List allowed sites

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description goes well beyond that by disclosing negative capabilities ('does not test reachability or fetch pages') and a non-obvious data fact ('Seeds can be removed like other entries'), which prevents an agent from assuming listing validates access.

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 tight sentences, front-loaded with the purpose, then routing guidance, then return shape and behavioural caveats. No filler; every clause carries information an agent would otherwise have to infer.

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?

Despite having no output schema, the description summarises the return payload (sites, count, default seeds) and rules out a plausible false expectation about reachability testing. For a read-only single-parameter list tool, nothing material is missing.

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% with a fully documented single parameter (active_only), so the schema does the heavy lifting. The description's phrase 'and their active state' hints that an active flag exists but adds no semantics about the active_only filter beyond the schema. 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: 'List saved webpage-capture hostname patterns and their active state.' That immediately distinguishes it from add_allowed_site and remove_allowed_site, and the closing sentence names the concrete return fields (sites, count, default seeds).

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?

Gives an explicit pre-condition use case ('Use before uoink_page to check access') and names the alternative tools for mutation ('use add_allowed_site or remove_allowed_site to change the allowlist'). Both when-to-use and which-sibling-to-use-instead are spelled out.

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