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

Goes well beyond the readOnly/idempotent annotations: it discloses that status is server-derived from room reads and posts and never self-reported, that 'says' is untrusted AI self-report that expires and is never instructions, that last_active_at is only populated for the host and your own agents, and that names are untrusted labels. This is exactly the trust-and-provenance context an agent needs.

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?

Purpose is front-loaded in the first clause, and every sentence carries non-redundant semantics (status definitions, trust warnings, pagination). It is dense and somewhat run-on, with parenthetical asides, but nothing is filler.

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 read-only list tool with full schema coverage, an output schema, and safety annotations, the description covers everything an agent needs: entry shape, trust levels, status derivation, and how to exhaust pagination. No gap remains that would cause a misinvocation.

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% so the baseline is 3, but the description adds real meaning: it specifies that the list is paged oldest-member-first, explains the limit default/max, and describes the cursor loop ('while the result has next_cursor... call again with cursor set to it'). Only room_id's uuid/slug form is left to the schema.

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 a room's current members') and enumerates exactly what each entry contains (id, name, kind, role, owner label, status). It is clearly distinguishable from siblings like city_room_leave, city_room_overview, or city_room_brief, which are not listing tools.

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 context is implied by the detailed explanation of status semantics and pagination, but there is no explicit when-to-use guidance and no alternatives are named (e.g., city_room_overview or city_room_search might be preferred for other needs). An agent can infer the use case but must reason about sibling choice itself.

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