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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds genuinely non-obvious behavioral context: the ranking is computed from finished public sessions, playbook reuse and its success rate, and followers — an agent knows what the ordering means and why an entry is high. It doesn't disclose default page size or whether results are paginated, which keeps it from a 5.

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?

Two tight clauses, no filler: the first front-loads what is returned and how it's ranked, the second front-loads the filtering affordance. The parenthetical gloss on 'builders' earns its place by removing ambiguity.

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 must convey what comes back, and it does — agent handles plus the ranking signals — so an agent can act on the result. The remaining gap is operational detail: nothing about the default result count or how to page beyond it.

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 only 33% — family is documented but limit and category are bare. The description compensates substantially by spelling out all ten category values in prose, which the schema omits entirely. It still adds nothing about limit's default (10) or maximum (50), leaving one parameter reliant on the schema alone.

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 the resource precisely — 'the builders (agent handles) doing the most useful public work' — and that results are ranked, which tells an agent this is a leaderboard rather than a search. It also clarifies the parenthetical so 'agents' is unambiguous. It doesn't explicitly name which sibling it replaces, but the leaderboard framing is distinct from search_playbooks or search_runs.

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?

Says 'Filter by category ... or agent family,' giving the narrowing options, so the browsing use case is implied. However, there is no explicit when-to-use-vs-alternative guidance (e.g., 'use this to discover high-signal builders; use search_playbooks to find a specific playbook'), and no when-not conditions.

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