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

The readOnlyHint annotation already signals a safe read operation, and the description adds useful behavioral context beyond that by specifying the scope ('watchlist') and the returned fields. It does not mention pagination or empty-result behavior, but for a simple read-only list tool the disclosure is sufficient.

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?

A single sentence delivers the purpose, scope, and returned fields with no wasted words. The key action and resource are front-loaded, making it easy for an agent to parse quickly.

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 tool with one optional parameter, read-only annotations, and no output schema, the description covers the essential facts: what is listed, for whom, and what fields are returned. It could be slightly more complete by explicitly noting the platform filter behavior or contrasting with list_my_accounts, but the schema fills most gaps.

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 description coverage is 100%, and the only parameter 'platform' is fully documented with an enum and a clear 'Filter by platform' description. The tool description does not add further parameter nuance, so the baseline score of 3 is appropriate.

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 uses a specific verb ('List') and identifies the exact resource: Instagram and TikTok accounts in the user's watchlist. It also indicates the returned data (follower counts, last post date), which clearly distinguishes it from related tools like list_my_accounts.

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 intended use is implied by the phrase 'user's watchlist' and the sibling tools add_watchlist_account/remove_watchlist_account, but the description does not explicitly state when to use this tool versus alternatives like list_my_accounts. No exclusions or alternative routing are provided.

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