Roo — get shortlink QR image

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

With no annotations, the description carries the full disclosure burden and delivers it: default behavior returns an MCP image content block, save_to makes it write bytes to a file, the return value changes, and the failure mode (qr_not_enabled) is named. This is well beyond minimal transparency for a simple read tool.

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 efficient sentences: what is fetched, the prerequisite and error, and the default vs. file option. The core mechanism is front-loaded and 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?

With only two simple scalar parameters and no output schema, the description explains prerequisites, error behavior, default result, alternative result, and the save_to path rule. An agent has enough information to invoke it correctly and interpret the response.

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 100%, so the schema already documents id and save_to in detail. The description aligns with the schema but adds no new parameter-level semantics beyond the structured field 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 states a specific verb and resource: 'Fetch the QR image for a shortlink.' It also clarifies the role relative to the prerequisite sibling tool roo_set_qr_addon, so an agent can immediately understand what this tool gets versus what that tool configures.

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?

It is clear when the tool is usable: the shortlink must already have the qrCode add-on configured, and otherwise a qr_not_enabled error is returned. It does not explicitly list alternatives or exclusion cases, but it does reference the condition that decides usefulness through roo_set_qr_addon.

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