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

Annotations declare the write/idempotency/openWorld profile, so the bar is lower, and the description still adds real value: it names the signing_secret return and the X-AstroWay-Signature HMAC-SHA256 verification mechanism, plus the 10-credit cost. It does not cover delivery retry behavior or what happens on a duplicate subscription (relevant given idempotentHint=false).

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-loaded and tight: the core action, the security detail, and the metadata block all earn their place. The only weak point is the truncated event list, which spends a sentence on information that is both incomplete and inconsistent with the schema.

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, yet the description helpfully notes the signing_secret, so return values are adequately covered. The gap is the event enumeration mismatch (3 listed vs 12 in the enum) and the absence of any subscription-management context (e.g., how this relates to astroway_webhooks_id or the per-event siblings) for a tool with 43 siblings.

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 50% and the schema already documents `fields` and `precision` in detail, so the description contributes little beyond the required-parameter line. The event list it does provide ('report-ready, transit-alert, eclipse-alert') is a partial and potentially misleading subset of the 12-value enum in 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 ('Subscribe to outbound webhook deliveries') with the effect (returns a signing_secret) clearly named. However, it does not distinguish itself from the many sibling per-event webhook tools (astroway_webhooks_dasha_change, astroway_webhooks_eclipse_alert, etc.), leaving the agent to infer whether this is the generic subscription entry point or a duplicate.

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?

No guidance on when to use this versus the sibling per-event webhook tools or the stream_* alternatives. The only contextual cue is '[Required: event, url]', which restates the schema rather than advising usage. An agent gets no when/when-not framing.

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