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 genuine context beyond that: the day-for-a-year methodology, the response contents (planets, houses, angles, aspects), and the 50-credit Tier 3 cost, which is useful for budgeting calls.

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 core meaning, followed by short structured metadata lines (group, endpoint, cost). Nothing is padded, though the return-value sentence is partly redundant with the output schema.

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 and full schema coverage, the description need not document return shape or parameter syntax, and it doesn't. The one real gap is routing guidance versus sibling progression tools, which matters given a toolset full of them.

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%, so the schema already documents the natal body, targetDate/targetTime/targetTzOffset, ayanamsa, houseSystem, and the compact fields/precision params in detail. The description adds nothing about parameters, 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?

States a specific verb (Calculate) and resource (secondary progressed chart) with the day-for-a-year technique and target-date scope, so the agent knows exactly what comes back. It does not differentiate itself from the very similar siblings astroway_prognostics_minor_progressions and astroway_prognostics_tertiary_progressions, so an agent choosing among progression types gets no help distinguishing them.

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?

There is no statement of when to use secondary progressions versus the minor/tertiary progressions siblings, nor any alternative or exclusion guidance. The description simply says what the tool computes; the agent must infer selection from the name.

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