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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds real behavioral scope beyond that: only recent final votes, amendments excluded, and a cap of three groups.

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?

The trigger condition is front-loaded in the first clause, followed by the example and the necessary group vocabulary. There is no filler, though the group enumeration makes it a fairly dense single block rather than a cleanly segmented one.

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 should hint at what comes back; the example ('how often did EPP and S&D vote the same way') implies an agreement-rate style result but never states the return shape explicitly. Everything needed to select and invoke it correctly is otherwise present.

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, but the description adds substantive meaning the schema lacks: it enumerates the valid group names (The Left, S&D, Greens/EFA, Renew, EPP, ECR, PfE, ESN) even though the 'groups' array has no enum, and it clarifies that 'limit' counts newest votes.

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 states a specific verb and resource ('compare how two or three European Parliament political groups voted') and scopes it to recent final votes on texts. It clearly distinguishes itself from the single-record siblings (get_vote, list_votes) by being a cross-group comparison tool.

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?

'Use this when the user wants to compare...' gives an explicit trigger, reinforced by a concrete example query (EPP vs S&D agreement). It also states a scoping exclusion (amendments left out) and the 2-3 group constraint, though it does not name sibling alternatives the way a top-tier definition would.

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