Queried by: validatorsdeveloperssubnet owners
The Big Picture
The protocol limits how much children can charge. MaxChildkeyTake prevents children from keeping unreasonably large portions, ensuring parents maintain incentive to delegate.
Why This Matters
Setting child take rate? You can't go above this maximum. It protects the delegation system from breakdown due to excessive child fees.
Example Scenario
Query MaxChildkeyTake() returns 8000 (80%). No child can charge more than 80% take. Attempting to set higher will fail.
Common Questions
- Why is there a maximum?
- Without caps, children could charge 99% making delegation pointless. The cap ensures reasonable economics for both parties.
Use Cases
- Check maximum allowed take when setting child take
- Build UI sliders with correct max bounds
- Verify protocol limits for child economics
- Research child key incentive design
From Chain Metadata
ITEM ( default_childkey_take )
Purpose & Usage
Purpose
Cap on child key commission - protects parents from excessive child fees.
Common Query Patterns
- Single value query
- Verify take rate is within bounds
- Build take rate pickers with correct limits
Stored Value
default_childkey_take (u16)
Relationships
Modified By
Related Events
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);
// Query MaxChildkeyTake storage (no keys - plain value)
const result = await api.query.SubtensorModule.MaxChildkeyTake.getValue();
console.log("MaxChildkeyTake:", result);Version History
v195 block 3,791,350 Added
v220–v232 · runtime versions skipped on chain (never deployed)
v233 block 4,920,350 Internal re-bind
v278–v289 · runtime versions skipped on chain (never deployed)
v290 block 5,947,548 Internal re-bind Current
Runtime Info
View Source- Pallet
- SubtensorModule
- Storage Kind
- Plain
- First Version
- v195
- Current Version
- v411