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

Beyond the readOnly/idempotent/openWorld annotations it discloses the paging contract and snapshot coupling, that missing detail returns found false rather than erroring, that historical participation groups stay historical, and that linked files are linked rather than parsed. These are non-obvious behaviors an agent could not infer from annotations or schema alone.

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, then paging, then error/alternative handling – a logical order for a six-parameter read tool. The semicolon-chained, telegraphic phrasing (e.g. "Historical participation groups remain historical") is compact but occasionally terse enough to slow parsing.

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?

Covers everything an agent needs: sectioning, paging invariants, missing-detail behavior, and sibling routing. Return shape need not be described because an output schema exists, and the readOnly annotations already carry the safety profile.

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?

With 100% schema coverage the baseline is 3, but the description adds real meaning: the snapshot/offset relationship across a single selected collection and the overview-versus-section tradeoff between scalars and complete paged items. It does not explain the local-versus-returned page limits or the language fallback beyond what the schema already says.

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 and resource plus the exact sub-resources readable (title, stage, events, participants, documents), mapping directly onto the section enum. It also names the sibling it is not (euparl_list_procedures for discovery), so an agent can choose between them without opening schemas.

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 explains the default overview versus selecting a collection section, how to continue paging (page.next_offset plus the returned snapshot), and the reset rule (offset 0 without snapshot when the collection changes). It also routes to euparl_list_procedures for reference discovery and euparl_search_documents mode get for linked documents.

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