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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It only mentions a 'max 50' limit and that it is 'Free', but does not disclose side effects, permissions requirements, idempotency, or error handling. For a mutation tool, this is insufficient.

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?

The description is extremely concise and front-loaded, stating the action and object immediately. The parenthetical adds useful constraint info, though 'Free' is somewhat incidental and could be removed without loss.

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?

Given the tool's simplicity (2 params, no output schema, no nested objects), the description covers the core purpose and a limit, but lacks behavioral details such as what happens on error or whether existing folder memberships are affected. It is adequate but not fully complete.

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 schema already provides 100% coverage with clear descriptions (folder_id as Folder UUID, account_ids as Account UUIDs). The description adds a potentially useful constraint ('max 50') that is not captured in the schema, giving it value beyond the baseline.

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 states the specific action ('Add'), the object ('accounts'), and the destination ('folder'), which clearly distinguishes it from the sibling tool 'add_videos_to_folder'. The 'max 50' limit adds further specificity.

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?

The description implies the use case (adding accounts to a folder) but provides no explicit guidance on when to use this tool versus alternatives like create_folder or remove_account. No exclusions or prerequisites are mentioned.

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