chuk-mcp-celestial

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does an excellent job describing what the tool returns (altitude, azimuth, distance, etc.), interpretation of values (e.g., 'altitude > 0 means the planet is above the horizon'), and practical constraints ('Elongation < 10-15 degrees means planet is too close to the sun to see'). However, it doesn't mention potential limitations like computational complexity, error conditions, or rate limits, keeping it from a perfect score.

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 with clear sections (purpose, returns, args, tips, example) and every sentence adds value. However, at approximately 400 words, it's quite lengthy for a tool description. While all content is useful, some information in the 'Tips for LLMs' section could potentially be streamlined or moved to documentation, preventing a perfect score for conciseness.

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 the tool's complexity (6 parameters, astronomical calculations), no annotations, and no output schema, the description provides exceptional completeness. It explains what the tool does, when to use it, all parameter details, return data structure with field explanations, practical examples, and interpretation guidance. The example shows exactly how to invoke the tool and use the results, making this description self-contained and comprehensive.

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?

With 0% schema description coverage, the description fully compensates by providing comprehensive parameter semantics. Each of the 6 parameters is clearly explained with examples, valid ranges, and interpretation rules (e.g., 'timezone: Timezone offset from UTC in hours... When provided, the time parameter is interpreted as local time'). The planet parameter even lists all valid values (Mercury through Pluto), and date/time formats are specified with examples.

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: 'Get position and observational data for a planet at a specific time and location.' It specifies the verb ('Get'), resource ('position and observational data for a planet'), and scope ('at a specific time and location'), distinguishing it from sibling tools like get_earth_seasons or get_moon_phases. The detailed return data list further clarifies the exact information provided.

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 usage guidance with named alternatives and specific contexts. It states: 'Essential for planning astronomical observations and answering "where is [planet] tonight?" questions,' and includes practical tips like 'For "where is Mars tonight?", use time="21:00" with appropriate timezone.' This clearly indicates when to use this tool versus other astronomical tools in the sibling set.

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