diff --git a/man/frama-c.1 b/man/frama-c.1
index 27e9941f2597e2be1899c63954d2307bf2e10d68..5fe5295b91b14ef7d0e96ae47b15b006f2980c62 100644
--- a/man/frama-c.1
+++ b/man/frama-c.1
@@ -160,6 +160,18 @@ lvalue it is assigned to.
 Otherwise, a temporary variable is used and the cast is made explicit.
 Defaults to yes.
 .TP
+\-generated\-spec\-mode \f[I]mode\f[R]
+selects which \f[I]mode\f[R] will be used to generate missing
+specifications.
+Can be one of: \f[I]frama\-c\f[R], \f[I]acsl\f[R], \f[I]safe\f[R], or
+the name of a custom registered in plug\-in.
+.TP
+\-generated\-spec\-custom \f[I]c_1:m_1,\&...,c_n:m_n\f[R]
+fine\-tunes missing specification generation by manually selecting modes
+for each clause.
+Can be one of: \f[I]frama\-c\f[R], \f[I]acsl\f[R], \f[I]safe\f[R],
+\f[I]skip\f[R], or the name of a custom registered mode.
+.TP
 \-config \f[I]dir\f[R]
 overrides default Frama\-C configuration directory
 .TP
diff --git a/man/frama-c.1.md b/man/frama-c.1.md
index dfcc64130a0a5f126644e5818c73a4dc67551348..0715eff62118a7e6ef21cb4dfc67bb741aaeff44 100644
--- a/man/frama-c.1.md
+++ b/man/frama-c.1.md
@@ -149,6 +149,16 @@ syntax. Defaults to yes.
 it is assigned to. Otherwise, a temporary variable is used and the cast is made
 explicit. Defaults to yes.
 
+-generated-spec-mode *mode*
+: selects which *mode* will be used to generate missing specifications.
+Can be one of: *frama-c*, *acsl*, *safe*, or the name of a custom
+registered in plug-in.
+
+-generated-spec-custom *c_1:m_1,...,c_n:m_n*
+: fine-tunes missing specification generation by manually selecting
+modes for each clause. Can be one of: *frama-c*, *acsl*, *safe*, *skip*, or
+the name of a custom registered mode.
+
 -config *dir*
 : overrides default Frama-C configuration directory