Too Many Children
TooManyChildren is a documented Subtensor standard error raised when a parent hotkey’s child list
for a subnet would exceed the allowed limit. The standard-errors reference describes it as “Too many
children”
(Subtensor Standard Errors).
What It Means
A child hotkey lets a parent delegate
re-route a share of its stake to a separate validating key on a given subnet, and a parent may have
at most five children on any one netuid. TooManyChildren is the rejection when a requested child
list for a parent on a subnet would push that count past five
(Child Hotkeys,
Subtensor source: set_children.rs).
The check counts the full requested child list as a whole rather than counting one addition at a time, so a single call that names six or more children at once fails the same way a call that pushes an existing five-child list over the limit would (Subtensor source: set_children.rs).
Why It Appears
Scheduling new child relations for a parent hotkey on a subnet is the main place this limit applies. The same consistency check also runs when a hotkey swap re-validates a parent’s existing child relations under its new identity, so the five-child cap is enforced consistently rather than only at the moment children are first scheduled (Subtensor source: set_children.rs).
Distinction from Proportion Overflow
TooManyChildren and ProportionOverflow are both raised from the same child-relation consistency
check, but they guard different properties of the requested child list. TooManyChildren counts how
many children are listed. ProportionOverflow instead sums the stake proportions assigned across
those children and fails if that sum cannot fit in the chain’s proportion accounting, independent of
how many children were listed
(Subtensor Standard Errors: ProportionOverflow,
Subtensor source: set_children.rs).
- TooManyChildren — the child list has more than five entries.
- ProportionOverflow — the listed children’s combined stake proportion doesn’t fit.
Reader Boundary
This page defines the meaning of the error label and the count limit that raises it. It does not describe how child hotkeys are scheduled, how child take is calculated, or the other checks in the same consistency step; those are documented separately (Child Hotkeys, Subtensor source: set_children.rs).