index_health

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

Annotations already mark it read-only and non-destructive, so the description doesn't need to restate that. It adds behavioral value by enumerating exactly which metrics are returned and by implying the default is a wide search until an index pattern narrows it. No contradictions with annotations.

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 efficient sentences: the first front-loads the tool's purpose with a metric list, the second gives the key usage hint. No repetition of annotations or schema, and each sentence carries content.

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?

With an output schema present and read-only annotations, the description covers the main purpose and the only core parameter. It misses explicit guidance on default scope (no pattern means all indices), the effect of include_settings, and when to prefer cluster_health or cat_nodes over a per-index health report.

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?

Input schema has 0% field description coverage, so the burden falls on the description. It clarifies the 'index' parameter (an index pattern narrows the scope) but says nothing about 'include_settings' (whether it toggles settings details in the output). This is a meaningful gap for an agent choosing parameters.

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?

States a specific verb+resource: reports per-index health and size with an explicit metric set (status, docs, store size, primaries/replicas, segments, refresh/merge stats, throughput). It is clearly distinguishable from many siblings by content, though it doesn't explicitly name the closest alternative (cluster_health) — hence not a 5.

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 only usage hint is 'Pass an index pattern to narrow it down,' which explains the index parameter rather than when to choose this tool over siblings like cluster_health or cat_nodes. No explicit when-to-use, exclusions, or alternative routing is given.

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