charge_now

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It only states that it queues a charge and is a write operation, but does not mention side effects (e.g., charging the card, potential failures), idempotency, rate limits, or authentication requirements. The reference to '202' is a hint but not a substitute for explicit behavioral transparency.

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 a single, concise sentence that front-loads the core action and scope. It avoids unnecessary fluff and efficiently communicates the essence. However, it lacks any structural segmentation (e.g., separate usage notes) that might otherwise enhance readability, but this is not a major flaw given the brevity.

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?

This is a mutating tool with a side effect (charging a card), and it has no output schema and no annotations. The description is drastically incomplete: it does not mention what response the agent will receive, what errors can occur (e.g., card declined, subscription invalid), whether the operation is asynchronous, or any preconditions. An agent cannot safely invoke it without significant guesswork.

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?

With 0% schema description coverage, the description was expected to elaborate on the parameter. It only refers to 'subscription' contextually but does not explain what subscription_id is, its format, or any constraints. The agent has to infer that this is likely a subscription identifier from the name and the description's mention of 'assinatura', but no additional meaning is provided.

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 ('queue an immediate charge') on a specific resource ('the saved card of the subscription') and explicitly notes the write scope. It is distinguishable from sibling read tools and other mutations, though it does not name alternatives. The mention of HTTP 202 adds a subtle hint about the response behavior.

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 on when to use this tool versus alternatives, no prerequisites, and no conditions that would trigger its use. An agent cannot determine from the description whether it is appropriate for a given scenario, such as whether the subscription must be active or whether a pending charge already exists.

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