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 of behavioral disclosure. It mentions the tool 'explains' shard allocation issues, but does not specify whether this is a read-only operation, what permissions are required, how the explanation is formatted, or if it has side effects. For a diagnostic 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 a single, direct sentence that efficiently conveys the tool's purpose without unnecessary words. It is front-loaded with the core functionality, making it easy to understand quickly, and every part of the sentence contributes meaningfully.

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 diagnostic nature, 3 parameters, no annotations, and no output schema, the description is minimally adequate but lacks completeness. It explains what the tool does but does not cover behavioral aspects like response format, error handling, or usage constraints, which are important for a tool that explains system states.

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 does not mention any parameters, but the input schema has 100% description coverage, with clear documentation for 'index', 'shard', and 'primary'. Since the schema fully describes the parameters, the baseline score is 3, as the description adds no additional semantic context beyond what the schema provides.

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 with a specific verb ('explain') and resource ('shard'), specifying what it explains ('why a shard is unassigned or why it remains on its current node'). It distinguishes itself from sibling tools like 'get_shards' or 'cluster_health' by focusing on diagnostic explanations rather than status retrieval.

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 implies usage in troubleshooting scenarios involving shard allocation issues, but it does not explicitly state when to use this tool versus alternatives like 'get_shards' for status checks or 'cluster_health' for broader diagnostics. No exclusions or prerequisites are mentioned, leaving some ambiguity in context.

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