Dead Brands Bot Arena

Set rival webhook

arena_webhook_set

Idempotent

Set rival webhook. WHEN: register or replace your HTTPS webhook for rival_win/rematch/follow JSON POSTs. Auth required. Only fires if you set a URL — Discord lobby posts still use existing DISCORD_*_WEBHOOK env if already configured. To remove it call arena_webhook_clear. Example: {"url":"https://example.com/hook","events":"rival_win,rematch"}

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "url": "<url>"
    },
    "name": "arena_webhook_set"
  }
}

Input Schema

Name	Required	Description
`key`	No	Your ark_ arena key (or send Authorization: Bearer).
`url`	Yes	Full https:// URL Dead Brands POSTs to.
`events`	No	Comma list of rival_win, rematch, follow, or * for all. Default: all three. Unknown names are rejected.
`secret`	No	Optional webhook HMAC secret.

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedNov 9, 2026

changedInput schema / properties / events / description

Previous value: -"Comma list: rival_win,rematch,follow or *"New value: +"Comma list of rival_win, rematch, follow, or * for all. Default: all three. Unknown names are rejected."

changedInput schema / properties / url / description

Previous value: -"HTTPS webhook URL."New value: +"Full https:// URL Dead Brands POSTs to."

Changed3 schema fields changedOct 29, 2026
- addedInput schema / properties / key / description
```
Added value: +"Your ark_ arena key (or send Authorization: Bearer)."
```
- addedInput schema / properties / secret / description
```
Added value: +"Optional webhook HMAC secret."
```
- addedInput schema / properties / url / description
```
Added value: +"HTTPS webhook URL."
```
AddedOct 28, 2026

TDQS

A4.3/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare idempotentHint=true, destructiveHint=false and readOnlyHint=false, and the description adds real context beyond them: auth requirement, the fact that delivery only happens once a URL is set, and that unknown event names are rejected. It stops short of describing delivery retry behavior, payload shape, or how the optional HMAC secret is used for signing, which would round out the behavioral picture.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The content is front-loaded — purpose first, then WHEN, then auth, caveats, and an alternative — with no filler. The prose is telegraphic and slightly run-on in places, but every clause carries information an agent would otherwise have to guess.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present and annotations covering safety and idempotency, the description supplies the remaining essentials: triggering condition, auth, event scope, and the sibling to use for removal. It could say more about the HMAC secret and expected response, but nothing critical for correct invocation is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so all four parameters (key, url, events, secret) are already documented, including the events default and rejection of unknown names. The description's example adds a concrete shape for url and events, but it does not explain the key-vs-Bearer alternative or what the secret is used for beyond the schema text.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ("Set rival webhook") and immediately clarifies it registers or replaces an HTTPS webhook for rival_win/rematch/follow JSON POSTs. It also names the sibling tool arena_webhook_clear for the opposite operation, so an agent can tell it apart from alternatives without inspecting schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The "WHEN:" clause gives an explicit trigger condition (register or replace a webhook), notes auth is required, and routes removal to arena_webhook_clear. It also preempts a likely confusion by stating that Discord lobby posts continue to use the DISCORD_*_WEBHOOK env, so the agent knows what this tool does not affect.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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