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

Annotations already cover the safe-read profile, and the description goes beyond them with real behavior: the rules come from the same source the in-app writer uses, X counts each link as 23, linkedin_article is person-published (Mark doesn't publish Articles), and for blog/faq/competitor_page it reports CMS connectivity and whether approval drafts or publishes live. Missing only how the CMS-mapping report is keyed when no CMS is connected.

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 core purpose and the contents list, then the alternative, then the per-channel special cases. Dense but every clause carries information; the linkedin_article aside is slightly chatty but genuinely differentiating.

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 shape needn't be described. With one optional enum parameter, 100% schema coverage, and clear annotations, the description covers everything an agent needs to choose and call this: what it returns, per-channel quirks, and the sibling alternative.

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 constrains values, so the schema does most of the work. The description still adds meaning the schema doesn't: the omission behavior for channel and the distinction between linkedin and linkedin_article (long-form Article with title required, cover optional).

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?

States a specific verb and resource ('gives the format rules for a channel') and enumerates the concrete contents: length limits, media ratios, meta field names/types, and CMS mapping. It also disambiguates against the nearest sibling by naming get_drafting_guide.

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 routes the agent: writing craft and workspace rules go to get_drafting_guide, omitting channel lists supported channels, and the Related line points at list_channels/save_post/get_brand_context/get_website_cms. Both the when and the when-not are present.

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