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

With no annotations, the description carries the full burden and does so richly: passive/no-contact behavior, automatic queuing of suspicious domains for pipeline analysis, privacy disclosure that the full URL is transmitted and logged and may later be fetched, and an attacker-authored-data warning against prompt injection.

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?

The purpose and 'Read verdict first' are front-loaded well, but the remainder is a single dense paragraph of ~250 words cramming field-by-field semantics into prose. The content earns its place for a no-output-schema tool, yet it is more sprawling and harder to scan than necessary.

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?

There is no output schema, so the description must explain returns, and it does: verdict + confidence + basis, live_analysis.url_risk with its warning not to treat it as a verdict, external_feeds with listed_scope and freshness, and historical apex detections. Nothing an agent needs to interpret or call the tool 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% and the schema already explains the single url parameter, so baseline is 3. The description adds real routing value by advising a bare domain when tokens are present, going slightly beyond the schema's own wording.

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+resource ('Analyze any URL'), names the domain (phishing signals), and pins the scope with 'WITHOUT contacting it (passive)', which immediately separates it from analyze_url_deep. It also names check_domain as the routing alternative, so an agent can distinguish it from siblings without opening a 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?

Gives explicit alternative routing ('pass a bare domain, or use check_domain, when the URL carries tokens or credentials') and instructs the agent to read verdict first. It lacks any explicit when-to-prefer-this-over analyze_url_deep (passive vs deep), so it stops just short of full when/when-not coverage.

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