manage_x_posting_addon

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

Goes well past the annotations by disclosing that the preview charges nothing, that confirming returns a Stripe Checkout link, and that the card is only charged after the user pays on that page, plus the already-active-add-on fallback and the required scope (billing:write, owner/admin). What is missing is any statement about the non-idempotent retry surface — e.g. what happens if confirm is called twice with the same preview_id — which matters given idempotentHint=false and destructiveHint=true.

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 and the plan menu, then walks the preview→confirm→checkout sequence in order; every sentence carries either a price, a state transition, or a permission requirement. No filler or restatement of the tool name.

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 an 8-parameter, two-step payment flow with no output schema, the description covers the quote payload, the confirm payload, the returned Checkout link, the no-charge guarantee, the active-add-on branch, and the auth scope. The only real gap is retry/idempotency behavior for confirm and whether the preview expires.

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 adding the per-plan pricing table (which the enum lacks in the schema) and by attributing expected_plan_code, expected_price_usd, expected_addon_status and preview_id to the prior preview call, clarifying their provenance and ordering. It still doesn't explain when workspace_id is needed beyond what the schema says.

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 ("Buy an X posting add-on") and immediately enumerates the purchasable plan codes with prices, so the agent knows exactly which capability this is versus upgrade_subscription or manage_extra_account. The trailing cross-reference to get_x_posting_quota further separates allowance-reading from purchasing.

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 two-phase protocol: call without confirm to get a price, show it to the user, then call again with confirm=true and the preview fields. It also names the alternative path when an add-on is already active (billing page for the owner, no second plan), removing the main branch ambiguity.

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