Pagebolt

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions the return type ('Returns an image') but lacks critical details: whether this is a read-only operation, if it has rate limits, what happens with invalid inputs, authentication requirements, or error behavior. For a 12-parameter generation tool, this leaves significant behavioral gaps.

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 perfectly concise - two sentences that directly state the tool's function and return value with zero wasted words. It's front-loaded with the core purpose and efficiently communicates the key capabilities without unnecessary elaboration.

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 complex 12-parameter image generation tool with no annotations and no output schema, the description is incomplete. While it states what the tool does, it lacks crucial context about the returned image format, error handling, authentication needs, and practical usage scenarios. The high parameter count and generation nature demand more comprehensive guidance than provided.

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 already documents all parameters thoroughly. The description adds minimal value beyond the schema - it mentions 'built-in templates or custom HTML' which aligns with the template and html parameters, but doesn't provide additional semantic context. This meets the baseline for high schema coverage.

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 specific action ('Generate') and resource ('Open Graph / social card image'), distinguishing it from siblings like generate_pdf or take_screenshot. It explicitly mentions both built-in templates and custom HTML options, providing a comprehensive purpose statement.

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 provides no guidance on when to use this tool versus alternatives like generate_pdf or take_screenshot. It doesn't mention prerequisites (e.g., Growth plan+ for HTML), typical use cases for social cards, or when to choose templates over custom HTML. The agent receives no contextual usage instructions.

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