billwatch

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

With no annotations, the description carries the full behavioral burden, and it does disclose the return content (dated snapshots of monthly price and billing terms), which implies a read operation. However it says nothing about permission requirements, how far back the history goes, snapshot count, or pagination, leaving notable behavioral gaps for a zero-annotation tool.

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: purpose and output shape front-loaded, then the dependency for obtaining the input. No filler or redundancy.

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 single-parameter read tool with no output schema, the description adequately covers what it does and what it returns, compensating somewhat for the missing output schema. It could be more complete by noting the history's coverage window or any rate/recency constraints.

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 is only one parameter and schema coverage is 100%, so the schema already documents plan_id with an example. The description reinforces that it takes a single plan id but adds no format or constraint detail beyond the schema, making the baseline 3 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?

States a specific verb and resource ('Pricing changes over time for one BillWatch plan') and immediately clarifies the return shape ('dated snapshots of the listed monthly price and billing terms'). It is clearly distinguishable from the sibling search_deals, which is named as the id-lookup path rather than a competitor for this data.

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 routes the agent to search_deals to obtain the required plan_id, which is real actionable guidance for the one input. It does not, however, state when this tool should be used versus not used (e.g., recency limits or scope exclusions), so guidance is clear but not exhaustive.

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

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

With no annotations, the description carries the burden well: it explains that prices are advertised base prices before taxes and extra fees, defines the 'verified' flag and its freshness window, discloses the default filtering behavior, and states the sort order. It stops short of noting auth needs, rate limits, or result-size behavior, but the essential semantics of the returned data are covered.

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?

Front-loads the core action and scope in the first sentence, then layers the return semantics, the verified concept, the default/filter behavior, and the sort order concisely. Every sentence carries information and none is redundant.

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?

With no output schema present, the description does the work of explaining what comes back (advertised base prices, cheapest-first monthly-equivalent sort, verified flag meaning) and how defaults shape results. An agent has enough to invoke and interpret this tool 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 100%, so the schema already documents all five parameters, making 3 the baseline. The description reinforces the meaning of include_unverified and the verified field and clarifies that prices are monthly-equivalent, adding modest value beyond the schema but no new syntax or format detail.

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 ('Download current BillWatch deal data and filter by category, provider or plan') and scopes the data precisely (US advertised base prices for streaming and VPN plans). The word 'current' implicitly contrasts with the sibling get_price_history, but that sibling is never named or compared 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?

Gives clear default behavior and the condition for the include_unverified flag ('By default only current, verified plans are returned; set include_unverified to also see stale or discontinued plans'). However, it offers no guidance on when to choose this tool over the sibling get_price_history, leaving the primary selection decision to inference.

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