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

Annotations indicate readOnly=false but the description goes further, disclosing that the tool creates the watch if new, returns the amount and observation count, and refuses unreadable prices. This adds meaningful behavioral context beyond the structured annotations.

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 two sentences with no filler. It front-loads the core purpose, follows with the key side effects and limitations, and tucks the quota at the end. Every sentence earns its place.

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 simple write tool, it covers the core behavior, side-effect of watch creation, return values, and a refusal condition. The schema handles parameter details, and the description is sufficient to use the tool correctly. A small gap is that error handling beyond 'unreadable price refused' is not described, but that is minor.

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 100% and each parameter already has a clear description, including a price format example. The tool description does not add parameter-specific nuance, but the schema fully carries that burden, so a baseline 3 is appropriate.

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 a specific verb-resource pair: manually store a price when a shop blocks automated fetching. It also explains a key side effect (creates the watch if new) and differentiates itself from fetching-oriented siblings like price_check.

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?

Explicitly tells the agent when to use this tool: when a shop blocks fetching, and why (manual reading). It also adds a limitation ('An unreadable price is refused') and a quota note ('Free: 3 watches'). It doesn't name an alternative tool explicitly, but the 'blocks fetching' condition clearly distinguishes it from price_check.

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