books_email_purchase_order

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

With no annotations, the description must carry the full burden of behavioral disclosure. It does not mention potential side effects, such as whether sending an email changes the purchase order's status, whether it requires special permissions, or if it just sends a static PDF. This is opaque for an action with external effects.

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 one short sentence, front-loaded and free of unnecessary words. It is extremely concise, but this comes at the cost of omitting critical information. Still, for the tiny amount of text, it is well-structured.

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?

Given the tool's complexity (6 parameters, no annotations, no output schema), the description is profoundly inadequate. It fails to explain how to use the parameters, what the email contains, or any preconditions. An agent cannot reliably invoke this tool correctly based on this description alone.

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?

The schema has 6 parameters with 0% coverage in the description, and the description itself mentions none of them. It does not compensate for the lack of schema descriptions. The agent is left to infer the meaning of fields like body, cc_mail_ids, and send_attachment without any assistance.

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 'Email a purchase order' uses a specific verb and resource, clearly identifying the action. While it essentially restates the tool name, it still distinguishes this tool from other purchase order operations. However, it lacks any detail about scope or variations.

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?

No guidance is provided on when to use this tool compared to alternatives like books_send_invoice_email or books_email_credit_note. There is no mention of prerequisites, such as the purchase order already existing, or when emailing is appropriate.

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