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

Annotations already declare this as read-only and idempotent, so the safety profile is covered. The description adds behavioral detail by stating results are 'ranked matches' and enumerating exactly what each match includes, which goes beyond the structured annotations.

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 sentences, each earning its place: purpose and scope, output contents, and handoff to the sibling tool. The most important decision signal, 'canonical key is unknown,' is front-loaded.

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?

The description is complete for a search tool with a rich output schema and fully documented parameters. It covers what the tool does, what it returns, and how to continue the workflow with browsercompat_get_feature, leaving no critical gap for an agent.

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%, so the input schema already documents query, limit, baseline, and namespace. The description reinforces that query is a plain-language name or keyword, but it does not add meaningful parameter semantics beyond the 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 states a specific verb and resource: 'Find web features by plain name or keyword when the canonical key is unknown.' It clearly distinguishes itself from browsercompat_get_feature, which is the exact-key lookup, and lists the covered technology areas and return fields.

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?

The description explicitly defines when to use this tool: when the canonical key is unknown. It also routes the caller to browsercompat_get_feature for the full record, giving a clear alternative action after search results are returned.

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