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

Annotations already declare read-only, idempotent, open-world, non-destructive behavior, so safety is covered. The description adds substantive context beyond that: the full field set returned (appointments, confirmation/commission dates, Senate vote, senior status, education) and the coverage span since 1789. It omits any note on match ambiguity or how the limit affects partial-name searches.

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 action and source, then enumerates returned fields and query types in one dense paragraph. Every clause is informative, though the long field enumeration makes it heavier than strictly necessary.

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 burden of describing returns and does so thoroughly, listing appointment, date, biographical and career fields plus the questions it answers. An agent has enough to invoke it correctly and interpret results.

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%, with both name (including partial-name examples) and limit (default/max) fully documented in the schema. The description adds no parameter-level syntax or format detail beyond what the schema provides, 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?

States a specific verb (look up), a precise resource (US federal Article III judge), and the source (FJC biographical directory), with scope (all justices, appellate and district judges since 1789). This cleanly distinguishes it from the by-court and by-president siblings, which select on different axes.

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 description conveys when to reach for it via the example questions it answers ("who appointed Judge X", "when was X confirmed", "is X still serving"), which map to name-based lookup rather than court/president browsing. It does not explicitly name fjc_judges_by_court or fjc_judges_by_president as the alternatives, so it falls short of a full when/when-not statement.

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