Incondnosa was a Human world, founded by peaceful secession from the Human Empire. A whole bunch of human artists and scientists thought they knew a better way to live, and eventually they got big enough that the imperial government said “fine, show us” and deeded them a habitable world on the edge of human space. So ten thousand humans, and a hundred million tons of equipment, went out to an empty world, and sought to build their paradise.
They got their infrastructure up and running in record time: water and power, cities and roads, autofarms and autofactories – the works. They set up a weird government based partly on voting and partly on just going out and doing stuff. It seemed to work for them. They had a tiny police force, but they had no poverty and good psychiatric medicine, so they didn't have much crime.
They named one of themselves Supreme Commander of the Armed Forces, but they didn't establish any armed forces for him to command. Fancy titles are nice, but actually being commanded would be contrary to their culture. He spent a lot of time organizing tabletop wargaming sessions, which he tended to win, and tossing around warship design challenges on the relevant engineering puzzle discussion boards.
You might think a world like that would be ripe for invasion. Well, nobody tried. Three reasons. First, no one was entirely certain the Human Empire wouldn't fight to protect them. They weren't part of the empire per se, but there were a lot of friendly relationships. Second, Empire or not they were still humans, and a lot of people remembered how ripe for invasion Earth looked just before the Empire was founded. That hadn't gone well for anyone who'd tried. Finally, there wasn't much worth taking. Just scientists and artists, who were mostly publishing their work to the galaxy anyway.
Once things got settled it was a very nice place to live, so they got a swarm of immigrants from the Empire, and a few more from elsewhere. Everybody was welcome provided they passed acculturation. By twenty years after the founding, Incondnosa had a billion people on it, with cities and infrastructure to match.
At which point the galaxy discovered something funny: mix a scientist with an artist and you get an engineer. The Incondnosans had the best autofactories in the galaxy. Best designs, too. Every detail was the product of an expert's full attention and pride. The designs were published, but in formats that only the Incondnosan autofactories read natively. They had more manufacturing capacity than they actually needed, so they sold the excess stuff to nearby worlds. They didn't use money internally, but Incondnosa as an entity built up some very large bank accounts in foreign worlds.
Which was why a fleet of F'nar raiders decided to attack the place after all.
The fleet jumped straight to the edge of Incondnosa's FTL interdiction, already moving fast and decelerating for contact.
70 milliseconds after jump, space traffic monitoring sent the fleet a form message telling them their approach was dangerous and offering a safe path. The F'nar replied with a generic obscenity. Space traffic monitoring paged police-oncall.
The police officer on duty took a look at the incoming fleet, compared it to historical records, and called the Supreme Commander of the Armed Forces. “I hope you're prepared for this,” he said.
The Supreme Commander paged manufacturing-oncall to request emergency extra quota. He got it.
About 10 minutes after the F'nar jump, autofactories across Incondnosa put aside their normal load to create minimal space ships: less than two meters long, with fast engines, a single energy projector and heavily encrypted comms. There was no room for crew. The ships were powered by small antimatter batteries that could last about three hours of heavy activity. The design was the product of a competition on a mecheng-golf forum that the Supreme Commander had run a few weeks earlier. Best 500 karma he'd ever spent.
Half an hour later, the first of the mini-ships completed quality check and launched. The F'nar were most of the way to Incondnosa.
About an hour after jump, the F'nar arrived at Incondnosa to find it guarded by over a thousand small ships. Even so, they outmassed and outgunned the defenders. They opened fire.
This proved a frustrating experience. Each mini-ship maneuvered quickly and unpredictably. It took several tries to score a direct hit. The mini-ships didn't have much shielding, but they had enough that wide-beam weapons weren't effective. Direct hits were effective, resulting in very satisfying explosions, but the Incondnosans were adding ships to the field faster than the F'nar could destroy them.
The F'nar launched drop-pods of infantry, but regretted it at once. The mini-ships made short work of those.
Briefly the F'nar captain contemplated turning mass-drivers against the Incondnosan cities. But that was madness. He was already betting his life and more that the Human Empire would ignore a war against an independent Human settlement. They wouldn't ignore war crimes.
The Supreme Commander was getting frustrated too. The mini-ships were defending nicely, but they didn't have the raw power to punch through the F'nar shields. He considered creating another class of ships, but the manufacturing latency was too high. He needed a solution now.
He called one of his friends – more a puzzle-gamer than a war-gamer, but still generally fun to hang out with. And an expert on shields.
Most people don't think much about shields. They stop stuff. Sure, if the exact wrong pattern of energy hits them, they suffer resonance and explode, but the odds of that pattern occurring are about a trillion to one. And finding that pattern deliberately is a very obscure art – like picking tumbler locks, only with more differential equations.
The very best shields – that is, the ones designed on Incondnosa – have special dampers to protect against this sort of attack. The F'nar didn't have those. They were a warrior people, who didn't take warnings published in mathematical journals seriously.
The two defenders probed the F'nar flagship's shield generator together for almost twenty minutes before it yielded to a singular matrix decomposition attack. The flagship lost its shielding entirely.
The Supreme Commander offered the opportunity to surrender. The high officers would be put on trial, but the rest of the crews would be spared. The F'nar chose to run, instead. The mini-ships followed, probing for the exact co-efficients to unshield each ship and then destroying them.
By the time the F'nar reached the edge of FTL interdiction, there weren't many left. Those that were, jumped immediately, not waiting for each-other. The mini-ships had no jump engines, so the pursuit ended there.
The Supreme Commander briefly pondered how to best express power at a distance before settling on the obvious. Drawing on the planet's large foreign currency reserves, he put bounties on the officers' heads.
Cleanup took days. The heads were received and paid for. The trash (including thousands of mini-ships with dead batteries) was cleared from near-Incondnosa space and dumped in recyclers. The manufacturing backlog was cleared. Even the parades and festivals eventually quieted down.
The central government met to consider the question of building a real military. Eventually they decided against it. It would run contrary to their culture, after all. And besides: they clearly didn't need one.