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

Annotations already establish openWorldHint, idempotentHint, and non-destructive. The description adds real behavioral context the annotations don't: nudge content (including child routine details) is transmitted to an external endpoint, and the URL must be a public http(s) endpoint rather than localhost/private network. It could go further on auth/permission requirements.

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-loads the core action and keeps the mechanism, constraints, and idempotency note compact across four sentences. Slightly dense but every clause adds information an agent needs.

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 two-parameter, no-output-schema registration tool, the description covers purpose, payload exposure, URL constraints, and idempotent re-registration. Only permission/prerequisite information is absent.

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 0%, so the description carries the burden and largely meets it: it explains that url must be a public http(s) endpoint and that secret is an optional shared secret for HMAC signature verification. Both parameters gain meaning beyond their bare names, though formats (e.g. minimum secret length) are unstated.

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 (Register) and resource (webhook URL to receive nudges) with the exact event set it delivers (nap windows, feeds due, allergen lapses, low stock). It is clearly distinguishable from siblings like get_nudges (pull) and unsubscribe_nudges (teardown).

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 explains what registering accomplishes and that re-registering the same URL refreshes rather than duplicates, which implies the use case. However, it never states when to prefer this over get_nudges polling or how it relates to unsubscribe_nudges, leaving the routing to inference.

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