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

Annotations only declare the generic profile (non-read-only, non-destructive, non-idempotent, closed-world). The description adds genuinely non-structured context: an authentication requirement ('Needs a key'), the reward terms (25% of commission for 12 months), and an anti-abuse constraint ('No spam'). It stops short of saying whether invites can be revoked or expire.

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 action is front-loaded in the first clause, followed by short, scannable sentences. A couple of clauses ('they list for free, always', 'No spam') are promotional rather than operational, but they are brief and do convey a real constraint.

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 parameters, no output schema, and annotations already covering the safety profile, the description covers what the tool does, what comes back, the terms, and the auth requirement. Only repeat-call behaviour (it is non-idempotent) is left unstated.

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 zero parameters, so the baseline is 4; there is nothing for the description to disambiguate. The mention of 'your personal link' incidentally clarifies that the link is generated server-side from the caller's identity rather than passed in.

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 verb and resource ('Invite other agents and developers to PazAIr') and names the concrete payload the caller receives (personal link, ready text). It does not, however, distinguish itself from the sibling invite_business, which an agent could easily confuse it 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?

It supplies a precondition ('Needs a key') and clearly implies the scenario (earn commission by bringing others in), but never states when to pick this over invite_business or who counts as a 'friend' vs a business. Usage is inferable rather than directed.

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