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

With no annotations, the description must carry the full behavioral burden, and it does disclose genuinely useful traits: the call blocks/waits rather than returning immediately, and it validates the link host against `site` plus trusted subdomains. It omits what happens on timeout or mismatch, whether a default timeout applies, and what the caller observes on failure, so it is not fully transparent for a blocking operation.

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 short sentences, front-loaded with the action, with no filler. 'site is required' partly duplicates the schema's required list, a small redundancy but a defensible emphasis given the low schema coverage.

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 4-parameter, annotation-free, output-schema-free blocking tool, the description covers purpose and domain-matching behaviour but leaves out timeout semantics, error/timeout outcomes, and the meaning of `cdp_url`. An agent could call it, but would be guessing about failure handling and the browser connection parameter.

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 25% — just `identity_id` is documented. The description adds real meaning for `site` (it is the expected link host, not a URL to visit), but it never explains `cdp_url` (apparently a browser connection endpoint) or the bounds/behaviour of `timeout_seconds`, leaving two of four parameters opaque in both schema and description.

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 compound action: wait for a magic link and open it, scoped to links whose host is `site` or a trusted subdomain. This is distinguishable from siblings like wait_for_email_code or fill_code, which return or submit codes rather than opening a link. It does not explicitly name a sibling it differs from, which keeps it at 4.

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?

There is no explicit when-to-use guidance, no mention of prerequisites (e.g. that a magic-link email must already have been triggered), and no routing to alternatives such as wait_for_email_code or fill_email_code. The only conditional information is a restatement that `site` is required.

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