What is the difference between full disclosure for the purposes of pleading and full disclosure at the trial stage?

In Dumont v. Canada, supra, Scott CJM further commented at paragraph 30: 30. During argument it became apparent that substantial disclosure will be made by the plaintiffs of documentary and other evidence intended to be relied upon at the trial stage. This however misses the point. There is a substantial difference between particulars for the purposes of pleading and full disclosure for the purposes of trial. The issues must first be properly defined so that counsel for the defendants can ascertain the case they have to meet and hence the adequacy of the disclosure subsequently offered. 31. For the foregoing reasons, particulars must be ordered, but not to the extent requested by Canada. The demand for particulars was itself too broad and vague. The specificity of this order is intended to narrow the scope of the particulars to be given in a manner which will assist in the definition of the issues.