list_visible_planets

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

No annotations are provided, so the description carries the full burden, and it does disclose the key semantic caveat: above-horizon visibility does not imply dark-sky or telescope conditions, plus the required inputs. It stops short of stating whether results are cached or what _meta contains, which is minor for a pure computation.

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 purpose followed by clearly labeled Use when / Do not use when / Requires / Follow-up / Args / Returns sections makes it skimmable, and nearly every line earns its place. The Returns block partially repeats what the output schema already declares, a small redundancy.

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?

Given four required parameters, zero annotation coverage, and an output schema that exists, the description supplies everything an agent needs: preconditions (coordinates, time, timezone), the visibility semantics, sibling routing, and a brief return shape.

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 compensate, and it does: all four parameters are documented with units (degrees for lon/lat), an explicit time string format "YYYY-MM-DD HH:MM:SS", and 'IANA timezone string' for time_zone. Only lat/lon valid ranges are left implicit.

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 and resource ('Get a list of solar system planets') with a clear scope qualifier ('currently visible, above horizon'), and the usage/exclusion lines separate it from siblings like get_celestial_rise_set and get_best_stargazing_plan.

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?

Explicit 'Use when' and 'Do not use when' clauses name the exact conditions that select or exclude this tool, and the Follow-up line routes the agent to the correct siblings (get_celestial_pos, get_celestial_rise_set, plan_stargazing_session) with the condition for each.

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