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

Annotations already cover the read-only, idempotent, non-destructive, closed-world profile, yet the description adds real context: result size for an unfiltered query and the fact that these are internal lookup values that should not be cited as sources. It doesn't discuss pagination or ordering, which keeps it below 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?

Front-loaded with the core behavior and filtering advice, with examples embedded inline. The bolded data-sources paragraph is longer than strictly necessary for selection, though it does carry the citability rule, so it still earns its place.

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 annotations covering safety, an output schema covering return values, and full parameter coverage, the description supplies exactly the missing pieces: scope, filter strategy, result volume, and citation caveats. Nothing needed to invoke it correctly is absent.

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 baseline is 3. The description's examples for q and country_code largely restate the schema, and it never mentions the deprecated country_id alias, so it adds only the marginal behavioral note that omitting q returns the full catalogue.

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 ("Returns all political parties") plus the scoping dimension ("for the requested countries"). It also situates the data relative to siblings by noting party names appear in actor and vote records, so an agent can tell this apart from get_party or list_actors.

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 operating guidance: omit country_code for all accessible countries, use q for name/acronym matching, and "resolve the name here rather than reading the list and guessing." The 91-row Colombia example concretely motivates the filter. It stops short of naming when to prefer the singular get_party sibling.

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