socials_fetch_image

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

No annotations provided, so the description carries the full burden. It discloses return format (MCP image content + JSON metadata), prerequisites (Socials Pro + extension), and URL restrictions (public URLs, cookie-gated issues). Lacks details on error handling or size limits but is generally transparent.

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?

Description is concise and front-loaded with the core purpose, followed by cost guidance, prerequisites, and limitations. All sentences earn their place, though slightly wordy in the requirements sentence.

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 one parameter and no output schema, the description compensates by explaining return format, cost implications, and limitations. It is fairly complete for a simple tool, but could mention error behavior or metadata specifics.

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 minor nuance about public vs cookie-gated URLs, but does not significantly enhance the parameter meaning beyond the schema description.

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 tool downloads an image by URL and returns it for visual inspection, with a specific verb and resource. It distinguishes from sibling tools by being the only one focused on image fetching.

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?

Explicitly tells the agent when to use (only when visual inspection materially improves the answer) and when to avoid (prefer URLs/text metadata when sufficient). Also notes limitations like cookie-gated images needing another approach.

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