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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds two non-obvious behavioral facts beyond the schema: a hard cap of 'Up to 50' results per call (implied pagination limit) and a cost of '1 credit' per invocation, which is genuinely useful operational context.

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 terse fragments, front-loaded with the core purpose, then the id source, limit, and cost. Almost no waste, though the fragments are somewhat telegraphic and the id-parenthetical interrupts the main clause.

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 exists, yet the description does not describe the return shape (e.g., a list of user objects), only the cap and cost. With low schema coverage and no output schema, an agent gets enough to invoke but not enough to interpret the response fully.

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 only 33% (only user_id is documented), so the description must compensate. It adds the natural-language meaning of direction ('followers or the accounts it follows'), and echoes the count cap of 50, but leaves count's semantics and the exact followers/following enum mapping only partially clarified.

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 and dual operation ('followers or the accounts it follows') for a TikTok account keyed by numeric user_id. It partially distinguishes itself by pointing at tiktokUser as the source of the id, though it doesn't contrast sharply with siblings like instagramFollowers or tiktokUser.

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?

Usage is implied rather than stated: the description notes the id comes from tiktokUser (data.user.id), which tells the agent a prerequisite step. It never says when to choose this over alternatives or when direction=followers vs following applies.

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