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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so safety is covered. The description adds genuinely useful behavior: it returns twelve day and twelve night hours counted from sunrise with clock times for the place plus the currently running hour, and it states that birth details are not required, which prevents unnecessary prompting.

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?

Front-loaded with the trigger condition, then the return shape, then prerequisites. Example utterances and the 'needs the town / needs no birth details' clauses each remove real ambiguity rather than padding.

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?

No output schema exists, so the description carries the return contract and it does so adequately: hour counts, sunrise-based counting, clock times, and the current hour. Required parameter, default for date, and the no-birth-details constraint are all covered.

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%, so baseline is 3, but the description adds meaning beyond the schema: it instructs the agent to ask for the town when the user has not supplied one, and it explicitly rules out birth details as inputs. That reduces the risk of wrongly soliciting extra parameters.

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: returns planetary hours (hora) for a day and place, twelve day and twelve night hours from sunrise. Clearly separable from siblings like daily_panchang, current_dasha, or moon_today, all of which answer different astrological questions.

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?

Gives explicit trigger conditions with four realistic utterances ('planetary hours today in London', 'what planetary hour is it', 'when is the Venus hour today'), which is strong context for selection. It does not name an alternative sibling or state when-not to use it, so it stops short of a 5.

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