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

No annotations are provided, so the description carries the full behavioral burden. It adds genuinely useful context by disclosing billing ('Costs $0.005 USDC'), which is exactly the kind of trait annotations cannot express. However, it says nothing about whether the check is read-only, how results behave for caller-supplied resources, or how max_age_seconds/caching affects whether a live fetch occurs.

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?

Three short sentences with no filler, and the purpose is front-loaded ahead of cost and prerequisite. Every sentence carries distinct, non-redundant information.

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 an 8-parameter, no-annotation, no-output-schema tool, coverage is thin: the description covers purpose, price, and prerequisite ordering but leaves the entire parameter surface and the shape of the change result (changed yes/no, diff, hash) undocumented.

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?

There are 8 parameters with 0% schema description coverage, so the description must compensate and largely does not. It only hints at the watch_id-versus-url distinction via 'registered or caller-supplied'; selector, include_diff, previous_hash, max_age_seconds, ignore_selectors, and ignore_json_paths are completely unexplained in both the schema and the description.

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 ('Check whether a ... web resource changed') and scopes it to two modes ('registered or caller-supplied'), which immediately separates it from the sibling fresh402_register that only creates baselines. An agent can tell what the tool does without opening the 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 sibling and the condition that selects it: 'Use fresh402_register first for a free baseline when starting a new watch.' That is real routing guidance. It stops short of explaining when to pass watch_id versus url/selector, and names no exclusions, so it is clear but not complete.

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