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

Annotations already cover read-only, idempotent, and non-destructive traits. The description adds behavioral value by disclosing the output contents and the CDN/firewall insight, which is not deducible from annotations alone. No contradictions.

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 sentences, no filler. The first sentence front-loads the purpose and the second delivers the unique selling point. Every word earns its place, and the structure is immediately scannable.

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 tool is simple (2 params, no output schema). The description covers what it returns and its unique behavioral advantage. An agent can confidently select and invoke it without further clarification.

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 50% (domain has a description; agent only has an enum). The tool description lists the agent values redundantly with the enum and mentions 'as a named crawler', but adds no new syntax or constraints beyond what the schema already states. For a two-parameter tool with self-explanatory enum, this is adequate but not enriched.

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 (fetch) and resource (root page as a named crawler), and enumerates the exact output (status, redirects, headers, extracted text). It clearly distinguishes from siblings by emphasizing it shows CDN/firewall blocks that robots.txt cannot, which implies a unique value proposition.

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?

Provides clear context on what the tool reveals (what a specific bot receives, including blocks beyond robots.txt). It does not explicitly name alternatives or exclusions, but the description makes the use case self-evident against siblings like check_discoverability.

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