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

The description goes well beyond annotations by explaining non-destructive behavior ('Nothing is edited in place'), temporary storage of the new image, and the risk of repainting baked-in text on flat images. This enriches the readOnlyHint=false and destructiveHint=false annotations with specific side-effect context and is fully consistent with them.

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?

All sentences carry weight. The description front-loads the core purpose, then structures warnings and usage with clear labels (USE FOR, OUTPUT). It is longer than average but every section earns its place, covering alternatives, side effects, and follow-up actions without redundancy.

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?

The tool has no output schemaapperance, yet the description explains exactly what is returned (new image URL), whether the original is mutated (no), and what to do with the result (upload_image_creative). It addresses edge cases (flat vs layered creatives), making it complete for an agent to invoke correctly and handle the outcome.

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 baseline is 3. The description adds no extra parameter-level semantics: the schema already describes image_source as 'background image to edit', edit_instruction as natural-language, and domain as brand context. The tool description restates the background scope but does not provide syntax or format details beyond the schema.

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 opens with a precise verb-resource pair: 'Apply a free-text AI edit to a flexible creative's BACKGROUND image and return the edited image URL.' It clearly distinguishes itself from siblings like edit_brand_creative by scoping to background images only and explicitly states the output type. The resource and action are 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 gives concrete when-to-use examples (USE FOR: 'remove the glare', etc.), names the alternative behavior (edit_brand_creative), and provides an exclusion (layered creative text should be changed via text layers, not this tool). It also routes to upload_image_creative when persistence is needed, making selection and sequencing explicit.

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