rds_metrics

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

With no annotations, the description carries the full burden, and it does disclose the read-only nature and the CloudWatch data source plus the metric set returned. However, it omits auth/region requirements and any pagination or failure behavior an agent might need before invoking.

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?

Three tight sentences with the purpose and metric list front-loaded and no filler. The noisy-neighbour framing and read-only note both earn their place, though the metric enumeration is somewhat list-heavy.

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 read-only metric-snapshot tool with no output schema and no annotations, the description covers the source, the operation, the returned metrics, and the primary use case. It is nearly complete, missing only return format and required permissions.

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 100%, so the schema already documents region, account, db_instance, and window_hours. The description only restates db_instance as the DB instance identifier, adding no syntax or format detail beyond the schema, so the baseline 3 applies.

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 specific verb (Snapshot) and resource (an RDS instance's health from CloudWatch) and enumerates the exact metrics returned. It is clearly differentiated from query-oriented siblings like db_processlist and db_top_queries, though it doesn't name any sibling explicitly.

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?

It gives one strong usage cue — 'the first check for the shared-RDS noisy-neighbour case' — which tells the agent when to reach for it. But there is no guidance on when to use alternatives (e.g., db_top_queries or db_processlist) or any prerequisites, leaving usage only partially specified.

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