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 | ||
| credits | No |
Changes observed during successful MCP inspections.
Output schema / additionalPropertiesRemoved value: -trueOutput schema / properties / credits / descriptionRemoved value: -"Remaining credit balance."Output schema / properties / status / descriptionRemoved value: -"Account status."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?
The annotations already establish read-only, idempotent, non-destructive behavior, so the safety profile is covered. The description does add genuine non-duplicative context: that secret-key auth can target either an end user or the pooled account. However, it does not explain what a missing key or a non-secret key does, which is the behavior an agent would most need.
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, verb-first, with no filler. It is arguably over-terse, but nothing wasteful is present.
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?
An output schema exists, so return values need no explanation, and annotations cover safety. Still, for a tool whose result depends on auth mode, the description leaves the auth requirement and the meaning of "credits" (unit, scope) unstated.
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% and the schema already documents external_user_id as an end-user id for secret-key auth. The description adds meaning the schema lacks: that omitting it can resolve to the pooled account, clarifying the optional parameter's semantics.
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?
"Get credits" names a verb and a resource, but the resource is stated as "credits" while the tool is get_balance, leaving the agent to infer that this returns a credit balance. It gives no differentiation from billing-adjacent siblings such as estimate_cost or cancel_cost_approval.
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 statement of when to call this versus another tool, and no prerequisites beyond an oblique mention of secret keys. The agent must infer that this is the tool for checking remaining credits rather than a cost-estimation path.
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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