get_cache_metrics

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

Annotations already disclose read-only and non-destructive behavior. The description adds valuable context about the implementation: data is 'materialized' and the operation avoids scanning event JSON, indicating a fast, constrained read path. This goes beyond annotations without contradicting them.

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 sentence, front-loaded with the action, and contains no redundant information. Every phrase adds context about the tool's purpose and efficiency, making it highly concise and well-structured.

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 tool has no output schema, so the description should clarify the return value structure. It mentions 'cold/warm cache telemetry and target status' but does not detail the specific metrics or formatting. Parameter semantics are also left to the schema, leaving some gaps, though the simple scope and annotations make it adequate for basic 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?

The input schema has zero description coverage for its 3 parameters, and the tool description does not explain what 'model', 'gateway', or 'window_seconds' mean or how they affect the query. The property names are somewhat self-explanatory in a cache metrics context, but the description adds no semantic value and fails to compensate for the missing schema descriptions.

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 the specific verb 'Return' and identifies the resource as 'materialized cold/warm cache telemetry and target status'. It distinguishes the tool from others by explicitly stating 'without scanning event JSON', which differentiates it clearly from sibling tools like get_events.

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 this tool is for efficiently retrieving pre-aggregated telemetry rather than scanning raw events, which gives a clear context for when to use it. However, it does not explicitly name alternatives or state when not to use it, so it lacks exclusions.

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