apply_credit

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

The description adds a critical behavioral disclosure—'списывает средства со счёта' (debits funds from the account)—which goes beyond the annotations (readOnlyHint=false, openWorldHint=true). It also clarifies that partial or full payment is possible. However, it does not mention irreversibility or refunds, though destructiveHint=false suggests no destructive deletion. The added context is valuable.

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 description is two short sentences, front-loading the main action and then adding the financial impact. Every word serves a purpose, with no redundancy or filler. It is concise and well-structured for quick comprehension.

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 financial operation, the description covers the core behavior (payment from credit) and the money debiting, which are the most important contextual elements. It does not mention return values or failure modes, but given the simplicity of the operation and the schema covering all parameters, the description is sufficiently complete for an agent to call it correctly.

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 coverage is 100%, meaning all three parameters have descriptions in the schema. The description does not add extra meaning to any parameter; it only repeats the general purpose. Since the schema already documents the confirm, amount, and invoice_id fields, the description adds no additional parameter-specific insight.

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 clearly states the action (pay an invoice) and the source (credit balance), using a specific verb and resource. It distinguishes itself from siblings like get_invoice, mass_pay, and create_addfunds_invoice by focusing on applying credit. The mention of 'полностью или частично' adds nuance, making the tool's scope unambiguous.

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 description implies the use case (paying an invoice from credit balance) but does not explicitly contrast it with alternative payment tools or state when not to use it. There is no mention of alternatives or exclusions, so the agent must infer the appropriate context from the description alone.

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