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

Annotations already flag destructiveHint=true and idempotentHint=false, and the description reinforces and enriches this: deep-merge vs. REPLACE semantics for strings/arrays, unsetProps branch dropping, the 'src shadows content' image pitfall, and the ROOT inject.head/footer caveat. This goes well beyond what annotations convey.

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 core scope and sibling differentiation, then packed with high-value semantics. It is dense and slightly run-on, but nearly every clause carries operational weight; only minor reordering into clearer sentences would help.

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 an 11-parameter destructive mutation with no output schema, the description covers merge/replace behavior, deletion semantics, image pitfalls, and child-node exclusion. It omits error/rollback behavior and permission requirements, but nothing critical to invoking it correctly 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?

Although schema coverage is 100%, the description adds real meaning the schema lacks: propsPatch deep-merges listed branches but strings/arrays replace, classNamePatch uses twMerge, typePatch swaps component type with isCanvas following, and it points to get_site_node to read current values before patching.

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?

Names a specific verb+resource (patch one node) and immediately distinguishes scope from its sibling ('several: patch_site_bulk, one atomic write'). The classNamePatch/propsPatch/typePatch breakdown makes the operation concrete without opening the 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?

Explicitly routes multi-node edits to patch_site_bulk, states the when-not ('Children are not accepted'), and refers to get_style_reference({topic:'editing'}) for further guidance. Alternatives and constraints are named directly.

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