MaxDelegateTakeSet

Event Re-added v149 → v165, v195 → v219, v233 → v247, v252 → v265, v273 → v277, v290 → v315, v320 → v326, v334 → v367, v372 → current #65

Emitted when the maximum allowed delegate take is changed.

View events on chain

Useful for: validatorsdelegatorsanalyticsdevelopers

The Big Picture

The max delegate take caps how much commission validators can extract. It's a delegator protection mechanism - validators can't set predatory rates above this ceiling. Lowering the max protects delegators; raising it gives validators more pricing freedom. Existing delegates above a new lower max get grandfathered but can't increase further.

Why This Matters

As a delegator, this is your protection ceiling - no validator can take more than this. As a validator, this caps your earning potential from commission. Changes to this affect the entire delegation marketplace's economics.

Example Scenario

To protect delegators from excessive commissions, governance lowers max take from 50% to 25%. MaxDelegateTakeSet fires. Validators currently at 40% take can stay there (grandfathered) but can't increase. New delegates start at default and can only raise up to 25%. Market gravitates toward fairer rates.

Common Questions

What happens to validators above the new max?: They keep their current take but can't increase it. If they ever decrease, they can't go back above the new max. Over time, this naturally pushes the market below the ceiling.
Why not just set max take to 100%?: A 100% take would let validators keep all emissions, defeating the purpose of delegation. The cap ensures delegators always receive meaningful returns.
How is max take different from default take?: Default is the starting point for new delegates. Max is the absolute ceiling. Default <= Max. Delegates can raise take from default up to max (within rate limits).

Use Cases

Track maximum commission validators can charge
Monitor network-wide delegator protection policies
Build validator compliance checking tools
Understand the validator commission ceiling

How to Use This Event

→ Monitor max take to understand worst-case delegation terms
→ Track governance changes affecting delegation economics
→ Build compliance tools for validator monitoring

From Chain Metadata

maximum delegate take is set by sudo/admin transaction

Triggers

Preconditions

Caller has admin/sudo privileges
New max is valid percentage

Effects

Postconditions

MaxDelegateTake storage updated

Side Effects

Existing delegates above new max cannot increase take

Event Data

#	Name	Type	Description
0	arg0	u16	Event field #0 (u16)

Code Examples

import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";

const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });

// Subscribe to MaxDelegateTakeSet events
api.query.system.events((events) => {
  events
    .filter(({ event }) =>
      event.section === stringCamelCase("SubtensorModule") &&
      event.method === "MaxDelegateTakeSet"
    )
    .forEach(({ event }) => {
      console.log("MaxDelegateTakeSet:", event.data.toHuman());
    });
});

Version History

Version:

v149 block 3,014,339 1 args

v195 block 3,791,350 1 args

v233 block 4,920,350 1 args

v252 block 5,163,656 1 args

v273 block 5,659,032 1 args

v290 block 5,947,548 1 args

v320 block 6,523,566 1 args

v334 block 6,811,690 1 args

v372 block 7,430,358 1 args Current

Runtime Info

View Source

Pallet Index: 7
Event Index: 65
First Version: v149
Current Version: v393

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