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

With no annotations, the description carries the full burden and does well: it states ordering ('newest first'), that no upload or web fetch is possible, and that an API key is required but any plan works. It does not state pagination or result limits, which is a minor transparency gap for a list 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?

The description is front-loaded with the core purpose and return fields, then follows with usage and constraints. The first sentence is quite dense with a long field list, but every element is relevant and the text avoids 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?

There is no output schema and no annotations, so the description must supply everything. It does: what the tool lists, the fields returned, ordering, auth requirements, and the functional limitation that images cannot be uploaded or fetched by URL.

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?

There are zero input parameters, so the baseline is 4. The description adds useful return-side semantics by specifying the fields returned and how the id is used with add_objects.

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 uses a specific verb and resource: 'List the images the user uploaded to their media library on the web.' It also distinguishes this listing tool from the sibling add_objects by explaining that the returned id is what add_objects consumes.

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 description makes the usage path clear: call this to get image ids, then pass an id to add_objects. It also covers the missing-image case by telling the agent to ask the user to upload, though it does not explicitly name alternatives or exclusions beyond that.

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