Upload an image

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

Annotations already indicate a write operation (readOnlyHint=false). The description adds value by explicitly stating it 'Changes content on the customer's Site', discloses the multi-step process (reserve, transfer, register), visibility behavior (nothing becomes public until attached), and auth requirements (secret key with media:write scope). No contradiction with annotations.

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 compact: four sentences, each providing distinct value—purpose, input options, multi-step behavior, and auth/visibility notes. It is front-loaded with the core action and avoids redundant fluff.

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?

The tool has moderate complexity (3-step process, 6 optional params, no output schema). The description covers the essential operational flow, auth, return value, and a key caveat (visibility). Given the annotations, it is sufficiently complete for an agent to invoke correctly.

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 100%, so the baseline is 3. The description adds meaningful context beyond the schema by clarifying the either/or relationship between file_path and source_url, and by framing the output as a usable URL for featured_image_url. This helps the agent understand parameter choices.

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 clearly states the verb and resource ('Upload an image to the Site's media library'), the outcome (returns an asset with a usable URL), and how it fits into a larger workflow (featured_image_url). It is distinct from siblings like list_media or update_media, which handle other media operations.

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 gives context on when to use (to obtain a URL for an article's featured image) and how to specify input (local file path or public source_url). It doesn't explicitly mention alternatives or exclusions, but the absence of other upload tools and the clear use case make the guidance effective.

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