get_balanceGet credits. Secret keys may select an end user or the pooled account.
| Name | Required | Description | Default |
|---|---|---|---|
| external_user_id | No | End-user id; secret-key auth only. |
| Name | Required | Description | Default |
|---|---|---|---|
| status | No | Account status. | |
| credits | No | Remaining credit balance. |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "additionalProperties": true,
+ "properties": {
+ "credits": {
+ "description": "Remaining credit balance.",
+ "type": "string"
+ },
+ "status": {
+ "description": "Account status.",
+ "type": "string"
+ }
+ },
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful context about the pooled account vs end-user selection, which is beyond the schema. However, it doesn't detail response structure or potential errors, which could be important.
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 short sentences, focused and efficient. The key information (credits and auth-dependent account) is front-loaded. Minor ambiguity in 'credits' vs 'balance' but acceptable.
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?
Given the simplicity of the tool (one optional param, no nested objects, has output schema), the description is nearly complete. It explains the auth nuance, and the output schema likely covers return values. It doesn't mention potential error cases or rate limits, but those are not critical here.
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 100%, and the parameter description is self-explanatory. The tool description does not add significant extra semantics beyond the schema, but this is acceptable because the schema already covers it.
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 tool's purpose: getting credits/balance. It mentions the optional external_user_id for secret-key auth, which adds specificity. However, it doesn't explicitly differentiate from sibling tools like estimate_cost or describe_api, but the verb+resource is clear enough.
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 usage: it says secret keys may select an end user or pooled account, hinting at auth context. It does not explicitly state when to use this vs alternatives, but given the simple purpose, that is acceptable. The parameter description in the schema further clarifies the usage condition.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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