Retrieve OpenSearch indices with their health, document count, and size. Optionally filter by name pattern to focus on specific index groups.
List indices in the cluster with their health, doc count, and size.
Args: pattern: Optional index name pattern to filter (e.g. 'filebeat-', 'logs-').
| Name | Required | Description | Default |
|---|---|---|---|
| pattern | No |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the behavioral disclosure burden. It clearly implies a read-only listing operation and states what information is returned, but it does not mention permissions, pagination, index-access restrictions, or the behavior when no pattern is supplied. This is adequate but not deeply transparent.
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 compact and front-loaded, with the core purpose stated in the first sentence. The parameter note is minimal, and every sentence adds useful information without redundancy.
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?
For a simple tool with one optional parameter and a separate output schema, the description is nearly complete. It covers the main purpose, the return fields, and the only parameter. The main gap is the absence of routing guidance against similar sibling tools, but this is a minor omission for such a low-complexity operation.
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 input schema has 0% description coverage and only provides the parameter name and default null. The description compensates fully by explaining that the pattern is optional, is an index name filter, and includes concrete wildcard examples ('filebeat-*', 'logs-*'), which adds meaningful guidance beyond the schema.
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 a specific verb ('List'), a clear resource ('indices in the cluster'), and the exact returned information ('health, doc count, and size'). This distinguishes it from sibling tools like list_aliases, cluster_health, and search without needing to inspect their schemas.
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 about when to use this tool versus alternatives such as search, count, list_aliases, or get_index_mapping. There are no explicit conditions, exclusions, or references to sibling tools, so the agent must infer usage solely from the tool name.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.