Bi-Wheel (SVG)

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description usefully adds the endpoint and the 10-credit price. However, it never mentions the dramatically cheaper path (1 credit) when both charts are supplied as precomputed data, nor that the default output format is json despite the 'SVG' title – both are behavioral traits an agent would want before calling.

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 short sentences with the layout described up front, followed by compact metadata lines; nothing is padded. The bracket block is slightly utilitarian but each entry (group, endpoint, cost) is informative for an agent.

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 needn't be explained, and the visual intent is clear. But for a complex tool with two input modes, a 10x credit difference between them, and several ambiguous options, the description leaves gaps that the agent must discover in 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 description coverage is reported at 0% for the single 'body' parameter, so the description carries the burden – and it says nothing about parameters. It omits the two mutually exclusive input shapes (birth data vs. precomputed chart objects), the default format=json, and the outerLabel/crossAspects options, all of which materially change the call.

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+resource: two concentric wheels with inner natal and outer transit/progression ring, plus 'standard bi-wheel layout'. An agent can picture the output without opening the schema. It does not name the near neighbours (tri-wheel, composite, western wheel) that an agent must choose between, so it stops short of full 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: nothing says to pick this over astroway_render_tri_wheel or astroway_render_composite, nor when a transit outer ring beats a progression one. The only bracketed lines are group, endpoint and cost, which are metadata rather than selection criteria.

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