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

Annotations only carry the safety flags (destructive, idempotent, openWorld); the description adds what those flags actually mean in practice: writes land in Shopify immediately, items succeed or fail independently, and failures are reported per id. It also discloses that an empty string clears the alt, which is the destructive path an agent needs to know about.

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?

Front-loaded with the batch limit and write behavior, and every sentence carries information. The 'Same rules as update_image_alt' clause then restates the 125-character/clearing rules that already appear in the schema, which is mild 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?

For a 1-parameter bulk mutation with an output schema present, the description covers everything an agent needs: id provenance, the mandatory get_image step, partial-failure semantics, and authoring rules. Return values need not be explained since the output schema exists.

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% and both nested fields are documented there, so the baseline is 3. The description adds a real constraint beyond the schema: the 125-character authoring rule (stricter than the schema's maxLength of 512) plus content rules (no 'image of', no keyword stuffing). That the two limits disagree is worth resolving, but the added semantics are genuine.

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?

States a specific verb (Set), resource (alt text), batch scope (up to 50 images in one call), and the id source. The reference to update_image_alt makes the single-vs-bulk split inferable, so an agent can separate it from its closest sibling without opening either schema.

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?

Gives concrete prerequisites: image ids come from get_resource, and the agent must call get_image BEFORE writing each alt, with a reason (alt guessed from a product title describes the product, not the picture). It stops short of an explicit 'use update_image_alt for a single image' routing statement, but the when-to-use context is clear.

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