Get Prometheus metrics

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

Annotations already declare readOnlyHint and openWorldHint, covering safety. The description adds meaningful context about the output format (Prometheus) and source semantics, but does not disclose details like response size, pagination, or rate limits. This is acceptable for a read-only fetch tool.

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, front-loaded sentence with zero redundant words. It immediately states the action, format, and purpose, then efficiently explains the parameter options.

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 simple one-parameter read-only tool, the description fully covers what it does, when to use it, and how to select the source. 'Prometheus-format' implies a standard output structure, compensating for the absence of an output schema. No gaps remain.

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 schema alone lists enum values 'cdn' and 'cloud_storage' with minimal description. The tool description enriches these by explaining what each value represents ('Anycast CDN' and 'Cloud Store'), which goes beyond the schema and aids correct parameter selection.

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 tool's function with a specific verb ('Fetch') and resource ('Prometheus-format metrics'), and explicitly maps the two source values to distinct services. This distinguishes it from sibling metrics tools like get_cdn_metrics and get_bucket_metrics.

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?

Provides clear use context ('monitoring dashboards') and explains how to choose the source parameter. It does not explicitly compare against alternative metrics tools, but the intended scenarios are evident.

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