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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true, openWorldHint=true). The description adds genuinely new behavioral context: the tool produces a hosted link and never moves money automatically, which is the key thing an agent must know before invoking a payment-adjacent tool.

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 tightly-packed sentence with the precondition front-loaded and zero filler. The phrase 'hosted funding link' is left unexpanded, slightly costing clarity for terseness.

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 write tool with no output schema and no parameter documentation, the description covers the safety-critical guardrails but not what the caller gets back (a URL? an id?) or how the idempotency key behaves. Adequate for a cautious agent, incomplete for an agent that needs the return value.

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 0% and the description explains none of the three required parameters. The schema does carry constraints (currency const USD, amount range 1–100000000, key length 8–150), but the meaning of amount_minor as minor units and the role of idempotency_key are left entirely to inference.

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 ('create a hosted funding link'), and clarifies the effect is a link rather than a charge. It does not differentiate itself from the lookalike sibling create_payment_link, 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?

Gives an explicit gating condition ('Only when the owner asks') and an explicit exclusion ('never automatically charge a card or top up after insufficient funds'). It stops short of naming alternatives such as create_payment_link or send_with_credits, so the agent must infer the routing itself.

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