'Agricultural' is a trade classification, but it just tells us what sort of products the world would generate IF it did export anything. It doesn't mean it necessarily does export; certainly not necessarily on any grand scale.
Hans
fwiw I've generally taken the Trade Classification as an indicator of the type of trade the world engages in, with the volumes coming from (taking cue from at least) the trade tables on pg. 11 of LBB 2.
So a world with no trade classifications at all is not interested in trade, though there will generally be a random assortment of goods to ship or items to speculate on. While worlds with actual trade classifications point to the types of goods likely to make up said goods. Taking cues from the Speculative Trade table (pg 47 LBB 2) modifiers for the freight.
As an example the Ag Ni world you rolled with Pop 6 will have a fair bit of trade available for any Free Traders who come through (unlikely to have a subsidized service given the rest) and the bulk of it will be:
Exports (neg purchase DMs): Textiles, Liquor, Wood, Radioactives, Petrochemicals, Grain, Meat, Spice, Fruit, and Gems.
Imports (pos resale DMs): Aluminum, Special Alloys, Aircraft, Air/rafts, Computers, ATVs, AFVs*, Farm Machinery, Electronic Parts, Mechanical Parts, Cybernetic Parts, Computer Parts, Machine Tools, and Vacc Suits.
* I've never really gotten the pos DM Ag for AFVs
So there's a lot of mining and farming going on and exports of raw materials and food and some finished crafts.
In return they aren't luddites and while they don't produce much or any high tech stuff locally they do use it extensively and make their own repairs.
Something like that.
P.S. And fwiw E isn't really a Starport
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and TL6 isn't really that low
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(they could even have a "primitive" orbital presence, sputnik or better)