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

With no annotations, the description carries the full behavioral burden and does so richly: 5-15s latency, a 50/day shared budget, single-flight concurrency, rate-limit failures, no page rendering (so visual/DOM signals come back unevaluated in analysis_failures), full-URL privacy/logging implications, and an attacker-authored-data warning. This is exactly the context annotations would otherwise supply.

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?

It is a dense block, but it is front-loaded with the core distinction and nearly every clause (slow, limited, no-render, privacy, injection) earns its place. Slightly heavy for a one-parameter tool.

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?

Complete for a slow, rate-limited, actively-fetching tool with no output schema: it discloses cost, concurrency, failure modes, what the response will and won't evaluate, and data-safety caveats. Nothing an agent needs to call it correctly 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% for the single parameter and the schema description already states the URL will be contacted and that a bare domain is preferred. The prose largely restates that guidance rather than adding new syntax or format detail, so the baseline of 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 ('ACTIVE deep analysis of a URL') and immediately contrasts it with the sibling analyze_url, which it explicitly says NEVER contacts the target. An agent can distinguish the two without opening either schema.

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 the alternative (analyze_url) and the precise condition that selects this tool ('only when analyze_url's passive signals are inconclusive'), plus an explicit exclusion ('NOT a default first call'). When-to-use and when-not are both stated.

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