liveauth_mcp_charge

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

With no annotations provided, the description must disclose behavioral traits on its own. It mentions the action 'Meter API usage' but does not explain side effects like deducting sats, idempotency (e.g., calling twice), prerequisites beyond JWT authentication, or error behavior. As a monetary/charge operation, the lack of these details is a significant gap.

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 concise—two short sentences that front-load the core action ('Meter API usage') and then provide the invocation details. There is no redundant or filler content; every sentence earns its place.

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 optional parameters, the description gives a decent overview of purpose and usage. However, with no annotations or output schema, it omits important context such as the expected response, idempotency, and failure modes. It is minimally sufficient but not fully complete for a financial metering operation.

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 input schema already provides full documentation for both parameters (100% coverage). The description adds minor context (e.g., 'cost in sats for each API request') but does not meaningfully enrich the understanding of toolName or callCostSats beyond their schema descriptions. The high schema coverage justifies the baseline score of 3.

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 function: 'Meter API usage after making an authenticated call.' It identifies a specific verb (meter/charge) and resource (API usage), and the context (after an authenticated call) distinguishes it from sibling tools like liveauth_mcp_usage, which likely queries usage rather than recording it.

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 explicitly instructs when to call the tool: 'Call this with the cost in sats for each API request made using the JWT.' This clearly conveys per-request usage after authentication. However, it doesn't explicitly mention alternatives or conditions when not to use it, preventing a perfect score.

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