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

Annotations already declare this a safe, idempotent, non-destructive read, so the safety profile is covered. The description adds the endpoint and the 10-credit cost, which is useful operational context, but it omits the 1-credit pre-computed-chart path and the svg-vs-json default that materially affect how the call behaves.

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?

Two tight sentences with the layout described first, followed by structured metadata tags for group, endpoint, and cost. No filler; the only slight redundancy is repeating the wheel metaphor in the title and body.

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 annotations cover the safety profile. However, for a tool with a dual-mode input (natal birth data vs. two pre-computed charts) and a rich options object, the description leaves the agent to discover the calling modes entirely from the schema.

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 nested object descriptions are exhaustive, so the schema carries the parameter burden. The description adds nothing about the birth-data vs. pre-computed-chart union, the options object, or field/precision compaction. Baseline 3 is appropriate when the schema does the heavy lifting.

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 and resource ('render' a 'bi-wheel') and explains the layout: an inner natal ring plus an outer transit (or progression) ring. 'Two concentric wheels' implicitly distinguishes it from tri-wheel and single-wheel siblings, though it never names those alternatives explicitly.

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 guidance on when to choose this over astroway_render_tri_wheel, astroway_render_composite, or astroway_render_wheel_western, nor on when a bi-wheel is the right visualization. The '(or progression)' aside hints at a use case but gives no selection criteria.

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