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

Annotations already declare readOnlyHint, idempotentHint and non-open-world, so the safety profile is covered. The description adds only that results are published items with title/summary/url, which the output schema likely already covers; nothing about ordering, result limits, or missing translations.

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 short sentences, front-loaded with the resource and payload description. The closing lang sentence is largely redundant with the schema, a minor wasted line.

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 a single optional parameter, full annotation coverage and an output schema, the definition gives an agent everything needed to call it and to know the follow-up path via get_document. Only the missing sibling differentiation and result-size expectations keep it from a 5.

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% and the enum already documents nl/en including the default. The description's "lang is nl or en" merely restates the schema without adding fallback or selection semantics, so baseline 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?

The description names a specific resource (published case studies, client and own projects) and states what each item carries (title, summary, url), so an agent knows exactly what comes back. It implicitly separates itself from get_document as the full-read path, though it doesn't differentiate from list_documents or search_knowledge_base.

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?

"Read one in full with get_document" gives an explicit routing rule to the sibling tool for the detail follow-up. It does not state exclusions (e.g., when to use search_knowledge_base instead for topical lookup), so it stops short of full when/when-not guidance.

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