generate_image

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

Annotations provide minimal behavioral context (readOnlyHint=false, idempotentHint=false). The description adds meaningful context beyond annotations: it states the return format ('inline PNG for the GUI/chat') and an auth requirement ('Requires an OpenAI image API key'). It does not contradict annotations, so no annotation contradiction.

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 three sentences, front-loaded with the purpose, followed by usage guidance, an alternative, and a requirement. Every sentence provides distinct value with no unnecessary fluff, making it highly concise and well-structured.

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 has 5 parameters with a fully descriptive schema, the description covers the key contextual elements: what it does, when to use it, a critical alternative, an auth prerequisite, and the output format. It does not explain error handling or cost, but for a simple generative tool with rich schema, this is sufficiently complete.

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%, with all five parameters having descriptions. The description itself does not elaborate on parameter details but does mention 'text prompt' and 'return as PNG', adding slight context. Since the schema already documents parameters thoroughly, a baseline score of 3 is appropriate.

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 says 'Generate a new visual image artifact from a text prompt and return it as an inline PNG for the GUI/chat.' This is a specific verb+resource statement that clearly defines the tool's function. It also distinguishes itself from sibling system data tools by noting a preference for chart-returning metric tools for system data, making its purpose unambiguous.

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 explicitly states when to use this tool: 'Use when the user asks for an image or when a small visual artifact would clearly make the answer more useful.' It also provides an exclusion: 'Prefer built-in chart-returning metric tools for system data.' This gives clear guidance versus alternatives and includes a prerequisite (OpenAI API key).

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