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

No annotations exist, so the description carries full burden. It describes a safe read operation ('List') and explains the purpose of webhooks. While it doesn't detail return behavior or plan-dependent errors, the tool is simple and side-effect-free, so transparency is adequate.

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?

The description consists of two concise sentences with no fluff. It immediately states the action, followed by a clarifying definition, making it efficient and easy to scan.

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?

For a simple listing tool with one optional parameter and no output schema, the description covers the core functionality and plan restriction. However, it doesn't mention the return format (e.g., list of webhook objects) or any pagination, leaving some ambiguity about the response.

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% and the parameter is well-described in the schema itself ('Send16 API key (overrides SEND16_API_KEY env var)'). The description adds no further parameter detail, so the baseline score of 3 is appropriate.

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?

The description explicitly states 'List configured outgoing webhooks' with a precise verb and noun, and clarifies what outgoing webhooks are—'your endpoints that Send16 POSTs delivery events to'. This clearly distinguishes the tool from siblings like create_webhook or delete_webhook.

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?

The context is clear: use this to view existing webhooks. However, no explicit when-to-use or when-not-to-use guidance is provided. The mention 'Outgoing webhooks are a plan feature' implies a usage precondition but doesn't fully exclude alternatives.

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