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

Annotations already declare openWorldHint=false, destructiveHint=false and idempotentHint=false, lowering the bar. Against that, the description adds genuinely non-obvious semantics: notices in the result are non-fatal, report template problems for review, and do not undo the created design. It does not mention that repeated calls create duplicate designs (consistent with idempotentHint=false), which is a minor omission.

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?

Four short sentences, front-loaded with the verb and resource, and each subsequent sentence adds a distinct piece of information (setting ownership, template format reference, non-fatal notices). No repetition of schema or annotation content.

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?

An output schema exists, so return-value explanation is not required, and the description already covers the one output behavior that matters: notices are warnings, not failures. Parameter schema and annotations cover the rest. A minor gap is the absence of any statement about duplicate designs on repeated calls, given idempotentHint=false.

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 every nested field (Title, Images.{LogoURL,Favicon32URL,Favicon180URL}, Templates.{SharedHeader,Landing,Post,Archive,Tag}) is documented in the schema. The description only names the three top-level parameters and adds the pointer to blog_design_template_format, so it contributes marginal meaning beyond the schema. Baseline 3 is appropriate.

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 opening sentence states a specific verb and resource ('Create a new blog design') plus the three required inputs, so the tool is instantly distinguishable from reads like get_blog and blog_design_list. It also clarifies that blog title/description belong to get_blog/update_blog, which separates it from settings tools. The one gap is that it never distinguishes itself from blog_design_edit or blog_design_save, leaving an agent to infer create-vs-save semantics.

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?

It gives a real usage boundary: title and description are blog settings handled elsewhere, so this tool should not be called to rename or re-describe a blog. It also routes the agent to blog_design_template_format for template syntax. There is no explicit statement of when to use this over blog_design_edit or blog_design_save, so it stops short of a full routing guide.

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