describe_index

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Without annotations, the description should explicitly note that the tool is read-only. It describes the output (mappings, settings, statistics) but does not mention side effects, permissions, or that it is a safe 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 very concise with a clear purpose, followed by structured Args and Returns sections. Every sentence adds value and is front-loaded.

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 simplicity and presence of an output schema, the description covers purpose, input, and output. Lacks usage guidance but is otherwise complete for a retrieval tool.

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 sole parameter 'index' is described as 'Name of the index to describe,' adding clear meaning beyond the schema (which only has a title). This is sufficient for a simple parameter.

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 retrieves detailed information about an index, specifying mappings, settings, and statistics. This distinguishes it from sibling tools like get_mappings and get_index_stats which focus on specific aspects.

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 explicit guidance on when to use describe_index versus alternatives like get_mappings or get_index_stats. The description implies it is for a comprehensive overview but does not state exclusions or context.

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