markitup_extend

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

Without annotations, the description carries the full burden. It mentions the credit cost but does not disclose other behavioral traits such as output format, synchronous/asynchronous behavior, error conditions, or whether the operation is reversible. The description provides minimal behavioral context beyond the basic action.

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 extremely concise with two sentences that front-load the purpose and immediately follow with usage context and parameters. No redundant or unnecessary information is present.

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 complexity (7 parameters, no output schema, no annotations), the description covers the essential purpose and usage but lacks details on output format, direction of extension, or error handling. It is adequate for a basic understanding but not fully comprehensive.

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?

The schema has 71% description coverage, so the description's added value is limited. It reiterates that parameters include source image (URL or base64) and target dimensions, but does not explain the 'image_size' enum or add semantics beyond what the schema already provides. This meets the baseline for moderate 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 tool's purpose: 'AI-outpaint an image to a larger canvas.' It provides specific use cases like converting a square asset to different aspect ratios, which distinguishes it from sibling tools that generate, regenerate, or remove backgrounds.

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 explicit use cases ('converting a square asset to 16:9 or 9:16, or extending a tight crop') and mentions cost ('Costs 1 credit'). However, it lacks explicit comparison to alternatives or when not to use it, though the context from sibling names implies differentiation.

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