Western Wheel (SVG)

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds that rendering is fully server-side, which is genuinely useful context, plus a cost line. However, it omits two material behaviors documented only in the schema: the input accepts either raw birth data or a pre-computed chart (1 credit vs 10), and options.format defaults to 'json' despite the tool being titled SVG.

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 sentences that front-load what is drawn and where it runs, followed by compact metadata lines (group, endpoint, cost). No filler, though the cost/tier line is structured metadata rather than descriptive value.

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 renderer with an output schema and strong annotations, the essentials — what is drawn, that it is server-side — are present. The main gap is the dual input mode and the json-vs-svg default, which an agent must discover from the schema; sibling differentiation against the bi/tri-wheel tools is also absent.

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?

The description contributes nothing about parameters — it never mentions the birth-data vs. pre-computed-chart union, the size/theme/bodies/showAspects options, or coordinate and timezone requirements. The schema itself carries deep inline documentation for timezone, labels, houseSystem and theme, which offsets the low top-level coverage, but the description does no work of its own here.

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 verb and resource — 'Render a Western natal wheel as SVG' — and enumerates the rendered layers (signs ring, houses ring, planets, aspect lines). The word 'Western' implicitly separates it from the Vedic east/north/south wheel siblings, but it never explicitly contrasts with astroway_render_bi_wheel or astroway_render_tri_wheel, which also draw Western-style wheels.

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?

'Pure server-side, no browser needed' implies a usage context (headless rendering) but gives no directive on when to pick this over the Western chart computation tool or the bi/tri-wheel renderers. No exclusions, prerequisites, or alternatives are stated; an agent must infer selection from the name alone.

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