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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description does add that the scope is the Echoly workspace and that the response carries time zone, current local time, plan and this month's usage — a non-obvious composite payload. With no output schema, though, it could say more about return shape or size, so the added value is moderate.

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 sentences, front-loaded with the resource and its contents, followed by the imperative usage rule. The loose parenthetical '(X, Telegram, …)' and the slightly drifting tail ('this month's usage') are minor slack, but every clause carries information in the absence of an output schema.

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?

No output schema exists, so the description must carry the response contents, and it does so in useful detail for the brands, accounts, time zone and usage fields. What remains unstated — response size, whether usage is per-brand or workspace-total — is minor for a zero-parameter read tool.

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?

There are zero parameters, so there is no parameter semantics to explain; the baseline for a no-parameter tool is 4. The description correctly adds no redundant argument talk and instead spends its space on the response contents.

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?

The description names a specific resource (brands in the Echoly workspace) and enumerates exactly what accompanies each brand: connected accounts on X/Telegram and approval mode. The verb is implicit from the name 'list_brands' rather than stated, and the enumeration of workspace metadata is clear enough that an agent can distinguish it from list_posts or get_post.

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?

It gives an explicit, actionable directive: 'Call this before create_post.' That is a concrete when-to-use condition tied to a named sibling. Missing is any statement of when not to call it, or of alternatives if only a cheap subset of the data is needed, so it stops short of a 5.

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