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

The description goes beyond the annotations by disclosing that the signing secret is returned only once and should be stored, and it names specific error conditions (webhook_limit_reached, webhook_url_taken). This is meaningful behavioral context for a create operation, though it does not fully describe response shape or all side effects.

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?

Three sentences convey purpose, a security-critical warning, limits, error codes, and a prerequisite with no filler. The structure front-loads the main purpose and then covers constraints, 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 create operation with no output schema, the description covers the most important response aspect (one-time signing secret) and key constraints/errors. It does not describe the full returned webhook object, but the schema plus these details are sufficient for a competent agent to call it correctly.

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 description coverage is 100%, so the schema already documents all parameters. The description adds context about the webhook's behavior and limits but does not explain individual parameters, which is acceptable given the schema's completeness.

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 clearly identifies the verb ('Adds') and resource ('a webhook'), and adds the behavioral detail that it receives every submission as a JSON POST. It does not explicitly differentiate from sibling update_webhook/delete_webhook, but the action is unambiguous enough to recognize.

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 description gives useful context for when the tool can be used: a form supports up to 10 webhooks, one per URL, and the plan must include webhooks. It does not state when to prefer an alternative such as update_webhook, so exclusion guidance is missing.

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