Elasticsearch/OpenSearch MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states this is a read operation ('Returns information'), implying it's non-destructive, but doesn't cover aspects like authentication needs, rate limits, error conditions, or response format. For a tool with zero annotation coverage, this is a significant gap in transparency.

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 appropriately sized with two sentences: one stating the purpose and one documenting the parameter. It's front-loaded with the core functionality. The 'Args' section is clear but slightly verbose for a single parameter, keeping it from a perfect score.

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 moderate complexity (1 parameter, no output schema, no annotations), the description is minimally adequate. It covers the purpose and parameter but lacks details on usage context, behavioral traits, or output structure. Without annotations or output schema, more completeness would be beneficial, but it meets a basic threshold.

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?

The description includes an 'Args' section that documents the single parameter 'index' as 'Name of the index', adding meaning beyond the input schema (which has 0% description coverage). However, it doesn't provide details like format examples or constraints, so it partially compensates for the schema gap but not fully, warranting a baseline score.

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: 'Returns information (mappings, settings, aliases) about one or more indices.' It specifies the verb ('Returns'), resource ('indices'), and type of information returned. However, it doesn't explicitly differentiate from siblings like 'list_indices' or 'get_document', which would require a 5.

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 no guidance on when to use this tool versus alternatives. It doesn't mention siblings like 'list_indices' (which might list index names without details) or 'get_document' (which retrieves specific documents), leaving the agent without context for tool selection.

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