List the measured metrics

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

Annotations already declare readOnly, idempotent, and non-destructive behavior, so the safety profile is covered. The description adds valuable context by enumerating the returned fields and explaining what comparable_since means, which compensates for the absent output schema.

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 field list is front-loaded and the usage hint follows compactly in a second sentence. The long enumeration is dense but each item earns its place by documenting a return field; no filler text.

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?

With no output schema and only one optional parameter, the description is the only source for return-value information and it supplies the key fields. Ordering, pagination, and result limits are not mentioned, which is a minor gap for a listing tool.

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 coverage is 100%, so the baseline is 3, but the description adds beyond the schema by noting that filtering also surfaces notes and clarifying that filter accepts a key fragment, a definition id, or a note word. That is genuine semantic value over the structured field.

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 resource (every metric the ledger measures or archives) and enumerates the returned fields, so an agent knows this is the metric catalog tool. It does not explicitly differentiate itself from close siblings like metric_history, which weakens it slightly.

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 concrete usage hint: apply a filter to also receive notes. There is no guidance on when to use this versus metric_history or the other ledger tools, and no exclusions, so usage is implied rather than specified.

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