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

Annotations already declare readOnlyHint=false, idempotentHint=false, openWorldHint=false, so the agent knows this is a non-idempotent write with no external side effects. The description usefully adds that the returned viewUrl is stable and intended to be shared in chat, but omits auth/permission requirements and any size or rate constraints for an upload operation.

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?

Three short, front-loaded sentences; the core action and return value lead, with parameter hints after. Efficient, though the CLI-flag phrasing is a small source of noise given the actual schema parameter names.

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 file-upload tool with no output schema, the description covers the action, the main input, and the key return field (viewUrl). It leaves out the authentication context that the schema implies (projectApiKey required on every call) and gives no limits or failure behavior, leaving gaps an agent may need.

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 only 40% (botId and projectApiKey are the only documented properties), so the description should compensate more than it does. It names the required file plus the optional filename and content-type, but uses CLI-style flags ('--file', '--content-type') while the schema uses 'file' and 'contentType', and it never mentions botId or projectApiKey.

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 and resource (upload a file to explore-snaps) plus the outcome (returns a stable view URL), which is a distinguishing capability no sibling tool provides. An agent can tell immediately what this does without opening the 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?

The parenthetical '(e.g. agent screenshot evidence)' implies a usage context, and the response note about pasting viewUrl in chat hints at downstream intent. However, there is no explicit when-to-use/when-not guidance and no alternatives named, so context is implied rather than stated.

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