A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
A player, 10 November 2007
According to ruling A and this one taking into consideration the wording of the stronghold I presume this is legal:
Player A attacks and assigns Naval Samurai XX. Player B defends with random Personality ZZ.
Player A declares Naval Invasion and proceeds to take first battle action. Player A plays The Mantis's Strength to shoot the opponents personality ZZ. Player A reacts and attaches Pincers and Tail. Then Player A gains the extra action off the box.
Take note that the trait on Eastern Hub Port requires only that a battle action resolves so that a card is attached.
[Mod edit: Slang removed. -ZF]
Zen Faulkes (rules official), 10 November 2007
Player A attacks and assigns Naval Samurai XX. Player B defends with random Personality ZZ. Player A declares Naval Invasion...
There is no such thing in Samurai Edition rules.
and proceeds to take first battle action. Player A plays The Mantis's Strength to shoot the opponents personality ZZ. Player A reacts and attaches Pincers and Tail. Then Player A gains the extra action off the box.
No. The action that attached Pincers and Tail was not a Battle action; it was a Reaction.
When something says, "After an action does this effect," you look only at the printed effect of that action for that effect. You don't get to trawl through all the secondary and tertiary and quaternary effects made possible by Reactions and triggered traits.