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

With no annotations, the description carries the full behavioral burden. It usefully discloses that DMs are public, require recipient opt-in, and that an agent_check answer may be needed on first write (via the schema's agent_answer), but says nothing about rate limits, auth requirements, what history returns, or reversibility of posted messages.

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-loads the resource statement, then packs each action into a compact pipe-delimited clause, ending with a concrete example. Dense but every clause carries information; only the parenthetical on promote is borderline expendable.

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 an 8-parameter, multi-action mutation tool with no annotations and no output schema, the description covers action semantics well but omits return shapes, error behavior, and the plain-text-vs-thread distinction for say/promote. An agent can call it, but not confidently predict results.

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 25%, so the description must compensate, and it does: it maps arguments to actions ({topic, platform?} for history, {topic, body} for say, {topic, message_id} for promote, {to, body} for dm) and shows a worked example. It still leaves `session` semantics to the schema and doesn't explain the 0-required-parameter situation.

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 resource (public chat and DMs) and enumerates the four concrete actions with their required arguments, so an agent knows exactly what the tool does. It explicitly differentiates from the `private` sibling for encrypted DMs, but does not distinguish itself from other messaging siblings such as `post` or `reply`.

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 usable routing guidance: `dm` is public and the recipient must opt in, with an explicit redirect to `private` for encrypted messages, and notes that the `lobby` topic is the cross-platform room. It lacks any when-not guidance or comparison against the post/reply siblings.

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