URL Changed

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

The description discloses side effects (creates a baseline on first use), caching behavior, and that JavaScript is not executed. It also notes SSRF-sensitive destinations are rejected, which aligns with annotations and provides additional safety context. Annotations indicate readOnlyHint=false, consistent with the described stateful behavior.

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 description is concise, with the main purpose front-loaded. Every sentence adds value, with no redundancy or unnecessary words.

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?

Given the tool's simplicity (2 parameters) and the existence of an output schema, the description fully covers purpose, behavior, usage guidance, parameter semantics, and safety considerations. No gaps remain.

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 description adds meaningful context beyond the schema: explicitly stating the URL must be absolute and public, and explaining the fresh flag's effect on caching and origin load.

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 clearly states the tool compares a URL's content hash against a previously stored baseline, creating a baseline on first use. It reports whether content changed and returns hashes with timestamps. This distinguishes it from siblings like url_diff (which compares two URLs) and other url_* tools.

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 provides clear guidance on when to use the tool (to detect changes) and explicit instructions for the fresh parameter ('Keep fresh=false to reuse cache; set fresh=true only for a new fetch'). It does not explicitly state when not to use it, but the context is sufficient.

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