Add media from a URL

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

Goes well beyond the annotations: discloses safe-URL checking on every redirect, 3-redirect cap, 20s timeout, 20 MB limit with the filter name ab_mcp_upload_max_bytes, allowed MIME set, that each call adds a new file, and that the result becomes public. Also states required capabilities (upload_files, edit right on post_id) and the return shape.

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?

Front-loaded with the action, then behavior, then requirements, then return value, and every clause carries information (limits, MIME set, permissions). It is dense and runs as one long sentence chain, which slightly hurts scannability, but no sentence is redundant.

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, the description supplies the return object {uploaded, id, url}; with a mutation tool it supplies failure modes, limits, and permission prerequisites. An agent has everything needed to invoke and predict outcomes.

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 real meaning by tying post_id to an edit-permission requirement and constraining url to public http(s) that the site fetches itself. It adds little on alt/title beyond the schema, so not a 5.

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 + resource ('download a file from a public http(s) URL and add it to the media library') and explicitly differentiates from the sibling wp_upload_media at the end. An agent can decide between URL-based and base64 uploads without opening either 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?

Names the alternative (wp_upload_media) and the exact condition that selects it ('file content at hand'), and implies this tool for remote files. The exclusion of private/internal hosts and of HTML/SVG/XML/script content further bounds when calls will fail.

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