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

Discloses behavior the annotations cannot express: the panel is interactive and requires the user to click a tile, and the click attaches the selection to the given draft (consistent with readOnlyHint=false, destructiveHint=false). It also preempts a likely misconception by stating 'Nothing is uploaded.' It stops short of describing failure modes, whether the draft is modified immediately, or what happens if the user cancels the panel.

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, front-loaded with the action and mechanism, then the use/avoid clause. Every clause earns its place; no restatement of the name or title.

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 single-parameter, no-output-schema tool, the description covers the action, the interaction model, the side effect (attach to draft), and the sibling boundary. The only gap is what an agent observes after the user picks or dismisses the panel, which is minor.

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?

Only one parameter, and the schema description coverage is 100% with a detailed draft_id entry (full UUID, never abbreviate). The description's 'the given draft' adds no syntax beyond the schema, so baseline 3 is appropriate.

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 concrete action (open an interactive thumbnail-grid panel of library media) and the resource (images, videos, GIFs, PDFs already in the library). It also distinguishes itself from attach_media_from_url and upload_media by contrast, so an agent can route correctly without opening sibling schemas.

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?

Explicit when-to-use ('reuse an asset they added earlier') and explicit when-not ('NOT for a file sitting on their machine'), naming the correct alternative tool (upload_media). Nothing is left to inference.

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