monitoring_custom_metrics

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

No annotations are provided. The only behavioral hint is the '[SAFE]' tag, which suggests it is non-destructive, but it is not part of annotations. No other behaviors (e.g., authentication, rate limits, data volume) are disclosed.

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 very short (one sentence), which is concise but lacks necessary detail. It could be restructured to include more information without becoming verbose.

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 explain what is returned. It does not. Given the complexity of Prometheus querying, the description is insufficient for an agent to use the tool correctly.

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%, and the description adds no meaning to the parameters 'endpoint' and 'query'. The user is left guessing what the endpoint string should be (URL?) or what query format (PromQL?) is expected.

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 clearly states the action 'Query custom metrics' and the source 'Prometheus endpoint'. It distinguishes from other monitoring tools that query different sources (e.g., AWS CloudWatch). However, it does not explicitly differentiate from sibling tools like monitoring_alerts or monitoring_uptime_check.

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 provides no guidance on when to use this tool versus alternatives. There is no mention of context, prerequisites, or comparison to siblings like aws_cloudwatch_metrics.

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