Get index mappings

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

With no annotations, the description carries the behavioral disclosure burden. It states the read-only retrieval behavior and adds the important fallback to _field_caps when credentials cannot read _mapping directly. It does not describe error cases or output shape, but the disclosed behavior is honest and useful.

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?

Three sentences, each earning its place: purpose, usage advice, and fallback behavior. Information is front-loaded and there is no filler.

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 low-complexity tool with one well-documented parameter and no output schema, the description is nearly complete. It explains what the tool returns, when to call it, and how it handles credential limitations. Minor missing detail is the exact response structure of the fallback.

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 schema already covers the single parameter fully with a description and example. The tool description adds context about mappings but not additional parameter-level syntax or constraints, so baseline 3 is appropriate.

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 names a specific verb, resource, and scope: 'Return the field mappings for an index or index pattern.' This clearly differentiates it from sibling tools like es_search, es_count, and es_list_indices.

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 gives explicit usage guidance: 'Read this before writing a query so field names and types are correct.' It does not spell out when-not-to-use or name alternative tools, but the intended context is clear.

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