SlingHook

Create endpoint

create_endpoint

Creates a catch URL for a webhook provider and returns it to paste into webhook settings. Reuses an existing endpoint with the same name instead of duplicating it.

Instructions

Creates a new catch URL (endpoint) in the current workspace and returns the URL to paste into the provider's webhook settings. If an endpoint with the same name already exists, returns that one instead of making a copy. Plan limits apply (Free has 3 endpoints). It does not take a signing secret: secrets are added in the dashboard so they never pass through the conversation.

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": {
      "name": "<name>"
    },
    "name": "create_endpoint"
  }
}

Input Schema

Name	Required	Description	Default
`name`	Yes	What it is for, e.g. "Shopify orders (local)"
`relay_to`	No	Optional URL to relay each event to, e.g. http://localhost:3000/webhooks
`signature_scheme`	No	Provider signature to check once a secret is added; auto detects it from headers. Standard covers Standard Webhooks / Svix	auto

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 9, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Adds real behavior beyond the annotations: same-name calls return the existing endpoint rather than duplicating, plan caps apply, and secrets are deliberately kept out of the conversation. The name-based dedupe sits in mild tension with idempotentHint=false, but it describes a distinct dedupe rule rather than contradicting the hint, so no contradiction is flagged.

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?

Four short sentences, front-loaded with the action and return value, then dedupe behavior, limits, and the secret exclusion. Every sentence 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.

Completeness5/5

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

For a three-parameter creation tool with no output schema, the description covers the return value, duplicate handling, quota constraints, and the deliberate omission of secrets. Nothing an agent needs to call it correctly 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 description coverage is 100%, so the schema already documents name, relay_to, and signature_scheme. The description adds only the negative fact that no signing-secret parameter exists, which is useful but does not deepen per-parameter meaning beyond the schema.

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 ("Creates a new catch URL (endpoint) in the current workspace") and even names the return value (the URL to paste into the provider's webhook settings). No sibling tool creates endpoints, so the definition is unambiguous against list_endpoints, run_scenario, and the rest.

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

Usage Guidelines4/5

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

Gives clear context for when to call it (setting up a provider webhook) and an explicit exclusion: it does not take a signing secret, which is added in the dashboard instead. It also warns about plan limits (Free has 3 endpoints). It stops short of naming an alternative tool, but no sibling performs this action.

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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