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

Annotations (readOnlyHint=false, openWorldHint=true) establish this is a mutating open-world tool; the description adds substantial context beyond that: cost (400 Sinapses, refunded on failure), synchronous execution under a timeout rule, and no idempotency (blind retry creates a second draft and double charges). However, several write behaviors (what update replaces, whether publish changes URL) are only implied. Strong added value, so a 3+ rather than higher.

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?

Dense but front-loaded: the port-choice decision (create vs generate) comes before action details, which is the highest-value information. It is long and partially restates schema descriptions (coverImageId, brandSlug), costing it the top mark, but every sentence carries routing or cost information.

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 21-parameter, six-action tool with no output schema, the description covers all actions, cost model, identity/sessionToken, timeout behavior, and cross-tool dependencies (sapiens_image, sapiens_brand, sapiens_gallery, sapiens_repertorio). Nothing an agent needs to call 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 86%, so the schema already carries most parameter meaning (baseline 3). The description adds the 'why' for key params: brandSlug controls whose design system styles the cover/images, and coverImageId/coverImageUrl override the courtesy cover when an image already exists. Marginal but real value above the schema.

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+resource and scope: user's own self-serve articles at /u/<username>, explicitly NOT the editorial blog. It names the sibling it is not (sapiens_article for the curated editorial blog) and enumerates all six sub-actions, so an agent can tell exactly what it does.

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?

Explicit routing guidance: text the person already wrote goes to create (free), AI only in generate (400 Sinapses), and burning 400 by generating then overwriting is called out as a mistake. It also names the alternative (sapiens_article) and gives a timeout/idempotency warning with the prescribed check (action=list before retrying).

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