Tri-Wheel (SVG)

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

Annotations already declare readOnlyHint, idempotentHint and non-destructive behaviour, so the safety profile is covered. The description adds genuinely useful operational context — the POST endpoint and a 10-credit (Tier 1) cost — but says nothing about what the response contains or that output format is driven by options.format, despite the title implying 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 plus bracketed metadata, front-loaded with the visual composition before the operational tags. Nothing is padded, though the 'advanced forecasting visuals' clause is filler relative to a real usage rule.

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-value detail is not required, and the rich nested birth-data schema covers the inputs. However, for a four-parameter tool whose semantics hinge on which chart goes in which ring, the description leaves the middle/outer mapping and format behaviour to inference.

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?

With 75% schema description coverage and extensive nested field documentation, the schema carries most of the meaning. The description's only parameter content is the required list (natal, middle, outer), which merely restates the schema's required array and never clarifies which layer is the progressed vs transit wheel — a notable gap given the tool's whole premise.

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 artifact (three concentric wheels) and enumerates its three layers (natal, progressed, transit), so an agent can tell it apart from a single wheel or bi-wheel render at a glance. It stops short of naming the nearest sibling (astroway_render_bi_wheel) or mapping 'middle'/'outer' explicitly onto progressed/transit.

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?

Only 'Used for advanced forecasting visuals' is offered as guidance, which is a tagline rather than a selection rule. There is no statement of when to choose this over astroway_render_bi_wheel, astroway_render_wheel_western, or astroway_prognostics_transits, and no exclusions.

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