Find Gaia DR3 sources within a given radius of sky coordinates (RA, Dec) using a cone search.
Cone search on Gaia DR3 catalog by coordinates and radius
| Name | Required | Description | Default |
|---|---|---|---|
| ra | Yes | Right Ascension in degrees (0-360) | |
| dec | Yes | Declination in degrees (-90 to 90) | |
| lang | No | Output language | en |
| radius | No | Search radius in arcseconds | |
| max_results | No | Maximum number of results |
Changes observed during successful MCP inspections.
v2.1.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must carry full behavioral burden. It doesn't state whether this is a read-only operation, how results are returned (fields, format), any rate limits, or pagination behavior. Only the basic operation is described.
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 single sentence is efficient and front-loaded with the key operation. It could be slightly more informative without losing conciseness, but it avoids waste.
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 no annotations and no output schema, the description is inadequate. It doesn't explain return values, result format, or limitations. With 5 parameters and 100% schema coverage, the agent can call it, but lacks behavioral context for correct interpretation.
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 coverage is 100%, meaning the schema already fully documents all 5 parameters including units and defaults. The description adds no parameter details beyond what the schema provides, so a baseline of 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?
The description states a specific verb (cone search), resource (Gaia DR3 catalog), and scope (by coordinates and radius). This clearly identifies the operation, though it doesn't explicitly distinguish from siblings like gaia_adql which offer a different query mode on the same catalog.
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?
No guidance is given on when to use this tool vs alternatives such as gaia_adql, vizier_query, or simbad_query. The description implies a spatial search but provides no context about use cases or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.