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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so the safety profile is covered. The description adds real context beyond that: it fetches the PDF live from ota.ca.gov and lists the concrete fields returned, with a 'best-effort' caveat on statute citations. It omits failure behavior for a missing citation, keeping it short of a 5.

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?

A single front-loaded sentence opens with the purpose, then appends source and return detail. Dense but free of filler; the long comma-separated field list is the only thing that mildly hurts readability.

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 return-value burden and does so by enumerating the fields returned and noting the data source. Missing only edge-case handling (invalid citation, network failure) for a public read-only lookup, which keeps it just under complete.

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 baseline is 3. The description goes slightly beyond the schema by explaining what the trailing 'P' signifies -- a Precedential versus Nonprecedential opinion -- which is semantic meaning the raw schema note ('may be omitted') does not convey.

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 -- 'Look up a California Office of Tax Appeals opinion by its OTA citation' -- with concrete citation examples. The citation-lookup framing naturally distinguishes it from the sibling ca_ota_search, so an agent can tell the two apart without opening either schema.

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 phrase 'by its OTA citation' implies you must already hold a citation, which is useful context, but the description never states when to prefer this over ca_ota_search or what to do when no citation is known. Usage is implied rather than explicit, with no exclusions or named alternatives.

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