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

The annotations declare readOnlyHint=true, yet the description describes a write operation ('upload a file ... get a public link') that persists a new resource for up to 7 days. That directly conflicts with the read-only claim. The otherwise useful behavioral detail (1 MB cap, sandboxing, $0.01 x402 cost) does not offset the contradiction.

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?

Four compact sentences, front-loaded with the core capability before formats, safety and pricing. Every sentence carries information except 'Served safely sandboxed', which is close to filler. No wasted preamble.

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 and 5 parameters at 60% coverage, the description covers fairly well: formats, size limit, link lifetime, cost and sandboxing. It leaves the mutual exclusivity of the three input modes to inference and says nothing about replacing/expiring/retrieving hosted files, but nothing critical for a first correct call is missing beyond that.

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 coverage is only 60%, and the description compensates: '(text, base64 or copy from a URL)' reveals that the text, content_base64 and url parameters are three alternative input modes, which the schema itself does not state. It also adds a 1 MB size constraint not present in any parameter description, and '7 days' ties to the days parameter.

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?

States a specific verb+resource with real scope: 'File hosting: upload a file ... and get a public link that lasts up to 7 days.' An agent immediately knows this is a hosting/upload tool rather than a file reader or converter. It does not, however, differentiate itself from the sibling 'storage' tool, which is the closest ambiguous neighbor.

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 value proposition (a public link, up to 7 days) implies when to reach for it, but there is no explicit when-to-use, when-not-to-use, or alternative routing against siblings like storage or link_short. Usage is inferred from the description rather than stated.

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