list_indices

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

Annotations already communicate readOnlyHint=true and destructiveHint=false, so the description does not need to restate safety. It does add useful behavioral context around pattern matching and the inclusion of aliases/data streams, but it does not mention pagination, pattern syntax limitations, or the potential breadth when pattern defaults to '*'.

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?

A single, front-loaded sentence covers the action, scope, filtering mechanism, and included stats without redundant words. Every phrase adds meaningful information.

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 read-only, two-parameter inventory tool with an output schema, the description is largely sufficient. It could be more complete around the pattern matching semantics, but the annotation safety profile and schema defaults reduce the risk of calling this tool incorrectly.

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 for explaining both parameters. It references 'pattern' and 'aliases' but does not explain wildcard syntax, the meaning or effect of include_aliases, or how the default values influence behavior.

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 uses a specific verb ('List') and identifies concrete resources: indices, data streams, and aliases. It also communicates the returned information (doc counts and store size), which separates it clearly from sibling tools like cat_nodes, get_mapping, and index_health.

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 discovery/inventory use by saying 'matching a pattern', but it does not explicitly state when to prefer this tool over siblings such as alias_actions, cat_nodes, or index_health. There are no exclusions or alternative routing hints.

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