Yesterday's Sky

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful context—credit cost (10 credits, Tier 1) and endpoint—but does not describe what the tool returns or any special behavior beyond what the annotations imply.

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 description is extremely compact and front-loads the method reference while using bracket tags for group, endpoint, required fields, and cost. It is efficient and waste-free, though its terseness borders on under-specification rather than helpful brevity.

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 values need not be explained. However, for a 13-parameter tool with only 23% schema coverage, the description does not clarify the tool's actual purpose or explain how to use the many optional inputs, making it insufficient for correct invocation.

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 only 23%, so the description needs to compensate, yet it merely repeats the four required parameters already listed in the schema's required array. Optional parameters (ayanamsa, timezone, cosmogram, houseSystem, timezoneOffset, etc.) are not mentioned at all, leaving most of the 13-parameter surface unexplained.

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 technique ('Forrest 2008 past-life method') but never states what the tool actually computes or returns. It does not use a clear verb+resource construction and gives an agent no way to distinguish this from the many other evolutionary-astrology siblings beyond a citation.

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 guidance on when to use this tool versus the numerous sibling evolutionary tools (soul_types, nodal_axis_detail, pluto_natal_condition, skipped_steps, etc.). The only selection hints are the group tag and required fields, which are insufficient for an agent to choose correctly.

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