GetV1InstancesPayinsByIdRetrieve a specific payin from a BlindPay instance using its instance ID and payin ID to inspect payment details and status.
Retrieve Payin
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ||
| instance_id | Yes |
Changes observed during successful MCP inspections.
v1.9.3Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so safety behavior is covered. The description adds no additional behavioral context such as error behavior, what a missing payin returns, or any constraints beyond the annotations.
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 extremely short, but it is under-specified rather than appropriately concise. It is front-loaded with a verb and resource but omits essential context needed to select and invoke the tool correctly.
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 tool with two required undocumented parameters, no output schema, and no parameter descriptions, the description does not provide enough information to call the tool confidently. It gives no detail about the ID format, instance scoping, or return value beyond what annotations imply.
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%, so both required parameters are undocumented, and the description does not explain what 'id' versus 'instance_id' means. The two-word description provides no parameter meaning at all, leaving the agent with only parameter names and examples.
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 says 'Retrieve Payin', which identifies a read operation on a payin resource, but it does not mention lookup by ID or the instance scope. It is vague enough that an agent cannot distinguish it from sibling list tools like GetV1InstancesPayins without inspecting the name or schema.
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?
There is no guidance about when to use this tool versus GetV1InstancesPayins or other payin-related tools. The agent must infer that this is a single-resource lookup by ID from the tool name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.