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

Adds substantial behavior beyond annotations (readOnly=false, openWorld=true, idempotent=false, destructive=false): the endpoint starts pending and only receives test events until the owner confirms on the website, the owner is emailed, the signing secret is returned only once, deliveries use Standard Webhooks signed headers, and only account-owner API keys or connected apps can create endpoints. This covers lifecycle, auth, and irreversibility that annotations alone do not.

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

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

Front-loaded with purpose, then lifecycle, secret handling, and permissions in four tight sentences with no filler. Some sentences are dense (parenthetical Slack/Teams clause, combined pending/confirmation clause), but nothing is redundant.

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

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

Covers everything an agent needs for a non-idempotent, open-world create call with a one-time secret and a pending-verification lifecycle: who can call it, what state the endpoint starts in, what deliveries carry, and when the secret is available. An output schema already exists, so return values need no explanation here.

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

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

Schema coverage is 100%, so the baseline is 3; the description adds real value by clarifying that the url parameter may be a Slack or Microsoft Teams incoming webhook, not just a custom receiver, which the schema text does not say. It says nothing extra about the events parameter, so it is not a 5.

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

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

States a specific verb and resource ('send the account's transfer events to an HTTPS address') and names the two receiver types (own receiver, Slack/Teams incoming webhook). An agent can distinguish it from siblings like change_webhook_endpoint_url, update_webhook_endpoint, or rotate_webhook_secret without opening schemas.

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

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

Clear context for use: to send transfer events to an HTTPS address, with the accepted receiver types spelled out. It does not explicitly name alternatives such as update_webhook_endpoint or change_webhook_endpoint_url, so an agent still has to infer that this is create-only, not edit.

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