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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered structurally. The description contributes scope details (national aggregates, explicit denominators, inclusion of below-threshold and invalid ballots) but says nothing about return shape, aggregation unit, or any ordering/rounding behavior.

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 sentences, both front-loaded with the substantive information; the second sentence functions as a useful exclusion filter. The phrase 'with explicit denominators' is slightly compressed but does not pad the text, and nothing 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?

For a one-optional-parameter read tool with no output schema, this is nearly sufficient: it discloses what categories of votes are counted and what is deliberately excluded. The remaining gap is that, absent an output schema, the description does not sketch the response structure beyond naming the components.

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% and the single election_id parameter is documented in-schema, including the caveat that a bare '2019' is ambiguous. The description adds no additional meaning about how election_id resolves or what 'latest' means in this dataset, so the baseline of 3 applies.

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 names the concrete figures produced (regular and double-envelope CEC votes, below-threshold valid votes, invalid ballots) and their denominators, so an agent knows exactly what data class this returns. It also fences the tool off from forecast/analytics siblings by stating 'National aggregates, not voter-flow or seat forecasts,' though it never names a specific sibling and leaves the 'CEC' acronym unexplained.

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 negative scoping in 'not voter-flow or seat forecasts' implicitly steers the agent away from get_analytics or similar siblings, which is useful exclusion guidance. However, there is no explicit statement of when to call this instead of get_summary or get_election, so the routing must be inferred.

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