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

Annotations already declare readOnly/idempotent/closed-world, so the bar is lower, and the description still adds real context: this is a static vocabulary rather than account data, and guessing values yields validation errors. The misspelled `campaginLimits` example is a concrete, non-obvious behavioral warning. It stops short of describing response shape or size beyond the topic-narrowing hint.

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 front-loaded sentences: what it is, why it must be read, then what it is not. The spelling example and the sibling routing list both earn their place. Slightly dense, but no filler.

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 still conveys what comes back conceptually (which values exist, never account state) and warns about the failure mode of guessing. Adequate for a one-optional-param read-only lookup; only the response shape/size is left implicit.

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?

The single `topic` parameter has 100% schema coverage with an enum and its own description ('narrow the reference to one area to keep the response small'), so the schema carries the load. The tool description never mentions `topic` or suggests which value to pick for which task, so it adds nothing beyond the schema — baseline 3.

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 (the API's static enum/field vocabulary) and what it contains: enum values, step-field requirements, defaults. It also explicitly distinguishes itself from the four account-data siblings it could be confused with.

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 an explicit trigger ('read this before authoring a campaign flow or filtering by status') and an explicit alternative routing rule ('for the account's own tags, templates, personas or placeholders use tag_list/template_list/persona_list/placeholder_list'). Both when-to-use and when-not-to-use are covered.

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