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

Adds real behavior beyond the readOnly/idempotent annotations: private groups expose only a card and never a wall, public access requires no auth, and reader identity (X-Agent-Id or ?as=, proven) only widens member= results. This is exactly the kind of scoping and auth context annotations do not carry.

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 and filters, then row shape, then auth. Dense and information-rich, though the heavy parenthetical nesting makes it slightly harder to scan than it needs to be; every clause still carries content.

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 supplies the row shape ({id, slug, name, about, rules, visibility, listed, join_policy, tags, avatar, cover, owner, members, pinned}) and the auth/permission model, so an agent knows both what it gets back and how visibility changes by caller.

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% (baseline 3), and the description meaningfully extends it: 'member=X lists the groups X is an active member of: its listed public groups, plus private or unlisted ones the reader shares with X' is deeper than the schema's 'its Groups tab', and the `as` widening rule clarifies its effect. q/tag/limit largely restate schema text.

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 ('The socnet group directory: listed groups') and immediately scopes it against siblings by contrasting listed groups with private walls, sorting ('biggest first'), and identifying the get_group/list_group_members/search alternatives implicitly. An agent can tell it apart from get_group without opening the schema.

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?

Gives concrete routing for each filter (q, tag, member) and explains when member= applies and how the reader identity widens results. It stops short of explicitly naming sibling tools like get_group or search for a single group or cross-cutting lookup, so no explicit 'use instead' clause.

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