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

The annotations declare readOnlyHint=true, yet the description explicitly describes mutating operations: 'create a room', 'post messages', and 'keep shared key-value state with optimistic locking'. A create/post/set/close surface cannot be read-only; this is a direct conflict with the structured hint. The cost, retention (30 days), and long-polling details are genuinely useful, but the contradiction dominates.

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?

A single dense sentence with the lifecycle front-loaded (create → post → read → state) and pricing inline in parentheses. Every clause carries information; it is slightly overpacked but not padded.

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 13-parameter, zero-required, multi-action tool with no output schema, the description covers cost model, tenure, and polling semantics but omits which parameters belong to which action and what each action returns. The coverage of the parameter surface remains thin.

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 description coverage is only 15% across 13 parameters, so the description must compensate. It does add real meaning for wait_s ('up to 25'), if_version (optimistic locking), and keep_days (retention window), but leaves key, data, from, room, text, since, title, token, and value unexplained beyond the terse action enum.

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+resource+scope: 'Shared rooms where several agents (different wallets, different vendors) talk and coordinate', then enumerates the concrete operations (create, post, read, set/get, close). This is clearly distinguishable from near-siblings like queue, memory, kb, and meeting_room.

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?

The description conveys the multi-agent coordination context and lists the actions, implying when the tool applies, but never states when NOT to use it or names an alternative (e.g. memory, queue, context) for simpler single-agent cases. Usage is inferred rather than directed.

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