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

Annotations already cover readOnly, idempotent, and non-destructive behavior, so the bar is lower. The description adds real domain context beyond them: results are count-ranked, each subject links to an authority page, and subjects absorbed the former tag facet. It omits pagination/limit behavior, which is left to the 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?

Three tight sentences, front-loaded with what it lists and how results are ranked. The tag-facet sentence earns its place as disambiguation; the closing authority-page clause is slightly dense but not wasteful.

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, the description does the work of describing the return: ranked subject headings with per-item counts implicit in the ranking and an authority page per subject. Pagination via offset is unaddressed, a minor gap for a 3-parameter read-only 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?

Three parameters at 67% schema coverage: `limit` (default 50, max 300) and `keyword` (substring filter on the heading) are documented in the schema, while `offset` has no description anywhere. The description adds no parameter syntax or filtering detail, so it performs at the baseline rather than compensating for the offset 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?

States a specific verb and resource (list subject headings) plus the ordering rule (ranked by item count) and the return shape (each subject's own authority page). It is clearly distinguishable from siblings like list_categories, list_years, and list_journals, which cover different facets.

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 downstream: feed a value into the `subject` filter of search_research_items to retrieve items, and clarifies that free-form tags no longer exist as a separate facet. It does not state when to prefer this over browsing the similarly-named list_categories/list_years, so it stops short of full when/when-not guidance.

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