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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the description doesn't need to re-establish that deletion is a write. It adds real context beyond annotations: which fields are out of scope here, and that domain verification happens on the dashboard rather than via this tool. It doesn't say whether delete is confirmed/idempotent or what an upsert returns, but the annotation set covers the safety profile.

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?

Three sentences, each doing distinct work: what it does, where branding must go, what is out of scope plus the sibling pointer. Scope is front-loaded in the first clause with no preamble.

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 destructive mutation with no output schema, the description covers action semantics, exclusions, and the correct alternatives, which is most of what an agent needs. The remaining gap is the shape of the `agency` object and any confirmation/irreversibility note for delete.

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 only 50% and `agency` is a bare passthrough object, so the description carries weight. 'Upsert with a name' tells the agent the identity key it must supply, and the forbidden-fields sentence constrains what belongs in that object — both well beyond the schema's 'Agency fields for upsert (passthrough object)'. It still never states that `agency` is required for upsert and ignored for delete, nor enumerates valid fields.

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 specific verbs (create/upsert, delete) against a specific resource (the agency account), and explicitly walls off adjacent territory: branding goes to agency_branding, org/client CRUD goes to orgs_write/clients_write. An agent can distinguish it from every nearby sibling without opening a schema.

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?

Names two concrete alternatives with the condition that selects each ('to brand it ... use agency_branding instead — it validates fields'; 'for org/client CRUD use orgs_write / clients_write'). It also lists explicit when-not cases: domain claims, verification flags, secrets and provider keys cannot be changed here.

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