get_esim_qr

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

With no annotations, the description carries the full burden. It discloses that the return is an image and that clients may render it inline, which is useful behavioral detail. However, it does not mention potential error states (e.g., invalid eSIM ID), whether the QR is a one-time activation code, or any permission or state requirements.

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 two sentences long, front-loaded with the core purpose, and contains no filler. Every clause adds value: it states the action, the resource, the output type, and a practical rendering detail.

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 simple one-parameter tool with no output schema, the description covers the essential aspects: what it does, what it returns, and how the result is typically presented. Missing details like error handling are less critical here, but the description could still mention the nature of the eSIM ID for full clarity.

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 0%, and the description does not explain what esim_id refers to or how the agent should obtain it. The parameter name is somewhat self-explanatory, but the description adds no guidance beyond the schema, failing to compensate for the lack of schema descriptions.

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 starts with a specific verb ('Fetch') and resource ('activation QR code for an eSIM'), clearly distinguishing it from sibling tools like get_esim_status or topup_esim. It also states the output format ('as an image'), making its function unambiguous.

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 second sentence explains that most MCP clients render the image inline for direct scanning, which implies the tool is intended for obtaining a scannable QR code. It gives context on the output behavior but does not explicitly mention when to prefer this over alternatives or any prerequisites such as having an eSIM ID from a prior purchase.

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