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 full burden. 'Search for documents' implies a read operation but doesn't disclose behavioral traits like whether this is paginated, what format results return, authentication requirements, rate limits, or error conditions. The description mentions parameters but doesn't explain search behavior beyond the basic action.

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 concise with only 3 lines. The first sentence states the purpose, followed by a parameter section. However, the structure with 'Args:' formatting is somewhat redundant since parameters are already documented in the schema, and the content is too sparse to be truly helpful.

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 2 parameters with 0% schema coverage, no annotations, no output schema, and nested objects in parameters, the description is incomplete. It doesn't explain what the tool returns, how search results are structured, what the 'body' object should contain, or provide context about the document system. For a search tool with complex parameters, this leaves significant gaps.

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 0%, so the description must compensate. It lists 'index: Name of the index' and 'body: Search query' which adds minimal meaning beyond parameter names. However, it doesn't explain what an 'index' is in this context, what format the 'body' query should take, or provide examples. With 2 parameters and no schema descriptions, this is inadequate compensation.

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 'Search for documents' which is a tautology of the tool name 'search_documents'. It doesn't specify what kind of documents, what system they're in, or how the search works. While it mentions the verb 'search' and resource 'documents', it lacks specificity and doesn't distinguish this from potential sibling tools like 'get_document' or 'index_document'.

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. With sibling tools like 'get_document' (retrieve specific document), 'index_document' (add document), and 'delete_by_query' (delete via query), there's no indication of when search is appropriate versus direct retrieval or other query-based operations. The description doesn't mention prerequisites like needing an existing index.

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