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

With no annotations provided, the description carries the burden and does meaningful work: it discloses that no auth or arguments are required (safe to call blind) and that create_inbox is free/no-key. It stops short of stating idempotency, rate limits, or that it is strictly read-only, but 'Show' implies non-mutation.

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 with zero filler: content scope is front-loaded, then preconditions and the next action. Every clause 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?

No output schema exists, and the description compensates by enumerating the returned content (credit costs, free tier limits, enabled crypto rails). For a zero-param, no-annotation informational tool, an agent has everything needed to call it and use the result.

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?

Zero parameters, so the baseline is 4. The description reinforces the empty schema with 'No arguments', leaving no mismatch for the agent to reconcile.

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?

Uses a specific verb (Show) with an enumerated set of resources: inbox credit cost, free tier limits, and enabled crypto payment rails. An agent can tell this is the informational/pricing lookup and distinguish it from the sibling action tools like create_inbox or send_message without opening a 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?

States preconditions explicitly ('No arguments, no auth') and gives the follow-up step ('Next: call create_inbox (free, no key) to start'), which orients the agent in a workflow. It doesn't name a case where this tool should be avoided, but for a zero-argument read tool there is little ambiguity to resolve.

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