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

With no annotations, the description carries the full burden. It usefully discloses a non-obvious behavioral trait: existing baselines are returned without refetching (idempotent/cached behavior). However, it omits auth requirements, rate limits, cost implications, and what happens on conflicting selector/ignore inputs.

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 tight sentences, front-loaded with the primary action and followed by an important constraint. Little waste, though the second sentence could be trimmed slightly.

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?

For a four-parameter tool with no annotations and no output schema, the description covers only the caching behavior. It leaves parameter semantics and behavioral context largely unexplained, so an agent would need the raw schema to call it correctly.

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 0% across four parameters (url, selector, ignore_selectors, ignore_json_paths), so the description must compensate but does not. It only references the conceptual outputs (baseline, watch_id) and explains none of the input parameters' meaning or format.

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?

Clear verb+resource: it states it creates or retrieves a Fresh402 baseline and a persistent watch_id. It hints at the sibling's territory (repeated change checks) but never names fresh402_check, so differentiation is implied rather than explicit.

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?

It gives a negative constraint ('cannot be used as a free repeated change check'), which points toward the alternative without naming it. There is no explicit when-to-use statement or reference to fresh402_check, leaving routing to inference.

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