es_list_indices

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

With no annotations, the description carries the full behavioral burden. It does disclose the underlying endpoint ('GET /_cat/indices') and the return fields, which implies a read-only operation, but it omits permissions, failure behavior, and whether the pattern supports wildcards or regex.

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?

Two compact clauses with the operation front-loaded and no wasted wording. The endpoint note adds useful context without bloat.

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 two-parameter read tool, the description covers the operation and return metrics, but it leaves the required 'connection' parameter undocumented and does not clarify pattern syntax. Given no annotations and no output schema, that is adequate but with clear gaps.

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 0%, so the description must compensate fully. It only indirectly explains the 'pattern' parameter via 'matching a pattern' and says nothing about the required 'connection' parameter, leaving half the inputs undocumented.

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 and resource ('List indices') plus scope ('matching a pattern') and return contents ('health, doc count and store size'). It does not explicitly differentiate from siblings like es_search or es_cluster_health, but the purpose is clear enough to select the tool.

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?

Usage is implied: use this when you need to list Elasticsearch indices. However, the description gives no explicit when-to-use guidance, no exclusions, and never mentions alternatives such as es_request or es_search.

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