MaxChildKeyTakeSet
Event v195 → v219, v233 → v247, v252 → v265, v273 → v277, v290 → v315, v320 → v402, v411 → v422, v423 → v424, v432 → v440, v441 → current #48Emitted when maximum child key take rate is changed.
View events on chainThe Big Picture
When parent hotkeys share rewards with child keys, the child can set their own take (commission) on their allocated portion. MaxChildKeyTake caps this, preventing child keys from taking excessive commissions. This protects the economic structure of validator organizations and ensures allocated rewards flow through reasonably to stakers.
Why This Matters
If you're delegating to a parent hotkey with children, you need to understand the full take structure. The parent takes their cut, then allocated funds go to children, who take their cut. MaxChildKeyTake limits how much children can extract, protecting your effective return.
Example Scenario
Governance sets MaxChildKeyTake to 20%. MaxChildKeyTakeSet fires. Child keys trying to set 30% take will fail - they're capped at 20%. This ensures that even in complex validator hierarchies, rewards flow through to end stakers reasonably.
Common Questions
- How does this interact with delegate take?
- They're separate. Delegate take is what the main validator charges. Child key take is what children charge on their allocation. Both have their own min/max limits.
- Why cap child key take separately from delegate take?
- Parent-child relationships have different economics. Children are often partners or referrers, not independent validators. Different caps allow different incentive structures.
- What if a child key is currently above the new max?
- Similar to delegates: they're grandfathered but can't increase. If they ever lower their take, they can't raise it back above the new max.
Use Cases
- Track maximum commission child keys can charge
- Understand validator organization commission limits
- Monitor network policies for parent-child relationships
- Build validator structure analysis tools
How to Use This Event
- → Monitor for changes affecting validator organizations
- → Track governance policies for complex validator structures
- → Build tools analyzing child key economics
From Chain Metadata
maximum childkey take set
Migration Notes
arg0 changed from u16 to PerU16
Update decoders: SCALE encoding is positional, so any signature change (added, removed, or type-changed fields, or storage shape changes) shifts byte offsets and existing decoders will misparse this item. Re-derive types from the new metadata.
Triggers
Emitted by
Preconditions
- Caller has admin/sudo privileges
Effects
Storage Modified
Postconditions
- MaxChildKeyTake updated
Side Effects
- Child keys cannot set take above this value
Event Data
| # | Name | Type | Description |
|---|---|---|---|
| 0 | arg0 | PerU16 | Event field #0 (PerU16) |
Code Examples
import { createClient, Binary } from "polkadot-api";
import { getWsProvider } from "polkadot-api/ws";
import { sub } from "@polkadot-api/descriptors"; // generated by: npx papi add sub -w wss://entrypoint-finney.opentensor.ai:443
const client = createClient(getWsProvider("wss://entrypoint-finney.opentensor.ai:443"));
const api = client.getTypedApi(sub);
// Subscribe to MaxChildKeyTakeSet events
client.finalizedBlock$.subscribe(async (block) => {
const events = await api.event.SubtensorModule.MaxChildKeyTakeSet.get(block.hash);
for (const evt of events) {
console.log("MaxChildKeyTakeSet:", evt.payload);
}
});Version History
Runtime Info
View Source- Pallet Index
- 7
- Event Index
- 48
- First Version
- v195
- Current Version
- v472