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

Annotations already declare readOnlyHint=false and non-idempotent, so the mutating nature is covered; the description adds genuinely new behavioral facts: credit costs (100 light / 500 deep) and asynchronous execution requiring polling. It stops short of saying whether the call spends credits immediately or only when generation starts, and doesn't warn that repeat calls create separate articles and separate charges.

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?

Four short sentences, front-loaded with the action, then the author sourcing rule, then the cost model, then the async follow-up. Every sentence carries distinct information and none restates the schema verbatim.

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 3-parameter async creation tool with no output schema, it covers the important unknowns: cost, asynchrony, and the polling path. The one gap is that it never says what the call returns (presumably an article id) that article_status would be polled with, leaving the agent to infer the handle from the sibling's schema.

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 the baseline is 3; the description earns above that by mapping article_type values to credit costs, which the schema only expresses as word counts. The author_id default is repeated rather than extended, and topic gets no elaboration beyond 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?

"Start an article in an author's voice" gives a specific verb and resource, and the surrounding sentences tie it to list_authors and article_status, so it reads as the entry point of a generate-then-poll workflow. It doesn't explicitly rule out any sibling, but no sibling competes for the same action, so differentiation is effectively implicit.

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?

It states exactly how to supply the author (pass author_id from list_authors, or omit to use the active author) and prescribes the follow-up step ("Poll article_status"). What's missing is any guidance on choosing between article types beyond cost, or on when not to use this tool.

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