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

Annotations already indicate readOnly and idempotent, and the description adds the key behavioral context that the result depends on the user's OAuth grant(s), that filtering by platform is supported, and that each entry contains specific fields. It does not discuss pagination or rate limits, but the OAuth-scope disclosure is genuinely useful beyond annotations.

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: purpose, use case, filtering behavior and return fields. Each sentence adds information, there is no fluff, and the core action is front-loaded.

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 simple, read-only list operation with one optional parameter and no output schema, the description covers the OAuth context, filtering behavior, default value, and the fields received. Nothing an agent needs to invoke it correctly is missing.

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 only parameter, platform, is already fully documented in the schema with its enum values ('google', 'bing', 'all') and default. The description repeats this information without adding new syntax or edge-case detail, so per the 100% schema coverage baseline it adds no extra semantic value.

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 opens with a specific verb-resource pair: 'Return advertising accounts reachable from the user's OAuth grant(s)'. It names the platforms (Google Ads, Microsoft Advertising via 'google'/'bing'), the intended use case, and the returned fields, making it immediately distinguishable from sibling list/set/get tools like list_brands, set_brand_ad_account, and get_account_summary.

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 clear context: 'useful for agency managers and account owners who need to pick which account a brand publishes into.' This tells an agent when to call it, though it does not explicitly state exclusions or name alternatives such as get_account_summary or set_brand_ad_account.

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