simulate_paymentSimulate test invoice payment outcomes—paid, partial, overpaid, or expired—to fire the same webhooks as real transactions for integration testing.
Test keys only: pretend the customer paid, paid part, overpaid, or let the invoice expire. Fires the same webhooks as real payments.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ||
| amount | No | For partial / overpaid | |
| outcome | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations, it discloses that the tool fires the same webhooks as real payments, which is an important side effect. It also clarifies the test-key restriction and the available simulated outcomes, adding meaningful behavioral 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?
Two compact sentences, front-loaded with the key test-mode constraint and followed by the webhook behavior. There is no wasted text.
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?
It covers the test-mode scope, outcomes, and webhook side effect well, and annotations already communicate the safety profile. The main remaining gap is that the required 'id' parameter is never explained, which could matter for correct invocation.
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 description maps the outcome choices into natural language, such as 'paid part' and 'let the invoice expire', which helps interpret the enum. However, with only 33% schema description coverage, it does not clarify the required 'id' parameter, so the parameter semantics remain partially incomplete.
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 states a specific action, simulating payment outcomes, and clearly frames it as test-mode invoice payment behavior. It distinguishes itself from real payment and from the invoice-management siblings through 'Test keys only' and the simulated outcomes.
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?
'Test keys only' gives a clear usage constraint and effectively excludes live-mode use. It does not explicitly name alternatives or when-not scenarios, but for this test-only tool the context is sufficiently clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.