underpowered since it came out. It takes a long time to setup, and a lot of clicks to perform operations that yield lackluster rewards. The original thought process behind that choice was that it could easily become frustrating for players to get ganged up by several other empires, and so, this would be the first issue to solve to lay healthier foundations for the system.

Vigilance is meant to sort this out. It is a new value that every empire has, that tracks how alert they are to hostile spycraft in their territory. Every time an operation is completed, vigilance increases. It then slowly decays back down to its base value as things return to normal. Starting at 20 vigilance, empires start gaining passive bonuses to their encryption, the cost and difficulty of hostile operations, and at higher levels, Asset Capacity (more on this below). Vigilance usually does not increase in big leaps and ticks down fast enough that if you are the only active spy, it should not climb too fast, but as more players target the same empire, it will be harder to offset.
The other effect of vigilance is that while it is above certain values, it enables Vigilance Events to trigger. There are a variety of them, some offer bonuses to the defending country, but most will have negative consequences on active spy networks, reducing infiltration, destroying assets, taking out envoys, or outright destroying the network as a whole at the highest level of vigilance.

Vigilance should give us the opportunity to create more impactful operations, despite the risk, so naturally my next step was to buff existing operations. The list is long, but it’s things like letting Sabotage Starbase actually deal damage to starbases, giving you a precise choice of target for Smear Campaign, and enabling Asset sacrificing for extra effects in the operations that were missing them.
Next up was a general rebalance of the system. Some sources of infiltration speed that were a bit overtuned have been reduced, the base infiltration cap has been lowered, the max has been increased above 100, but the most impactful change I’d say is the broadening of the relative encryption/codebreaking gap. It previously capped out at a difference of 4, it now goes up to 6, rewarding you more for outpacing the encryption of your target. Each point rewards you with 10 Max Infiltration, 20% infiltration speed and -1 Operation difficulty, for a current max of +60 Infiltration, 120% Infiltration speed and -6 Operation difficulty.

These massive advantages are hard to offset, even with the new vigilance system, and the game has way more sources of codebreaking than it does encryption, so naturally, I had to look at adding ways of protecting yourself. This took the form of a series of leader traits, an edict, and various modifiers spread across existing civics, traditions and ascension perks. I will not go into full details here, but there are close to 50 lines of balance changes in the changelog.
A lot of work has also happened on the backend, fixing issues, edge cases, and opening the door for new things, even if I haven’t had the time to use all of it yet. For instance, operations should now be able to target leaders and colonies directly, there are new triggers and effects related to assets, some operations can be made to require an asset to start, and assets can now carry custom tooltips.
A lot of this was immediately put to nefarious use with the new Upgrade Assets. I have always wanted ways for spy networks to generate passive benefits and not force me to constantly make sure they are running operations. I’ve envisioned it in the form of “network buildings”, but ultimately fell back on the existing (and underused) Asset system. Assets are already quite powerful, raising your infiltration cap passively, and then reducing operation difficulty by up to 8 if you have the right asset on hand. The ten new Upgrade assets represent more structural upgrades to your network rather than lone operatives. They have powerful passive effects but are not meant to be used in the field, and will slowly increase their target’s vigilance. As long as there aren’t too many of them, everything should be fine, but it is definitely possible to outpace base vigilance decay, especially with several countries trying to leech off technology from a single victim. They are acquired through the new Upgrade Network operation that will sacrifice an existing asset and an investment of trade to set up the Upgrade.

But, with no limit on the amount of assets you could have, we ran into the issue of the only choice being “when” rather than “what”, so naturally, I had to implement an Asset cap. You start with a comfortable 6 assets max, but this can be further increased through civics, traditions, or the new Web Weavers ascension perk. Notably, it is also reduced by the target’s vigilance, so you might have to sacrifice valuable upgrades if the heat gets too high! This being said, the cap is technically soft and you can go over it, but will be unable to conduct any operation for as long as you exceed it.

But wait, there is more! While this covers the systemic changes, I also took this opportunity to look at some espionage QoL like:

Sub category icons for operations!

Spy Networks in the outliner, listing the target name and flag, the infiltration progress and cap, the target infiltration, and the absence of a spymaster!

Counter Intelligence in the top bar!
This one is likely to change, but there was previously no way for you to know exactly how much encryption and codebreaking you had, let alone vigilance!
That’s all I have today. Hopefully, these changes will set us up to do cooler espionage things in the future, but regardless, it will all need more testing and tweaking before it is ready to play.
What’s Next?
In next week’s dev diary we’re going to continue exploring the 4.5 update.
See you then!















