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

Annotations mark it non-read-only and non-destructive, and the description adds behavior the annotations do not cover: the 5,000-credit Tier 7 charge (~50% of a free monthly budget) and the requirement to confirm with the user first. It does not mention rate limits, auth needs, or render latency, so it is strong but not exhaustive.

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 front-loaded sentences carry the purpose and computational scope, followed by compact structured tags for group and cost. No sentence is filler; the cost warning is placed where it will be seen before invocation.

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?

Output schema exists so return values need no explanation, and the description covers the report content, cost, and confirmation requirement for a 6-parameter tool. The only visible gap is the title's mention of 'PDF or HTML' versus the description's PDF-only wording, leaving the output-format choice ambiguous.

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 only 50%, and the description compensates on just one parameter — it explains the `year` default (next calendar year) and defines the report's computational scope. The other parameters (fields, precision, language, whitelabel, chart) get no added meaning beyond the schema, leaving real gaps at this coverage level.

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 (Render) and resource (year-ahead transit calendar PDF), then goes further to define the exact content: major aspects of Mars–Pluto to natal positions at a 0.5° orb. This clearly distinguishes it from narrative-report siblings like astroway_reports_ai_year_ahead_narrative, which produce prose rather than a month-grouped calendar.

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?

Gives concrete usage context: defaults to next calendar year when `year` is omitted, and explicitly instructs the agent to confirm with the user before invoking because of the 5,000-credit cost. It does not name an alternative tool or state when-not-to-use, so it stops short of a 5.

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