Elasticsearch/OpenSearch MCP Server

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 states the action ('Creates or updates') but fails to describe key traits like whether this is idempotent, what happens if the ID is omitted, permission requirements, or error conditions. This leaves significant gaps for a mutation tool.

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 front-loaded with the core purpose in the first sentence, followed by a parameter list. It avoids unnecessary fluff, but the parameter section could be more integrated into the flow rather than a separate block, slightly affecting structure.

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 complexity (mutation tool with 3 parameters, no annotations, no output schema, and 0% schema coverage), the description is incomplete. It lacks details on behavior, error handling, return values, and how it differs from siblings, making it inadequate for safe and effective use by an agent.

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 schema provides no param descriptions. The description lists parameters with brief notes ('Optional document ID'), adding some semantics beyond the schema. However, it doesn't explain the format of 'document' data or constraints on 'index', only partially compensating for the coverage gap.

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 verb ('Creates or updates') and resource ('a document in the index'), making the purpose specific and understandable. However, it doesn't explicitly differentiate from siblings like 'create_index' or 'update_document' (if such a tool existed), which prevents a perfect score.

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 provided on when to use this tool versus alternatives like 'create_index' for index creation or 'get_document' for retrieval. The description lacks context about prerequisites, such as whether the index must exist, or exclusions, leaving the agent without usage direction.

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