Tertiary Progressions

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely useful operational context — the POST endpoint and the 50-credit / Tier 3 price — but says nothing about what the result contains or how the converse flag alters output; with an output schema present that omission is tolerable.

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?

The core sentence is front-loaded and dense, and the bracketed Group/Endpoint/Cost lines are scannable metadata rather than prose padding. Nothing is redundant.

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 annotations, a fully documented input schema and an output schema, the definition covers what an agent needs to invoke it. It only lacks a pointer to when this technique is preferred over its progression siblings.

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 100%, and the nested body schema documents date/time/coordinates/timezone/houseSystem/ayanamsa in detail. The description only alludes to the target date and the converse option, adding no semantics beyond the schema, so the baseline 3 applies.

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?

Names a specific verb and technique (Calculate tertiary progressions) and defines the rate in parentheses ('day-for-a-lunar-month'), which distinguishes it from the plain and minor progression siblings. It doesn't explicitly contrast itself with astroway_prognostics_progressions or astroway_prognostics_minor_progressions, so the agent must infer the difference from astrological knowledge.

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 usage-adjacent facts are given: it takes a target date and 'Supports converse direction.' There is no statement of when to choose tertiary over secondary/minor progressions or primary directions, and no prerequisites or exclusions are mentioned.

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