Get Sun Position

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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: computation is done locally with suncalc and declination/right ascension are approximate, which tells the agent how much to trust the values.

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 short sentences, front-loaded with the purpose and the returned values, then the usage line and caveat. No filler and no repetition of what the schema already says.

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?

With a rich output schema, full parameter coverage, and strong annotations, the description only needs to add what those fields cannot. It does that with the local-computation note and the approximation caveat; the remaining omission (date/time defaults, timezone) is already documented in the schema.

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 100%, so the schema already documents date, time, latitude, longitude, and response_format in detail. The description adds only the vague "azimuth ... as rendered here" convention note and the approximation caveat, which barely extends the schema. Baseline 3 is appropriate.

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 the sun's position") and enumerates the returned quantities: azimuth, altitude, declination, right ascension. It is clearly distinct from siblings like astro_get_sun_times or astro_get_next_sun_event, but it never names or contrasts those siblings explicitly.

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?

"Use for: shadow/lighting analysis, solar exposure" gives concrete contexts where this tool is the right pick, which is more than implied usage. However, it offers no exclusions or pointers to the related sun-time tools, so an agent must still infer the boundary cases.

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