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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful behavior beyond that: it reports every session served and joins the two employee numbers a member holds after moving between chambers. It does not say how ambiguous name matches are resolved or what happens when no legislator is found, which matters for a flexible-identifier lookup.

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 with no waste, leading with what is returned and following with the identity-join caveat. Nothing is restated from the title or annotations.

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 an output schema present, return values need no explanation, and all three parameters are fully documented. The definition covers scope and identity resolution well; only edge-case behavior (ambiguous or unmatched identifiers, and whether year bounds narrow the session list) is left unaddressed.

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 schema already documents legislator, fromYear and toYear. The description repeats the accepted identifier forms without adding syntax or precedence rules, and says nothing about the year-range parameters beyond what the schema states.

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 resource (one legislator's Liberty Rating per session) and how the target is identified (name, slug, personId or employeeNo). It is clearly distinguishable from legislator_votes (votes) and legislators_for_town (by-town lists), though it does not name those siblings explicitly.

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?

Usage is only implied: an agent can infer this is the lookup for a single member's rating history across sessions. There is no explicit when-to-use, when-not-to-use, or pointer to an alternative tool for related questions.

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