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

Beyond the annotations, it discloses the critical behavioral traits: it can spend prepaid balance immediately, it can produce a payment_url requiring human checkout, it applies promo/welcome offers, and it explicitly instructs the agent to 'surface that link and the total and never imply the purchase is complete.' These are the high-stakes side effects an agent needs to know.

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?

The description is dense but every sentence earns its place by introducing a decision-critical piece of knowledge: use condition, balance impact, item shape, article_id source, checkout behavior, optional check_balance, and required auth scope. It is well accumulated with the riskiest information placed early.

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?

Despite having no output schema, the description tells the agent what to do with the purchase result—surface the payment_url and total and not claim completion—and clarifies partial vs full credit behavior, the need for a human checkout step, and the required 'order' scope. An agent has enough context to invoke this tool correctly and communicate the outcome safely.

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 even with no extra parameter detail in the description. The description echoes some parameter concepts—item format, tier-2 packs, project tag, article_id via list_site_articles—but these are already well documented in the input schema and add minimal new semantic meaning.

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?

The description opens with a clear gate—'Use this only when the user has selected placements and wants to place a backlink order'—and then states a specific action: 'Place an order for 1 to 20 backlinks across catalog sites.' It clearly identifies this as the create/purchase tool and distinguishes it from the sibling list/status/quote tools.

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 provides explicit when-to-use guidance, prerequisites, and sequencing: calls list_site_articles first to get article_id, calls check_balance to determine whether the payment will be full or partial, and warns against implying completion. The description tells the agent how to behave before, during, and after invocation.

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