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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so the safety profile is covered. The description adds genuinely useful context beyond that: California-only scope, 'Keyless' auth (no credentials needed), and HCAI CTRx program provenance. It doesn't discuss rate limits or response size behavior for the limit param, but the added context is real.

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-loaded with the returned data, then usage routing, then lookup mechanics and operational tags. Every clause earns its place, though the trailing fragments ('Part of HCAI's CTRx program. California-only. Keyless.') are terse to the point of choppiness.

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, the description carries the burden of describing returns, which it does ('every prior increase for that NDC... with its date and amount'). Scope, auth, region, and lookup path are all covered; only edge behavior for the year/limit filters is absent, which 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 coverage is 100%, so the schema already documents ndc, year, and limit with formats and ranges. The description reinforces the NDC-centric lookup and how to obtain an NDC, adding marginal meaning, but says nothing about the year or limit parameters. 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?

States a specific verb+resource (5-year WAC increase history for a given NDC) with explicit scope (California, preceding 5 calendar years, date and amount). It explicitly distinguishes itself from the sibling ca_rx_wac_increases by contrasting 'full price trajectory' with 'latest jump'.

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 explicit when-to-use ('see a drug's full price trajectory rather than just its latest jump'), names the alternative tool, and provides a prerequisite workflow ('get one from ca_rx_wac_increases first if you only have a drug name'). Nothing is left to inference.

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