NameWhisper MCP Server

cancel_listing

Cancel an active ENS name listing by generating Seaport cancel() calldata. Pass order hash and seller wallet; optionally include sibling hashes to cancel multiple orders atomically.

Instructions

Cancel an active ENS name listing by submitting Seaport's cancel() on-chain.

Returns the unsigned Seaport cancel() transaction calldata. Your wallet signs and submits; once mined, Seaport marks the order invalid and no marketplace (NW, Grails, OpenSea) can fulfill it anymore.

Only the original seller (the order's offerer) can cancel. If you cross-posted to OpenSea, you signed a second 'opensea' variant of the listing — pass BOTH order hashes as alsoCancel so a single tx kills both variants atomically.

For cancelling offers you've made as a buyer, use cancel_offer instead.

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": {
      "orderHash": "<orderHash>",
      "walletAddress": "<walletAddress>"
    },
    "name": "cancel_listing"
  }
}

Input Schema

Name	Required	Description
`orderHash`	Yes	Seaport order hash of the listing to cancel (from get_name_details or the orderbook)
`alsoCancel`	No	Sibling order hashes to cancel atomically in the same tx (e.g. the OpenSea-variant counterpart of an NW listing). Seaport.cancel() accepts an array — cancelling N orders costs barely more than cancelling one.
`walletAddress`	Yes	Wallet address of the seller. Must match the original offerer on the order.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.2.0Jul 31, 2026

TDQS

A4.7/5.0

Behavior5/5

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

With no annotations, the description carries the full burden and does so thoroughly. It discloses that the tool returns unsigned calldata, requires the wallet to sign and submit, marks the order invalid only after mining, and blocks all marketplaces. It also reveals the atomic cancellation behavior and permission constraint.

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

Conciseness5/5

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

The description is front-loaded with a clear purpose sentence, and every subsequent sentence adds critical information: return value, signing process, effect, permission, cross-posting, and alternative. No waste; length is justified by complexity.

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

Completeness5/5

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

Despite having no output schema and no annotations, the description fully covers what the tool returns, how it works, security/permission constraints, marketplace impact, and the alternative tool. It is complete for an agent to correctly select and invoke the tool.

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 baseline is 3. The description reinforces param meaning but does not add substantial new semantics beyond the schema's own detailed descriptions. The alsoCancel and walletAddress nuances are already present in the schema, and the description primarily restates them in narrative form.

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?

The description opens with a specific verb and resource: 'Cancel an active ENS name listing by submitting Seaport's cancel() on-chain.' It clearly distinguishes from sibling tools by explicitly pointing to cancel_offer for buyer offers, and the cross-posting nuance further differentiates it from other listing operations.

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?

Explicit guidance is provided: 'For cancelling offers you've made as a buyer, use cancel_offer instead.' It also states the precondition that only the original seller can cancel and explains the alsoCancel use case for cross-posted listings, giving clear when-to-use and when-not-to-use context.

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