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

Annotations cover the safety profile (not read-only, not destructive, closed-world), so the bar is lower. The description adds genuinely non-obvious behavior: the block re-themes against the current site, so the result is expected to differ from the catalog thumbnail — a meaningful expectation-setter that prevents false bug reports.

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?

Three sentences, front-loaded with the action and the preference rule, then the theming caveat. Slightly long final sentence but every clause carries useful information.

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, the description should set expectations about the result, and it does so via the theming explanation. It omits what the call returns (e.g., new component path) and whether the insert is undoable, which are minor gaps for a page-mutating tool.

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%, including the nested adaptations object and its subfields, so the baseline is 3. The description only says content can be 'optionally customized' and adds no syntax or semantics beyond what the schema already documents.

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: insert a pre-built block from the catalog, with optional content customization. It also frames the alternative verb ('generating from scratch'), which helps agent selection, though no sibling tool is named explicitly.

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?

'STRONGLY preferred over generating from scratch when a matching block exists' gives clear, actionable selection guidance. It stops short of the obvious workflow prerequisite (e.g., using swebsy_list_blocks to find a matching block) or any when-not-to-use condition.

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