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

No annotations are supplied, so the description carries the burden: it discloses the return shape (slug plus how many of each kind are held) and an unusual cost signal ('One call costs one answer'), which tells the agent this call is metered. It stops short of stating read-only semantics or pagination/result-size behavior explicitly, leaving a small gap for an unannotated 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?

Front-loaded with purpose in the first clause, then alternatives, then the parameter, with zero filler and no repetition. The inline topic examples and em-dash list add length, though they do aid recognition of what a 'kind' is.

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 one-optional-parameter list tool with no output schema, the description supplies everything missing: what fields come back (slug, count), how filtering works, and which sibling to pick instead. Nothing an agent needs in order to call it correctly is absent.

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% and the single `q` parameter is already documented as 'Words the label must carry. Omit for every topic.' The description restates this ('q narrows the list to labels carrying those words; omit it for all of them') without adding matching syntax or behavior beyond the schema, so 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?

States a specific verb and resource ('List the kinds of recurring event the data is indexed by') and concretizes it with examples (CPI releases, FOMC statements, rate cuts, halvings). It also names what each item carries (slug and count), which makes the resource unmistakable against siblings.

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?

Explicitly routes the agent: use this to obtain the slug for get_topic_outcomes, use list_events for a single dated event, and use find_analogs or query_history for non-events. Both the when-to-use and the when-not-to-use cases are stated with named alternatives.

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