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

Goes well beyond the annotations: discloses the signing secret is returned only once, the exact HMAC-SHA256 signature header and format, that private/internal addresses are refused, the 10-per-account cap, free pricing, and ~1 minute delivery latency. These are non-obvious operational facts an agent cannot infer from readOnly/openWorld/idempotent hints.

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 dense sentences with zero filler; the primary action and trigger come first, followed by return/verification semantics, then constraints. Every clause carries actionable information.

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?

With no output schema, the description fully covers the return value (secret once) and verification procedure, plus constraints and latency. An agent has everything needed to call and handle the result 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 coverage is 67%, and the description compensates by explaining that the url must be public with private/internal addresses refused, plus the account cap constraint. It also names the two event values, though the events parameter's default and wildcard are already covered by the schema.

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+resource (register a webhook URL) and the exact triggers (video.completed / video.failed) with delivery mechanism. An agent can distinguish it from autoshort_list_webhooks and autoshort_delete_webhook without opening a schema.

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?

Explicitly frames the use case as an alternative to polling ('instead of polling'), which tells the agent when this is the right call. It does not explicitly route away from siblings (e.g., use delete_webhook to remove), so it falls short of a 5.

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