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

No annotations are provided, so the description carries the full burden. It explains the output format and relationship to sky_view, but does not mention side effects, performance, or data volumes. Given the tool's read-only nature, it is fairly transparent.

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, front-loaded with purpose, followed by output details and sibling relationship, then use cases. Every sentence is informative with no redundancy or filler.

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 11 parameters and no output schema, the description does a good job explaining what is returned (timeline fields, celestial pole, rotation), but lacks detailed output structure or potential limitations beyond frame count. Still, it provides sufficient context for an agent to understand the tool's utility.

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 73%. The description adds overall semantic context (same place, aim, lens stepped through time) that groups parameters and explains their role. This adds value beyond individual parameter descriptions.

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 it creates a time sequence of sky frames for animation, returns a compact per-frame timeline, and distinguishes itself from sky_view which provides full per-frame specs. It is specific and informative.

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 description explicitly mentions use cases (sunset-to-night transitions, star-trail planning, Moon-phase progressions) and implicitly tells when not to use it (for full pixel-accurate specs, use sky_view). This provides clear guidance.

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