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

Annotations already indicate readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description's 'Computes' aligns with these non-destructive, read-only semantics and adds output context (returns values in UTC). No contradiction exists. The description does not explicitly mention side effects, but the annotations cover that, so the bar is met with the added output detail.

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 well-structured with distinct sections: main purpose, workflow, input contract, and do-not-confuse. Despite containing multiple sections, it remains focused and each part serves a clear purpose. No redundant or fluffy language; it is compact while conveying necessary details.

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 description covers what the tool computes, output specifics (UTC), input constraints, exclusions from similar tools, and even provides a link to the full output/error contract. Given the tool's moderate complexity (nested location object with optional parameters), this is a complete context for an agent to decide and call it correctly.

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 100% (all fields described). The description's INPUT CONTRACT adds meaningful details beyond the schema: 'date must be YYYY-MM-DD', 'lat/lon bounds are validated locally', 'Upstream rejects calendar dates outside 1900–2100', and 'timezone defaults to Asia/Kolkata'. These clarifications enhance parameter understanding, making the semantics strong.

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 clearly states the tool computes Panchanga elements for a single calendar date and geographic location, listing the returned values (tithi, vara, nakshatra, yoga, karana, end times). It also explicitly distinguishes itself from siblings: 'DO NOT CONFUSE WITH: asterwise_get_yogas — natal chart yogas... asterwise_get_panchanga_calendar — whole-month daily rows, not a single day.' This provides unambiguous purpose and differentiation.

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?

The workflow section ('BEFORE: None', 'AFTER: asterwise_get_choghadiya') gives sequencing context, and the 'DO NOT CONFUSE WITH' section tells when not to use this tool. However, it lacks a direct statement like 'Use this when you need a single-day Panchanga for a location,' relying instead on exclusions to imply the usage case. Thus it is clear but could be more explicit.

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