Generate Stellaforge Birth-Chart Poster (PDF or HTML)

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

Adds substantial information beyond the annotations (readOnlyHint=false, idempotentHint=false, destructiveHint=false): it discloses the credit cost tier, the routing quirk that `style` is read from the BODY not the query string, and that output is fully deterministic with no AI. It does not spell out side effects of a repeated call (billing each time, given idempotentHint=false) or whether the generated asset is stored/retrievable.

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?

Front-loads the deliverable and output contents, then moves to options, format behavior, and the critical body-vs-query caveat. Dense and mostly waste-free, though the parenthetical enumeration of wheel elements is longer than an agent needs for tool selection.

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?

With an output schema present, return values need no explanation, and the description covers styles, white-labeling, i18n, format switch, cost, and the body/query quirk. The main gap is guidance on choosing this over the other report/render siblings, plus no note that the required `chart` payload is the operative input.

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 low (25%), but the description supplies meaning for three of the four top-level parameters: the three `style` values with their visual character, `whitelabel` white-labeling, and `language` i18n, plus the non-schema `format` switch. The required `chart` parameter is not mentioned in the description at all, relying entirely on the (admittedly rich) nested schema description.

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 and artifact ('Render a data-rich, print-ready natal chart poster') and enumerates the exact contents of the output (wheel, placements table, balance bars, aspects). It is distinguishable from the pure-render siblings (astroway_render_wheel_western) and narrative reports (astroway_reports_natal) only by inference from 'poster' plus 'deterministic, 0 AI', not by an explicit comparison.

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?

Provides real operating context: PDF is the default with `?format=html` returning HTML, and the premium cost (5,000 credits, ~50% of free monthly budget) with an instruction to confirm with the user first. It never states when to prefer this over a sibling such as astroway_reports_natal or astroway_render_wheel_western, so selection between them is left to inference.

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