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

Goes beyond annotations by disclosing the quota cost ('Spends one monitor'), the return shape (created check plus id, valuable since there is no output schema), and the idempotency behavior in concrete terms ('the same plan id returns the first result'). This is consistent with idempotentHint=true and destructiveHint=false, and adds substantive context the annotations alone do not convey.

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, each carrying distinct information (precondition, return, cost, idempotency, exclusion). The precondition is front-loaded and nothing repeats structured fields 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?

With no output schema, the description compensates by stating the return value and id; with annotations covering safety, it adds quota cost and idempotency; schema covers both parameters fully. An agent has everything needed to invoke correctly.

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 100%, so both plan_id and confirm (including the requirement to show the confirm sentence to the user) are already documented in the schema. The description only implies the plan-confirmation prerequisite and adds no format or syntax detail beyond that; baseline 3 applies.

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 action (create the content check from a confirmed plan_content_check plan) and its return (the created check with its id). It is clearly distinguishable from plan_content_check (which produces the plan) and update_monitor (which changes an existing check).

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 an explicit trigger ('when the user has confirmed a plan_content_check plan') and an explicit exclusion with the correct alternative ('Not for changing an existing check: use update_monitor'). No inference required.

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