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

Annotations already declare this is a non-destructive, idempotent, non-open-world write, so the description needn't re-state the safety profile. It adds genuine behavioral context the annotations lack: that ownership must still be verified in Search Console before any data appears, which sets expectations about a successful call having no immediate visible effect. It does not say what happens on an already-existing or invalid URL beyond what idempotentHint implies.

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 short sentences with zero waste. The action is front-loaded and the caveat follows immediately, so an agent reading only the first clause still knows what the tool does.

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 a single-parameter write with no output schema and annotations carrying the safety profile, this covers the essential gotcha (verification happens out-of-band). Slightly incomplete in that it never says whether the call fails or no-ops on a duplicate property or an unverified URL, which matters for a mutation 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%, and the siteUrl documentation is unusually strong, giving both accepted forms and cross-referencing gsc_list_sites as the canonical source. The description adds no parameter meaning of its own, so the baseline 3 applies.

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: "Add a property to Google Search Console." An agent can distinguish it from gsc_list_sites and gsc_delete_sitemap without opening schemas, since those are list/delete operations. It stops short of naming a sibling explicitly, so it does not reach full sibling differentiation.

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?

Usage is implied by the verb "Add" and the verification caveat, which tells the agent that adding alone will not produce data. There is no explicit when-to-use vs. when-not guidance, no mention of how this interacts with gsc_list_sites to check for existing properties, and no stated prerequisites for the caller's account.

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