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

Annotations already supply the safety profile (openWorldHint=true, destructiveHint=false, idempotentHint=false), so the bar is lower. The description adds genuinely useful context in the cost tag (10 credits, Tier 1), but says nothing about the forecast window's default, pagination, or why readOnlyHint is false for what reads like a query.

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?

Very compact and front-loaded: purpose first, then the group and cost metadata. Nothing is wasted, though the terse phrasing leaves real gaps rather than being optimally economical.

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 not be explained. However, for a 3-parameter tool with an undocumented `days` parameter and no usage or window-default guidance, the definition is only minimally sufficient for correct invocation.

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 undocumented parameter is `days`, which the description only restates as 'N days' without units, default, or maximum. The compact-mode params (fields, precision) are documented in the schema but receive no mention here, so the description adds little beyond structured data.

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 resource (planet sign-ingresses) and a temporal scope (next N days), which lets an agent distinguish it from siblings like astroway_stream_positions or astroway_stream_retrograde_alerts. It is clear but offers no explicit contrast with those siblings.

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 prerequisites, and no named alternatives among the many astroway_stream_* siblings. The group/cost tags describe billing, not invocation conditions.

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