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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description's only added behavioral fact is the cost (100 credits, Tier 4), which is genuinely useful for an agent budgeting calls, but nothing is said about latency, auth, or output shape.

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?

It is short and front-loaded, but the terseness here reflects under-specification rather than efficient communication. The metadata lines consume half the length without adding invocation help.

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 prose, but the description leaves key input questions open: how planets must be named, which chart object is required for a natal calculation, and what the aspectType enum means in context. For a 7-parameter tool with a nested birth-data object, this is thin.

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 only 43%, and the undescribed parameters include the three required ones (planet1, planet2, aspectType). The phrase 'between two planets' loosely implies planet1/planet2 but gives no naming convention or accepted values, and aspectType, language, fields and precision get nothing despite the gap.

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 and resource: an explanation of an aspect between two planets. An agent can tell what it does, though it never contrasts itself with the sibling astroway_mcp_ai_explain_transit, which is the nearest alternative.

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 mention of alternatives such as explain_transit or the report tools. The agent must infer usage entirely from the name.

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