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

Goes well beyond the annotations: it discloses reversibility (done=false reopens), the exact failure mode for ineligible or unknown ids (an Unknown item_id error), and a precedence rule that a later recheck_page result overrides the mark. These are the mutation semantics an agent needs and none are in the structured fields.

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 sentences, front-loaded with purpose then usage then eligibility then precedence, with no filler. The density is high but nearly every clause carries a constraint; a slightly trimmed phrasing of the error clause would tighten it further.

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 three-param mutation with no output schema, the description covers eligibility, failure behavior, reversibility, and interaction with recheck_page. Only scan_id's role and what a successful response looks like are left unaddressed.

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 only 33%, and the description compensates for two of three params: it explains done's default/inverse behavior and constrains item_id to do_first-or-smaller ids with an explicit error otherwise. scan_id is never explained in either the schema or the description, which is the remaining gap.

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 (mark) plus the exact resource (one item of get_actions), including the inverse behavior for done=false. This is immediately distinguishable from sibling tools like get_actions, recheck_page, and write_wording.

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?

Gives explicit when-to-use (owner says an item is done, or recheck_page cannot confirm) and names the alternative tool by name. It also states when NOT to use it: ask_owner_first and also_fix items are rejected, tying eligibility back to get_actions' buckets.

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