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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds real semantic context the annotations cannot: entries carry expression IDs, source hashes, consolidation markers, and the warning that markers identify text but do not prove when it applied. Pagination/limits are not mentioned.

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?

Four tight sentences with no filler; the core scope is front-loaded, followed by entry contents, the semantic caveat, the handoff to lookup_provision, and the asAt condition.

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?

An output schema exists, so return-value explanation is not required, yet the description still characterizes entries usefully. The only gap is the unexplained asAt reference, which has no matching input parameter.

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% with only two params, so the schema already documents work (ELI URI) and sourceLang. The description adds no further parameter detail, and its mention of 'asAt' does not correspond to any input parameter, which slightly muddies rather than clarifies.

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 precise verb and resource ('Find same-language publisher expressions for one EU act') and scopes it to held official text versions, which distinguishes it from siblings like lookup_provision, provision_history, and recent_changes.

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?

It gives explicit downstream routing ('Pass a returned expression ID to lookup_provision to read that exact text') and a conditional rule for asAt ('only when the source carries an explicit validity window'). It stops short of naming when-not-to-use or contrasting against other listing tools such as provision_history.

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