create_og_image

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

No annotations are provided, so the description carries the full burden. It does add genuine behavioral facts: fixed 1200x630 dimensions and that the result is returned visually rather than, say, written to disk. But it is silent on how the image is delivered (URL vs. attachment), whether an external rendering service or cost is involved, and any failure behavior.

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?

A single 14-word sentence with no filler. The verb, artifact, dimensions, and output modality are all front-loaded and every element earns its place. This is genuine conciseness, not under-specification.

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?

With no output schema and no annotations, the description should clarify return semantics; 'return it visually' is vague about how the agent or user actually receives the image. For a simple, fully schema-documented 4-parameter tool the core invocation is understandable, but the return contract and any prerequisites/limitations remain under-specified.

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% and each property already has a meaningful description (theme enum with default, title, siteName default, subtitle). The tool description adds no parameter-level meaning beyond what the schema provides, so the baseline of 3 applies.

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 names a specific verb ('Generate'), a concrete artifact ('branded 1200x630 Open Graph social card'), and an output modality ('return it visually'). This is clear and more informative than the tool name alone, and the artifact type implicitly separates it from image siblings like render_screenshot and code_image, though it never explicitly contrasts them.

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?

There is no explicit when-to-use or when-not-to-use guidance and no mention of alternatives. The only usage signal is implied: the term 'Open Graph social card' suggests a social-sharing meta-tag scenario. That is enough to count as implied usage, but the agent gets no help choosing between this and the sibling rendering tools.

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