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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: a call is free (consumes no credits) and the returned values include today's free allowances and this key's daily credit limit, which is the kind of quota context annotations cannot express.

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?

Compact and dense — a single enumerative sentence plus two short fragments with no filler. The one weakness is that the most actionable guidance ("Free. Check it before a large paid step.") is trailing rather than 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?

With no output schema, the description carries the burden of describing return values, and it enumerates the returned fields (plan, credits, daily allowances, limits, collections) well enough for an agent to know what it will get. It does not cover error states or auth requirements, which is a minor gap for a read-only, free call.

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 tool takes no parameters, so there is no parameter semantics to explain; the baseline for a zero-parameter tool is 4. The description instead spends its words on what the call returns, which is the relevant substitute here.

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 user's Kolect plan, credits, limits, collections) and the verb is implied by the retrieval framing. It is clearly distinguishable from action siblings like save_creators or check_fake_followers, though it never explicitly names a sibling it contrasts 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?

"Check it before a large paid step" gives an explicit when-to-use condition, and "Free" signals the cost tradeoff that motivates that guidance. It stops short of naming alternatives or when-not-to-call, so it is strong context rather than full routing.

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