custom_css_update

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

With no annotations, the description carries the full burden and delivers: it discloses that changes go live on the published version immediately, that the whole stylesheet is overwritten, and that a local backup is taken beforehand. It omits auth/permission requirements and how/where the backup can be restored, which keeps it just short of a 5.

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?

Five short sentences, each carrying a distinct operational fact, with the core action front-loaded and the safety steps following. No repetition or filler.

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 destructive two-parameter mutation with no output schema, the description covers liveness, full-overwrite semantics, backup, and required merchant confirmation. It leaves version_id semantics and permission requirements implicit, but nothing essential for a correct call is missing.

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%, so baseline is 3, but the description adds real value by stressing that css must be the complete stylesheet and not a fragment. version_id is left entirely to the schema, so it stops short of full 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?

States a specific verb and resource ('Replace the store's entire custom CSS') and makes the replacement semantics explicit versus a fragment edit. The read-before-write instruction implicitly distinguishes it from custom_css_get, so an agent can tell the full-overwrite tool apart from the read tool 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 explicit procedural preconditions: 'Always read the current CSS first', 'pass the full new stylesheet (not a fragment)', and 'get their OK before calling'. These are concrete when/how conditions that route the agent correctly and name the read sibling implicitly.

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