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

Annotations already declare the full safety profile (readOnly, idempotent, non-destructive, closed-world), and the output schema covers return values. The description adds useful operational context by disclosing the group and the 10-credit Tier 1 cost, but says nothing about auth, rate limits, or what 'nearby' means operationally.

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?

The description is one compact sentence with the core purpose front-loaded, followed by scoped metadata lines for group and cost. Every element earns its place, though the parenthetical examples slightly lengthen the opener without changing agent behavior.

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 read-only, output-schema-backed tool, the description adequately conveys purpose and output scope. However, it leaves usage routing and the roles of birthDate/targetDate unstated, which are the remaining gaps an agent needs to call this correctly versus 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 description coverage is only 50%: birthDate and targetDate have no descriptions, only patterns. The description's 'age-based' and 'nearby' wording hints that birthDate drives the computation and targetDate anchors 'nearby', but it never explains these two undocumented parameters or their format, so it fails to compensate for the coverage 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?

The description names a specific resource ('age-based wellness milestones') and gives concrete examples (Saturn return, Uranus opposition, hormonal shifts), plus the output scope ('nearby + full list'). It is clear what the tool returns, but it does not explicitly differentiate itself from overlapping siblings like astroway_family_saturn_return_cycles or astroway_wellness_sleep_cycles.

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 statement of when to use this tool, when not to, or which sibling to prefer for overlapping age-cycle content. The 'nearby + full list' clause describes output scope but gives no selection guidance, leaving usage to inference.

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