chuk-mcp-celestial

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

With no annotations provided, the description carries full burden and delivers substantial behavioral context. It explains what happens when no eclipse is visible (returns specific description text), defines magnitude thresholds for eclipse types, specifies visibility conditions (sun altitude > 0), and describes the return format (GeoJSON Feature with specific properties). However, it doesn't mention error handling for invalid inputs or performance characteristics like rate limits.

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 and appropriately sized. It begins with a clear purpose statement, follows with detailed calculation behavior, then provides organized sections for Args, Returns, Tips, and Example. Every sentence adds value - no redundant or vague phrasing. The information is front-loaded with the core functionality stated first.

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?

For a tool with 4 parameters, 0% schema coverage, no annotations, and no output schema, the description provides excellent coverage of inputs, behavior, and return format. It explains what the tool calculates, parameter constraints, interpretation of results, and includes a practical example. The only minor gap is lack of explicit error handling documentation for edge cases like invalid date formats.

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?

Given 0% schema description coverage, the description fully compensates by providing detailed parameter semantics beyond the bare schema. It explains each parameter's purpose, format constraints (date format, valid ranges for latitude/longitude/height), and the height parameter's default value. The example demonstrates proper parameter usage with realistic values.

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's purpose with specific verbs ('Get local solar eclipse circumstances', 'Calculates whether a solar eclipse is visible') and resources ('for a specific date and location'). It distinguishes from siblings by focusing exclusively on solar eclipse calculations for a given date/location, unlike get_solar_eclipses_by_year (year-based) or get_sun_moon_data (general sun/moon data).

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 provides explicit guidance on when to use this tool versus alternatives: 'Use get_solar_eclipses_by_year first to find eclipse dates' establishes a clear workflow dependency. The 'Tips for LLMs' section includes exclusion criteria ('If description is "No Eclipse at this Location", the eclipse isn't visible here') and prerequisites ('altitude must be > 0 for eclipse to be visible').

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