Make every social and web size from one image

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

With no annotations, the description carries the full behavioural burden. It usefully discloses the output location ('Files go to the output folder named after each preset') and warns that some banner sizes crop differently per device, but it says nothing about what happens when an output file already exists (the schema's overwrite default implies a possible failure or skip), whether the operation is idempotent, or what filesystem access is required.

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 core verb and the output list, then the fit guidance, then the crop caveat. Dense but every clause carries usable information. The preset enumeration is long but directly maps to the enum values, so it earns its space; the device-crop advice is the only sentence bordering on advisory padding.

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 6-parameter, no-output-schema, no-annotation tool, the description covers purpose, fit choice, preset scope, and output destination adequately. The gaps are behavioural rather than definitional: how overwrite=false is handled, whether pad_color only applies in pad mode, and what the tool returns (paths? a manifest?) are not conveyed.

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 50%, and the description compensates well for the two most consequential parameters: the three fit modes are explained in richer, more practical terms than the schema ('contain … whole image on a blurred copy of itself, logos and posters'), and the preset families are grouped by platform. It adds no meaning for pad_color, overwrite, or input_path beyond what the schema shows, which keeps it below 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?

Specific verb and resource: 'From one image, makes the sizes people need', followed by a concrete enumeration of the platforms and formats produced (Open Graph, LinkedIn, X, Instagram, YouTube, favicon/app icons). An agent can immediately tell this is a batch resize/export tool and distinguish it from siblings like image_generate or compose.

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 useful guidance on which fit mode to choose (cover for photos, contain for logos and posters, pad for solid colour) and a centring tip for Facebook/YouTube crops, which implicitly tells the agent when each mode applies. However, it never states when to use this tool rather than a sibling such as compose, image_generate, or media_optimize, and no exclusions or prerequisites are given.

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