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According to https://clojure.github.io/tools.tools/clojure.tools.tools.api.html#var-show you can invoke the tools show command like,
Example: clj -Ttools show deps-graph
I might be missing something but it seems you need a key, like
lucretius:~/work/living_clojure$ clj -Ttools show new Key is missing value: new lucretius:~/work/living_clojure$ clj -Ttools show :tool new {:lib io.github.seancorfield/deps-new, :coord {:git/tag "v0.4.13", :git/sha "879c4eb50df92fcd8c11423c2081e00998d7b613", :git/url "https://github.com/seancorfield/deps-new.git"}} Default namespace: org.corfield.new
Where do you see Example: clj -Ttools show deps-graph ?
I don't see that at the link to the doc.