effects

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses that the source remains unchanged and output is written to a new file, states the return values (output path and effect applied), and warns that unknown effect names raise an error. It does not reveal edge cases like overwriting behavior for an existing output file, but the disclosed side effects and error handling are solid.

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 a single, information-dense sentence followed by a bullet-style list of effects and their parameter usage. Every sentence earns its place: the core purpose, the side effect, the list of effects with parameter ties, the return values, and error behavior are all covered without fluff. It is front-loaded and easy to scan.

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?

Given the tool's complexity (5 parameters, no output schema, no annotations), the description covers the essential operation: effects list, parameter associations, return behavior, and error handling. It does not address details like what happens when the output file already exists or supported image formats, but these are minor gaps given the schema covers parameter semantics and the description handles the core usage.

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 description coverage is 100%, so the schema fully documents all parameters including the purpose of 'factor' and 'radius'. The description adds a mapping between effects and parameters ('blur uses radius', 'contrast/brightness use factor'), but this is redundant with the schema's own descriptions. The description does not add meaningful new semantics beyond what the schema already provides.

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 states a specific verb 'Apply' with an explicit resource ('visual effect') and enumerates the exact effects (greyscale, sepia, invert, blur, sharpen, contrast, brightness). It clearly distinguishes from sibling tools (resize, crop, convert, etc.) by focusing on effects, and the phrasing 'apply a single visual effect' leaves no ambiguity about the tool's role.

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 implies usage when a visual effect is needed, but it does not explicitly state when NOT to use this tool or mention alternatives. It provides no guidance on selecting between sibling tools (e.g., convert for format changes vs. effects for filters), so the usage context is only implied rather than explicitly defined.

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