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

The description frames the tool purely as data retrieval ('Return ...'), yet annotations declare readOnlyHint=false and idempotentHint=false, so an agent cannot tell whether the call has side effects or produces differing results across invocations. The description does add the useful defaulting rule (today in UTC), but it discloses nothing about side effects or repeat-call behavior to reconcile the non-read-only annotation. Has an output schema, so return format need not be described.

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 sentences, front-loaded with the resource definition, followed by the defaulting rule. No filler, no repetition of the title.

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?

The output schema covers the return value and the default behavior is stated, so the basics are present. But with 0% schema description coverage across three parameters, omitting 'language' entirely and giving no date format leaves an agent guessing on inputs for a tool whose annotations also raise side-effect questions.

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 0%, so the description must carry the load; it explains that location_timezone is an IANA timezone and that date defaults to today in UTC, which adds real meaning beyond the bare schema defaults. It never mentions the 'language' parameter at all, and gives no accepted date format, leaving a third of the surface undocumented in both places.

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+resource: it returns sidereal planetary signs and nakshatras (gochar/transit sky) for a date and timezone. Domain terms are clarified parenthetically, so the resource is unambiguous. It does not differentiate itself from the closest sibling, get_transits_to_chart, which also concerns planetary positions, leaving the agent to infer that this is a chart-independent sky snapshot.

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?

Usage is implied by 'now'/'current gochar' and the defaulting behavior ('defaults to today's date in UTC'), so an agent can infer this is a snapshot call rather than a chart-based analysis. However, it names no alternative and gives no conditions for choosing it over get_transits_to_chart or today_for_me, so the routing decision 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.