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

Annotations already declare readOnly, idempotent and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context the annotations cannot: that partial brand information already reaches the agent via instructions, so the tool's marginal value is the full kit plus example posts.

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, contents first then triggers, with no filler. The middle parenthetical about instructions in-app and over MCP is slightly clunky but earns its place by preventing redundant calls.

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 carries the burden of describing the return value and does so by naming the four sections. Slightly more detail on the shape (e.g. whether example posts are returned verbatim) would make it fully self-sufficient.

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?

Zero parameters, so the baseline of 4 applies; there is nothing for the description to disambiguate. No misleading parameter claims are made.

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 enumerates the resource contents precisely: voice, audience, rules and example posts, which lets an agent know exactly what they get back. It is clearly distinct from update_brand_kit, though the verb itself is only implied by the parenthetical 'call this' rather than stated up front.

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 three explicit triggers (user asks what is set, about to change something, need example posts) and an explicit exclusion: instructions already carry the voice and rules, so this call is only for the full kit. That is a both-directions routing rule rather than a generic 'use when needed'.

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