add_custom_webpart

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. 'Add' implies a mutation, but the description says nothing about side effects, required permissions, whether the page must be unpublished, or what happens on failure. It is only marginally more informative than a bare operation name.

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?

The description is a single front-loaded sentence with no wasted words, but for a tool requiring five parameters and performing a page mutation, it is under-specified rather than appropriately concise. Structure is fine; substance is missing.

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?

Against a tool with five required parameters, no annotations, no output schema, and only 20% schema description coverage, the description is inadequate. It does not explain where the web part is placed (section/column), what the JSON must contain, or what success looks like.

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 only 20%, so the description must compensate for the four undocumented parameters (siteId, pageId, sectionIndex, columnIndex). The phrase 'from a JSON definition' loosely corresponds to webPartJson, but adds no guidance about the required IDs, index values, or expected JSON structure.

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 description states a specific verb and resource: 'Add a custom web part from a JSON definition.' That is clear enough to distinguish it from sibling tools like add_image_webpart or add_text_webpart, which are type-specific. It does not explicitly name or contrast those siblings, so it falls short of a 5.

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?

No when-to-use guidance is provided. The word '(advanced)' hints at a use case but does not state when an agent should choose this tool over add_image_webpart, add_text_webpart, or other web-part insertion tools, nor does it mention prerequisites such as page edit permissions.

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