watch_listing

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

No annotations are provided, so the description carries the full burden. It discloses that it's FOSS (no paid service), that it watches for price drops, and that check_watch must be re-run later. However, it doesn't state side effects (e.g., whether a watch record is created, duplication behavior) or prerequisites (like auth), leaving some behavioral gaps.

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 compact sentences. It front-loads the core purpose ('Watch a SINGLE listing for a PRICE DROP'), then adds the FOSS note, the follow-up action (check_watch), and platform support. Every word earns its place with no redundancy or padding.

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 3-parameter, 1-required tool with no output schema, the description is fairly complete. It explains the purpose, the necessary follow-up, and supported sources. It omits details like what happens on success or error, but these are minor given the tool's simplicity and the availability of sibling tools for auth and listing checks.

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?

The input schema has 100% description coverage, so each parameter (url, name, listingId) is already documented with clear purpose and examples. The description adds context (supported platforms) that helps interpret the url parameter but does not introduce new parameter-level semantics beyond what the schema provides. 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 uses a specific verb 'Watch' with a precise resource 'a SINGLE listing' and a concrete goal 'for a PRICE DROP'. It clearly distinguishes from sibling tools like watch_search by emphasizing 'SINGLE', and it specifies supported platforms (carsales, Facebook, Gumtree), leaving no ambiguity about what the tool does.

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 explicitly directs the user to re-run check_watch later to see price changes, establishing a clear workflow. It implies a use case (single listing vs. search) by emphasizing 'SINGLE', but does not explicitly name watch_search as the alternative for search-based watches. However, the context and sibling list make the intended usage fairly clear.

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