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

Annotations already declare the safety profile (readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false). Beyond that, the description discloses that the KB router itself performs scraping for url/sitemap sources, which is genuinely behavioral context an agent would not get from annotations. It omits failure modes, quota limits (get_kb_quota exists as a sibling) and whether repeated calls create duplicates.

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-loads purpose, then alternative, then one compact recipe per sourceType. Telegraphic phrasing, but every clause carries a distinct decision rule and there is no filler.

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 an 11-parameter mutation with no output schema, the description covers the hard part — selecting the right sourceType and correct field combination. Minor gaps remain: nothing about what is returned (created doc id), whether the call blocks on scraping, or quota/limit constraints.

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, per-parameter meanings are already documented, so the baseline is 3. The description goes further by specifying cross-parameter dependencies — which fields are required together for each sourceType and that scrapeContent must be true for url/sitemap — information the flat schema cannot express.

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: 'Add one knowledge base source (VG agents).' It immediately scopes to a single source and names the sibling (create_kb_from_urls) it is not, so an agent can distinguish it without opening either schema.

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?

Gives explicit routing rules: many page URLs → create_kb_from_urls; individual/website → sourceType=url with urls[] + scrapeContent=true; whole-site → sourceType=sitemap with sitemapUrl + maxPages; raw text → sourceType=doc. It also states a negative constraint ('do not paste web-fetched HTML here'), leaving nothing to inference.

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