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

Annotations declare destructiveHint=true and idempotentHint=true, but the description supplies the operational consequences: writes are LIVE and visible to readers immediately on a published article, per-language fields merge rather than replace, categories replaces the additional-category set, published=false reverts to draft, and rehost_images is ON by default. It further lists 403/404/400 failure modes and the exact return shape, which annotations cannot convey.

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 two facts that change agent behavior (partial update, writes LIVE) before the parameter enumeration, and the IMPORTANT block is placed where it will be seen. The Args list largely mirrors the schema's own descriptions, so there is some redundancy, but no sentence is 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 a 13-parameter mutation tool with nested per-language objects and no output schema, the description still covers return values ('{ status: "success", article: {...}, images? }'), error codes, idempotency escape hatches, and the safer staged-edit alternative. Nothing needed to invoke it correctly is missing.

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, but the description earns above that by clarifying genuinely ambiguous semantics: 'categories ... replace the set' versus the schema's vaguer 'attach', the markdown-without-content_format pitfall, and external_id's upsert behavior. The only lapse is that the required agent_key parameter is omitted from the Args list, though the schema documents it thoroughly.

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+resource+scope: 'Update an existing article by id in the connected HelpCenter.io help center,' and immediately qualifies it as a partial update. This cleanly separates it from helpcenter_create_article, helpcenter_bulk_create_articles, and helpcenter_stage_article_changes without requiring the agent to open sibling 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 states the condition that selects an alternative: 'To prepare an edit privately and release it deliberately, use helpcenter_stage_article_changes and helpcenter_publish_staged_changes instead.' It also names the write-scoped API key prerequisite, which gates whether the call can succeed at all.

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