Add allowed site

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

Annotations already declare readOnly=false, idempotent=true, destructive=false, so safety is partly covered. The description still adds substantive behavior beyond them: subdomain matching semantics, that an existing pattern is reused unchanged, and that the saved rule is returned. Auth specifics beyond 'user-authorized' are not detailed, keeping it from a 5.

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?

Four short sentences, each carrying distinct information: purpose, alternatives, matching semantics, return/idempotency, and scope limit. No filler and front-loaded with the core action.

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 one-parameter mutation with annotations and no output schema, everything an agent needs is present: what to pass, how patterns match, that repeated calls reuse a rule, what is returned, and what the call does not do.

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 coverage is 100% and the single parameter already has an example-based description. The description goes further by explaining what 'plain hosts' vs 'wildcard patterns' mean for matching, which is meaning the schema does not provide.

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 hostname pattern to the webpage-capture allowlist') and explicitly distinguishes the tool from list_allowed_sites and remove_allowed_site, so an agent can tell it apart from siblings without inspecting 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?

Names when to use it ('a user-authorized uoink_page destination') and the alternatives for inspecting and revoking rules. It also adds the key scoping note that this grants future access but does not capture a page, preempting misuse.

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