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

Annotations only supply the generic safety profile (not read-only, open-world, non-idempotent). The description goes well beyond: it enumerates the return shape { status, url, message }, explains both status branches, and clarifies that nothing is charged until the user finishes checkout.

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-loads the action, then the return contract, then the invocation condition. Sentences are dense but each carries distinct, necessary information with no filler.

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 non-idempotent mutation with no output schema, the description fully covers what an agent needs: preconditions, both return branches, and the fact that no charge occurs until the user completes Stripe checkout.

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 still adds meaning by constraining the workspaceId to a 'free workspace' and noting monthly-only-from-chat for interval, which frames the allowed values beyond the enum listings.

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 up front: 'Start buying a Replo plan for a free workspace.' It also names the sibling (get_plan_options) that feeds it, so an agent can place it in the workflow without opening other schemas.

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?

'Call only after the user chose the plan, usually from get_plan_options' gives an explicit precondition and source tool. It also draws the when-not boundary: workspaces that already have a plan route to manage_in_dashboard and chat never changes an existing subscription.

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