It doesn’t contain anything I would consider a spoiler.
If you’re extra scrupulous, the closest things are:
A description of a bunch of stuff that happens very early on to set up the plot
One revelation about the character development arc of a non-major character
A high-level overview of technical topics covered, and commentary on the general Yudkowskian position on them (with links to precise Planecrash parts covering them), but not spoiling any puzzles or anything that’s surprising if you’ve read a lot of other Yudkowsky
A bunch of long quotes about dath ilani governance structures (but these are not plot relevant to Planecrash at all)
A few verbatim quotes from characters, which I guess would technically let you infer the characters don’t die until they’ve said those words?
It doesn’t contain anything I would consider a spoiler.
If you’re extra scrupulous, the closest things are:
A description of a bunch of stuff that happens very early on to set up the plot
One revelation about the character development arc of a non-major character
A high-level overview of technical topics covered, and commentary on the general Yudkowskian position on them (with links to precise Planecrash parts covering them), but not spoiling any puzzles or anything that’s surprising if you’ve read a lot of other Yudkowsky
A bunch of long quotes about dath ilani governance structures (but these are not plot relevant to Planecrash at all)
A few verbatim quotes from characters, which I guess would technically let you infer the characters don’t die until they’ve said those words?
As someone who’s only read like 60% of the first book, the only spoiler to me was in the paragraph about Carissa.