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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description adds useful domain context instead: where add-ons live and what the result includes (on/off status and settings). It does not add auth, freshness, or rate-limit details, but for a simple read tool with strong annotations this is solid.

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?

Two sentences, front-loaded with the resource and its concrete examples, followed by scope clarification and an explicit exclusion. The enumeration is long but earns its place by making the concept unambiguous.

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 adequately says what comes back (whether each add-on is on plus its settings). It also prevents the most likely misuse by ruling out page-editing tools and the chat widget. A mention of manage_site_addon for changes would make it fully complete.

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 the descriptions already explain site_id ('from list_sites') and user_goal. The prose adds no parameter-specific meaning beyond that, so this sits at the baseline for a fully documented schema.

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 uses a specific verb and resource ('built-in add-ons placed on a site') and enumerates concrete examples, making the scope unmistakable. It also explicitly distinguishes this from page-editing tools and from the chat widget, so an agent can tell it apart from siblings without opening schemas.

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 clear context for when to use this tool: add-ons live on the site record, not in page code, so page-editing tools cannot find or change them. It also names the chat-widget alternative to avoid. It stops short of explicitly routing mutations to manage_site_addon, which keeps it from a 5.

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