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

Annotations already declare readOnly/idempotent/openWorld, and the description adds non-obvious behavior: pagination via nextOffset must repeat the same topic, language, and dates; labels stay in the requested metadata language; unknown labels stay unknown rather than falling back. It does not discuss rate limits or return envelope shape, but the output schema covers the latter.

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 purpose sentence, then the topic-routing clause, then operational notes; no filler. Dense but appropriate for an 11-value enum tool, though the longer trailing sentences about labels could be tightened.

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 paginated reference-dictionary tool with a full output schema and complete annotation coverage, the description supplies everything an agent needs: topic routing, the sessions-only date rule, pagination invariants, and label-language behavior. Return shape is left to the output schema, as allowed.

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 baseline is 3; the description earns a bump by adding semantics the schema lacks — that dateFrom/dateTo are meaningful only for the sessions topic, and that offset continuation requires holding topic, language, and dates constant. It does not explain limit clamping, but the schema already does.

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?

Opens with a specific verb and resource ("List Swiss Parliament reference entries and source coverage") and then enumerates every topic value, so an agent knows exactly what class of data this returns. It does not name sibling tools, but the reference/dictionary nature is clearly distinct from the chparl_search_* and chparl_get_* tools.

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?

Explicitly routes each topic to its use case: identifiers/coverage/languages for server explanations, statuses for the legacy/current snapshot, and the remaining topics for live dictionaries. It also states the key conditional constraint that "Date filters apply only to sessions," which prevents a common misuse.

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