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

Adds real context beyond the annotations: a confirmation email is sent and is not confirmed by this tool, and a Bearer API key or session token is required for auth. These are the two facts an agent most needs before calling. It stops short of saying what happens if the product resolves ambiguously or when the watch becomes active.

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 short sentences, front-loaded with purpose, then behavior and auth. No filler. It could have spent its remaining space on parameter precedence rather than nothing, but nothing written is wasted.

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 eight-parameter, zero-required mutation with no output schema, the description covers auth and the confirmation-email side effect but not the return value or how the many product-identifier parameters interact. Adequate to attempt a call, thin for calling it correctly on the first try.

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 88%, so the baseline is 3. The description mentions the URL/id and optional target price but does not resolve the eight overlapping identity inputs (url, product, productId, query, marketplace) or indicate precedence when several are supplied, which is the main ambiguity the schema leaves.

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 ("Start watching a product") plus actor scope ("for the signed-in user") and the identifying inputs (URL or id, optional target price). It is clearly distinct from remove_watch, list_watches, and get_price_history, though it does not name a sibling explicitly.

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?

Usage is implied by the create-a-watch purpose rather than stated as when/when-not guidance. There is no routing to remove_watch to stop tracking, to list_watches to check status, or to search_products when the product has not been identified yet — the closest signal is the schema's query parameter, not the description.

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