Get metrics history retention setting

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description does not need to restate safety. The description adds no behavioral context beyond the name - it doesn't describe what format the retention setting is returned in, whether it is a global or per-host setting, or any side effects (though annotations imply none). With annotations covering the read-only nature, the description's lack of additional behavioral detail is acceptable but not helpful. It does not contradict annotations, so not a 1.

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 short sentence, which is appropriately concise for a tool with no parameters. It is not bloated, but it is under-specified rather than efficiently concise - the sentence restates the name, so it is technically brief but not adding value. For a zero-param read tool, brevity is good, but the description could have added a snippet of context without losing conciseness.

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 no-parameter getter with read-only annotations and no output schema, the description is arguably complete enough for an agent to understand the basic action. However, it lacks any context about the returned value (e.g., format, units, or whether it's global), which could be important for an agent deciding if this tool meets its need. Given the simplicity, a 3 is fair - it meets minimum viability but leaves room for improvement.

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?

There are zero parameters, and the input schema is an empty object with 100% coverage (vacuously). Since there are no parameters to describe, the description doesn't need to add parameter semantics. The schema and context signals fully define the invocation - no arguments are required. Baseline 4 for zero-parameter tools is appropriate; there is no gap.

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?

Tautological: description restates name/title.

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?

There is no guidance on when to use this tool versus alternatives. The description does not mention that this is the read counterpart to update_metrics_history_retention_setting, nor does it clarify if it is specific to a host or global. An agent must infer from the name alone that this fetches a retention setting, but without context on when to call it or what it returns, usage guidance is effectively absent.

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