list_metrics

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

With no annotations, the description must carry the full behavioral burden. It does disclose the shape of the result (id, label, unit, kind, lens, latest value) and the case-insensitive substring matching rule, plus the tier values, but says nothing about result volume, pagination, unknown-ticker behavior, or that the call is a non-mutating read.

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?

Compact and front-loaded: the return payload is stated first, then the two optional filters in order of appearance in the schema. The opening fragment 'The series a ticker has' is slightly clipped and the field list mixes names without explanation, but no sentence is wasted.

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?

There is no output schema, no annotations, and no parameter descriptions in the schema, so the description is the only source of information. It adequately covers return fields and the two filters but leaves ambiguous fields like 'lens' and 'kind' undefined and says nothing about limits, ordering, or failure modes.

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 `tier` has no enum, so the description does real work: it defines `search` as case-insensitive substring matching on ids or labels and constrains `tier` to 'curated' or 'xbrl' with the condition under which it matters. Only `ticker` is left unexplained, though it is self-evident.

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 names the resource precisely ('The series a ticker has') and enumerates the returned fields, so an agent understands this lists the metric/series inventory for a ticker. The verb 'list' is only implicit and there is no differentiation from siblings such as get_series, which retrieves a single series.

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?

Usage is implied through the parameter explanations: use `search` to narrow by id/label substring and `tier` to disambiguate when a ticker exists in both curated and xbrl. However, there is no statement of when to call this versus get_series or list_companies, and no prerequisites or exclusions.

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