Elastic 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. It states the tool retrieves a document but doesn't disclose behavioral traits such as error handling (e.g., what happens if the ID doesn't exist), performance characteristics (e.g., speed, limitations), or security aspects (e.g., authentication needs). This leaves significant gaps for a read operation.

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 a single, clear sentence that efficiently conveys the core functionality without unnecessary words. It's front-loaded with the main action ('Retrieve'), making it easy to scan and understand quickly.

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 (3 parameters, no output schema, no annotations), the description is insufficient. It lacks details on return values (e.g., document format, error responses), usage context (e.g., part of a document database system), and behavioral expectations, leaving the agent with incomplete information for reliable invocation.

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 100%, so the schema already documents all parameters (index, id, _source). The description adds minimal value beyond the schema by implying the tool uses an ID for retrieval, but it doesn't explain parameter interactions (e.g., how _source affects output) or provide examples. This meets the baseline for high schema coverage.

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 action ('Retrieve') and resource ('a specific document by its ID from an index'), making the purpose immediately understandable. However, it doesn't explicitly differentiate from sibling tools like 'search' or 'get_index', which might also retrieve documents or index information, so it doesn't reach the highest 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?

The description provides no guidance on when to use this tool versus alternatives like 'search' (for querying documents) or 'get_index' (for index metadata). It mentions retrieving by ID but doesn't clarify prerequisites (e.g., needing a valid index and ID) or exclusions (e.g., not for bulk retrieval).

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