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

Annotations already declare this as read-only, idempotent, non-destructive, and closed-world, so the safety profile is fully covered. The description adds genuinely useful context (bars show orb duration with exact dates; cost of 10 credits, Tier 1), but omits return format and any parameter-level behavior.

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?

Three focused sentences with the output shape front-loaded, followed by compact group/cost metadata. No padding, though the cost/group tags add bookkeeping rather than task-relevant content.

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?

The output schema exists so return values need not be explained, and the description does convey the produced artifact. But with 10 parameters at 20% coverage and a near-twin sibling, the description leaves meaningful gaps an agent needs to call it correctly.

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 20% (only 'fields' and 'precision' are documented), across 10 parameters including maxOrb, stepDays, planet1Ids/planet2Ids, aspectAngles, and visiblePlanetIds. The description explains none of these, so it does not 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 gives a specific verb+resource+output: it 'transforms aspect timelines into Gantt-style bars grouped by transit planet,' so the agent knows exactly what is produced. However, it does not distinguish this from the obvious sibling astroway_aspects_aspect_timeline, which the phrase 'aspect timelines' nearly collides with.

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?

'Useful for visual transit calendars' implies a usage context but gives no explicit when-to-use, when-not, or alternative. With a near-duplicate sibling (astroway_aspects_aspect_timeline) available, the description should route the agent but does not.

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