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

Annotations already declare this is a non-readonly, non-destructive, non-idempotent, open-world operation. The description adds genuinely useful context the annotations do not carry: the credit cost (10 credits, Tier 1) and the default lead time of 7 days before the event. It does not disclose delivery format, retry/duplicate behavior implied by idempotentHint=false, or any auth/verification requirement.

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?

Two short lines with the action front-loaded and no wasted prose. The bracketed [Group]/[Cost] metadata is terse and informative rather than padding.

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?

An output schema exists, so return values need no explanation. However, for a webhook registration tool the description omits practical essentials: whether the endpoint must be publicly reachable, whether registration can be duplicated, and how it relates to the many sibling webhook and streaming tools.

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%: 'fields' and 'precision' are well documented in the schema, while the required 'url' has no description. The description adds nothing about any parameter, and its '7 days before' default implies a configurable lead time that does not exist as a parameter, which may mildly mislead.

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 states a specific verb and resource: subscribing to eclipse alerts, with a concrete behavioral detail (default 7 days before). It is clear what the tool does, but it does not distinguish itself from the generic astroway_webhooks_subscribe or the streaming eclipse tools (astroway_stream_eclipse_incoming), so an agent cannot route between them from the text alone.

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?

There is no when-to-use guidance, no mention of when to prefer this over astroway_webhooks_subscribe or the stream_* eclipse siblings, and no stated prerequisites (e.g. whether a public URL or account is required). The 'default 7 days before' hint is a behavior detail, not usage guidance.

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