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

Adds substantial context beyond the annotations (destructive, idempotent, openWorld): it validates the customerId against the user's accessible-accounts list, prevents hallucinated-ID redirect, and discloses that live campaigns in the old account are untouched while future drafts retarget. Slightly incomplete on auth requirements and whether the old binding is retained.

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 tight paragraphs with zero filler, front-loading the core action and the validation rationale before the when-to-use conditions. Every sentence earns its place.

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, but annotations already convey safety profile and the description covers purpose, triggers, validation, and side effects. The one gap is that it doesn't state the return/confirmation an agent should expect or permissions needed, though these are minor for a 2-param mutation.

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 50% — customerId is documented in the schema with a list_ad_accounts pointer, but brandId is undocumented. The description reinforces the customerId validation semantics (must be accessible/valid) but adds no syntax or constraint detail for brandId, so it only marginally exceeds the schema.

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?

Specific verb (change/rebind) plus precise resource (brand's Google Ads customerId publish target). It cleanly distinguishes itself from siblings like create_brand and set_master_account by naming the exact binding it mutates.

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?

Explicitly enumerates two triggering scenarios: (a) brand bound to wrong account at creation, (b) agency moving a client between MCCs. It also clarifies the scope of effect, so an agent knows when this is the right call versus creating or editing a draft.

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