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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered. The description adds minimal behavioral context beyond that—just 'summary and recent series' which hints at the return shape but not details like pagination or freshness. Given the annotations, a 3 is fair; it adds a little but not much.

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 a single, concise sentence, front-loaded with the verb and resource. It is not bloated, though it could be slightly more detailed without losing conciseness. It earns its place, but a bit more behavioral or usage guidance would improve it.

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?

The output schema exists, so return value explanation is not needed. However, given the tool's complexity (2 params, one with a limit), and the existence of many sibling index/rate tools, the description is slightly sparse. It doesn't explain what 'recent series' means or how it relates to other index tools, so an agent might underuse it. It is complete enough for basic calls but not for nuanced selection.

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 50%: indexId is described with examples, but limit is not described in the schema. The description doesn't add meaning to limit at all, so it relies on the schema's type/constraints. For indexId, the schema already gives a description, so the tool description doesn't add extra value. 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 states a clear verb ('Return') and resource ('SwitchWize index dataset summary and recent series'), which is specific enough. However, it does not differentiate from siblings like get_bank_gap_index, which could be confused with an index dataset. The name includes 'index' but the description doesn't clarify that this returns a summary of many indices or a specific one.

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 does not provide any context on when to use this tool versus alternatives. It implies a read-only retrieval, but with siblings like get_bank_gap_index and get_rate_freshness, an agent would need more guidance on when to pick this one. No exclusions or alternative names are mentioned.

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