TooManyChildren

Error Re-added v195 → v202, v205 → v212, v216 → v216, v217 → v219, v233 → v315, v320 → v326, v334 → v377, v385 → current 7.62

You've exceeded the maximum number of child hotkeys (5).

Encountered by: validatorsdevelopers

Why This Error Exists

The child key limit (currently 5) prevents overly complex authority hierarchies that would be expensive to compute and validate. Five children is sufficient for most multi-validator setups while keeping the consensus weight calculations manageable. This limit may change via governance.

Deep Dive

The maximum of 5 children applies per (parent_hotkey, netuid) combination. You can have 5 children on subnet 1 and 5 different children on subnet 2. The limit is enforced at the set_children call - if your array exceeds 5 entries, the transaction fails entirely (no partial success).

Debugging Example

You call set_children(netuid=1, hotkey=5Parent..., children=[C1, C2, C3, C4, C5, C6]). Error: TooManyChildren. You have 6 children but max is 5. Solution: Remove one child from the array. Consider which child provides least value and exclude it.

Prevention Tips

  • Validate children.length <= 5 before calling set_children
  • If you need more children, consider a tree structure: parent -> 5 children, each child -> 5 grandchildren
  • Use clear naming/documentation to track which children are active

From Chain Metadata

Too many children MAX 5.

What This Means

You've exceeded the maximum number of child hotkeys (5).

Common Causes

  • Trying to add more than 5 children
  • Maximum is a network-wide limit

How to Fix

  • Reduce the number of children to 5 or fewer
  • Remove some existing children before adding new ones

Storage to Check

Thrown By

Version History

v195 block 3,791,350 Added
v205 block 4,209,446 Re-added
v216 block 4,510,996 Re-added
v217 block 4,590,522 Re-added
v233 block 4,920,350 Re-added
v320 block 6,523,566 Re-added
v334 block 6,811,690 Re-added
v385 block 7,782,670 Re-added Current

Runtime Info

Pallet Index
7
Error Index
62
Error Code
7.62
Runtime Version
v393