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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the write semantics and safety profile are covered without the description. The description adds caller context, but it does not say what record/state gets created, why the call is idempotent, or what the returned destination looks like — and with no output schema, that return detail matters.

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 short, front-loaded sentences with no filler, and the caller restriction comes first. The brevity, however, edges into cryptic phrasing that costs more clarity than it saves.

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 zero schema description coverage, the description must carry the return contract and parameter meaning — yet it never states that the response is an upload destination/URL or what content_type and size_bytes should contain. An agent could not call this correctly on the description alone.

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 both required parameters (content_type, size_bytes) are undocumented in the schema. The description offers no units, format, or expected values for them; only "the image the person dropped" weakly implies content type.

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 hints at the outcome ("answers where to send the image") and a caller restriction, but never states the actual action: creating an upload target/resource. An agent must infer the verb+resource from the name alone, which is vague rather than specific.

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?

"Only the VecSnap card calls this" is an explicit exclusion that tells an agent not to invoke it from a general chat/tooling flow. It stops short of naming what to use instead, but the when-not guidance is clear and front-loaded.

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