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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds the credit cost ('10 credits, Tier 1') and the endpoint, which is genuinely useful context the annotations do not carry. It does not mention the cheaper chart-passthrough path (1 credit) or any rendering behavior, leaving some value on the table.

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 short lines, with the substantive description of the output front-loaded ahead of the bracketed metadata. No wasted words, though the metadata lines could have been spent on usage guidance instead.

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 explanation, and the annotations cover the safety profile. However, for a render tool sitting among a dozen render_* siblings, the absence of any indication of when this grid is preferable to a wheel or aspect bar leaves an agent guessing.

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 a middling 67% and the description adds nothing about the three parameters — body, fields or precision — nor about options like format, theme, size or bodies. Baseline 3 is appropriate given the schema itself carries detailed nested descriptions ('A chart you already hold, drawn as is: no birth data, 1 credit').

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 states a concrete verb+resource: it renders a triangular aspect matrix where rows/columns are planets and each cell carries an aspect glyph and orb, and it names the layout style ('standard textbook layout'). This clearly separates it from data-oriented siblings like astroway_aspects_aspect_bar or astroway_calendar_aspects, but it never explicitly contrasts itself with the other render_* visualization tools (e.g. render_wheel_western), so no positive sibling differentiation.

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 and no alternatives are named. An agent must infer from the name alone that this is the grid-format visualization of aspects rather than the wheel or timeline. The only supplied context is metadata (group, endpoint, cost), not usage direction.

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