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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds meaningful behavioral context beyond the annotations: it discloses the returned fields (status, dimensions, DPI, preview URLs) and implies asynchronous processing by instructing the agent to poll after file creation. It does not cover auth nuances, rate limits, or error behavior, which keeps it from a 5.

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 sentences are tightly packed and front-loaded: the purpose comes first, followed by the returned fields, the polling guidance, and the API endpoint. Every clause contributes information, and there is no redundancy or filler.

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 no output schema, the description carries responsibility for explaining return values, which it does by listing the key fields and status values. It also frames the tool within a polling workflow after printful_add_file. Minor gaps remain around error handling and response structure, but for a simple two-parameter GET, the agent has enough to invoke it correctly.

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 both file_id and store_id are fully documented in the schema itself. The description adds no further syntax, format, or usage detail for either parameter. Baseline 3 is appropriate when the schema does all the parameter work.

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 one File Library entry.' It clearly distinguishes this read operation from its write counterpart by naming printful_add_file as the preceding step, and it enumerates the returned data (processing status, dimensions, DPI, preview URLs), leaving no ambiguity about what the tool does.

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 gives explicit timing guidance: 'Poll this after printful_add_file.' This tells the agent exactly when to call it in a workflow. It stops short of stating when not to use it or naming alternative file-listing tools, but the context is clear and actionable.

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