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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, but the description adds genuinely new behavioral context: the merge/preserve semantics, that `published` toggles the public page state, and that every update fires an `article.updated` webhook. Webhook side effects and public-page exposure are not derivable from the annotations.

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?

Three short sentences, front-loaded with the operation and semantics; each sentence adds distinct information (merge behavior, publish toggle, webhook) with no redundancy or 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 mutation tool with annotations and an output schema, the description covers the essential non-obvious behaviors: partial update, publish/unpublish side effect, webhook emission. It stops short of noting permission requirements or whether changing `format` alters how `content` is interpreted, which would be the remaining gaps.

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 only 11% — eight of nine parameters (slug, title, author, format, content, categories, description) are undocumented in both schema and description. The description explains only the general merge behavior and calls out `published`; it does not compensate for the large coverage gap on the remaining fields.

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?

Names a specific verb and resource ('Partially update an existing Polyblog article by id'), and the qualifier 'partially' plus 'only the fields you pass are changed' precisely distinguishes it from a full replacement or from create/delete sibling operations. An agent can identify the operation without opening the 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?

Usage context is implied by the PATCH-style semantics ('only the fields you pass are changed'), which tells the agent this is for targeted edits rather than rewrites. However, no alternative is named (e.g., create_article, delete_article, get_article) and no preconditions or when-not-to-use guidance is given.

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